|
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Use the commands in this chapter to configure and monitor transparent bridging networks. For transparent bridging configuration information and examples, refer to the "Configuring Transparent Bridging" chapter in the Bridging and IBM Networking Configuration Guide.
Use the access-list global configuration command to provide extended access lists that allow more detailed access lists. These lists allow you to specify both source and destination addresses and arbitrary bytes in the packet.
access-list access-list-number {permit | deny} source source-mask destination destination-mask offset size operator operand
Syntax Description
access-list-number Integer from 1100 to 1199 that you assign to identify one or more permit/deny conditions as an extended access list. Note that a list number in the range 1100 to 1199 distinguishes an extended access list from other access lists. permit Allows a connection when a packet matches an access condition. The Cisco IOS software stops checking the extended access list after a match occurs. All conditions must be met to make a match. deny Disallows a connection when a packet matches an access condition. The software stops checking the extended access list after a match occurs. All conditions must be met to make a match. source Media Access Control (MAC) Ethernet address in the form xxxx.xxxx.xxxx. source-mask Mask of MAC Ethernet source address bits to be ignored. The software uses the source and source-mask arguments to match the source address of a packet. destination MAC Ethernet value used for matching the destination address of a packet. destination-mask Mask of MAC Ethernet destination address bits to be ignored. The software uses the destination and destination mask arguments to match the destination address of a packet. offset Range of values that must be satisfied in the access list. Specified in decimal or in hexadecimal format in the form 0xnn. The offset is the number of bytes from the destination address field; it is not an offset from the start of the packet. The number of bytes you need to offset from the destination address varies depending on the media encapsulation type you are using. size Range of values that must be satisfied in the access list. Must be an integer 1 to 4. operator Compares arbitrary bytes within the packet. Can be one of the following keywords: lt—less than gt—greater than eq—equal neq—not equal and—bitwise and xor—bitwise exclusive or nop—address match only operand Compares arbitrary bytes within the packet. The value to be compared to or masked against.
Defaults
No extended access lists are established.
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
After an access list is initially created, any subsequent additions (possibly entered from the terminal) are placed at the end of the list. In other words, you cannot selectively add or remove access list command lines from a specific access list.
An extended access list should not be used on FDDI interfaces that provide transit bridging.
 |
Note Due to their complexity, extended access lists should only be used by those who are very familiar with the Cisco IOS software. For example, to use extended access lists, it is important to understand how different encapsulations on different media would generally require different offset values to access particular fields. |
 |
Caution Do not specify offsets into a packet that are greater than the size of the packet. |
Examples
The following example permits packets from MAC addresses 000c.1bxx.xxxx to any MAC address if the packet contains a value less than 0x55AA in the 2 bytes that begin 0x1e bytes into the packet:
interface ethernet 0
bridge-group 3 output-pattern 1102
access-list 1102 permit 000c.1b00.0000 0000.00ff.ffff
0000.0000.0000 ffff.ffff.ffff 0x1e 2 lt 0x55aa
The following example permits an NOP operation:
interface ethernet 0
bridge-group 3 output-pattern 1102
access-list 1101 permit 0000.0000.0000 ffff.ffff.ffff 0000.0000.0000 ffff.ffff.ffff Bridged protocols on Ethernet0/3: clns decnet vines apollo novell xns Software MAC address filter on Ethernet0/3 Hash Len Address Matches Act Type 0x00: 0 ffff.ffff.ffff 0 RCV Physical broadcast 0x00: 1 ffff.ffff.ffff 0 RCV Appletalk zone 0x2A: 0 0900.2b01.0001 0 RCV DEC spanning tree 0x49: 0 0000.0c36.7a45 0 RCV Interface MAC address 0xc0: 0 0100.0ccc.cccc 48 RCV CDP 0xc2: 0 0180.c200.0000 0 RCV IEEE spanning tree 0xF8: 0 0900.07ff.ffff 0 RCV Appletalk broadcast
Table 3 describes significant fields shown in the display.
| Field | Description |
|---|---|
Routed protocols on | List of the routed protocols configured for the specified interface. |
Bridged protocols on | List of the bridged protocols configured for the specified interface. |
Software MAC address filter on | Table of software MAC address filter information for the specified interface. |
Hash | Hash key/relative position in the keyed list for this MAC-address entry. |
Len | Length of this entry to the beginning element of this hash chain. |
Address | Canonical (Ethernet ordered) MAC address. |
Matches | Number of received packets matched to this MAC address. |
Act | Action to be taken when that address is looked up; choices are to receive or discard the packet. |
Type | MAC address type. |
Related Commands
Establishes MAC address access lists Builds type-code access lists. Associates an extended access list with a particular interface.
Command
Description
Use the access-list global configuration command to establish MAC address access lists. Use the no form of this command to remove a single access-list entry.
access-list access-list-number {permit | deny} address mask
Syntax Description
access-list-number Integer from 700 to 799 that you select for the list. permit Permits the frame. deny Denies the frame. address mask 48-bit MAC addresses written in dotted triplet form. The ones bits in the mask argument are the bits to be ignored in address.
Defaults
No MAC address access lists are established.
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Configuring bridging access lists of type 700 may cause a momentary interruption of traffic flow.
Examples
The following example assumes that you want to disallow the bridging of Ethernet packets of all Sun workstations on Ethernet interface 1. Software assumes that all such hosts have Ethernet addresses with the vendor code 0800.2000.0000. The first line of the access list denies access to all Sun workstations, while the second line permits everything else. You then assign the access list to the input side of Ethernet interface 1.
access-list 700 deny 0800.2000.0000 0000.00FF.FFFF access-list 700 permit 0000.0000.0000 FFFF.FFFF.FFFF interface ethernet 1 bridge-group 1 input-address-list 700
Related Commands
Builds type-code access lists.
Command
Description
Use the access-list global configuration command to build type-code access lists. Use the no form of this command to remove a single access list entry.
access-list access-list-number {permit | deny} type-code wild-mask
Syntax Description
access-list-number User-selectable number between 200 and 299 that identifies the list. permit Permits the frame. deny Denies the frame. type-code 16-bit hexadecimal number written with a leading "0x"; for example, 0x6000. You can specify either an Ethernet type code for Ethernet-encapsulated packets, or a DSAP/SSAP pair for 802.3 or 802.5-encapsulated packets. Ethernet type codes are listed in the appendix "Ethernet Type Codes." wild-mask 16-bit hexadecimal number whose ones bits correspond to bits in the type-code argument that should be ignored when making a comparison. (A mask for a DSAP/SSAP pair should always be at least 0x0101. This is because these two bits are used for purposes other than identifying the SAP codes.)
Defaults
No type-code access lists are built.
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Type-code access lists can have an impact on system performance; therefore, keep the lists as short as possible and use wildcard bit masks whenever possible.
Access lists are evaluated according to the following algorithm:
If the length/type field is greater than 1500, the packet is treated as an LSAP packet unless the DSAP and SSAP fields are AAAA. If the latter is true, the packet is treated using type-code filtering.
If the LSAP-code filtering is used, all SNAP and Ethernet Type II packets are bridged without obstruction. If type-code filtering is used, all LSAP packets are bridged without obstruction.
If you have both Ethernet Type II and LSAP packets on your network, you should set up access lists for both.
Examples
The following example permits only LAT frames (type 0x6004) and filters out all other frame types:
access-list 201 permit 0x6004 0x0000
The following example filters out only type codes assigned to Digital (0x6000 to 0x600F) and lets all other types pass:
access-list 202 deny 0x6000 0x600F access-list 202 permit 0x0000 0xFFFF
Use the last item of an access list to specify a default action; for example, permit everything else or deny everything else. If nothing else in the access list matches, the default action is normally to deny access; that is, filter out all other type codes.
Related Commands
- Establishes MAC address access lists
Command
Description
Use the bridge acquire global configuration command to forward any frames for stations that the system has learned about dynamically. Use the no form of this command to disable the behavior.
bridge bridge-group acquire
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command.
Defaults
Enabled
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
When using the command default, the Cisco IOS software forwards any frames from stations that it has learned about dynamically. If you use the no form of this command, the bridge stops forwarding frames to stations it has dynamically learned about through the discovery process and limits frame forwarding to statically configured stations. That is, the bridge filters out all frames except those whose sourced-by or destined-to addresses have been statically configured into the forwarding cache. The no form of this command prevents the forwarding of a dynamically learned address.
Examples
The following example prevents the forwarding of dynamically determined source and destination addresses:
no bridge 1 acquire
Related Commands
Filters frames with a particular MAC-layer station source or destination address. Defines the type of STP.
Command
Description
Use the bridge address global configuration command to filter frames with a particular MAC-layer station source or destination address. Use the no form of this command to disable the forwarding ability.
bridge bridge-group address mac-address {forward | discard} [interface]
Syntax Description
bridge-group Bridge group number. It must be the same number specified in the bridge protocol command. mac-address 48-bit dotted-triplet hardware address such as that displayed by the EXEC show arp command, for example, 0800.cb00.45e9. It is either a station address, the broadcast address, or a multicast destination address. forward Frame sent from or destined to the specified address is forwarded as appropriate. discard Frame sent from or destined to the specified address is discarded without further processing. interface (Optional) Interface specification, such as Ethernet 0. It is added after the forward or discard keyword to indicate the interface on which that address can be reached.
Defaults
Disabled
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Any number of addresses can be configured into the system without a performance penalty.
|
Note MAC addresses on Ethernets are "bit swapped" when compared with MAC addresses on Token Ring and FDDI. For example, address 0110.2222.3333 on Ethernet is 8008.4444.CCCC on Token Ring and FDDI. Access lists always use the canonical Ethernet representation. When using different media and building access lists to filter on MAC addresses, keep this point in mind. Note that when a bridged packet traverses a serial link, it has an Ethernet-style address. |
Examples
The following example enables frame filtering with MAC address 0800.cb00.45e9. The frame is forwarded through Ethernet interface 1:
bridge 1 address 0800.cb00.45e9 forward ethernet 1
The following example disables the ability to forward frames with MAC address 0800.cb00.45e9:
no bridge 1 address 0800.cb00.45e9
Related Commands
Forwards any frames for stations that the system has learned about dynamically. Assigns an access list to a particular interface. Assigns an access list to a particular interface for filtering the MAC destination addresses of packets that would ordinarily be forwarded out that interface. Defines the type of STP.
Command
Description
Use the bridge bridge global configuration command to enable the bridging of a specified protocol in a specified bridge group. Use the no form of this command to disable the bridging of a specified protocol in a specified bridge group.
bridge bridge-group bridge protocol
Syntax Description
bridge-group Bridge-group number. It must be the same number specified in the bridge protocol command. protocol Any of the supported routing protocols. The default is to bridge all of these protocols.
Defaults
Bridge every protocol.
Command Modes
Global configuration
Command History
11.2 This command was introduced.
Release
Modification
Usage Guidelines
When IRB is enabled, the default route/bridge behavior in a bridge group is to bridge all protocols. You do not have to use the bridge bridge command to enable bridging.
You can use the no bridge bridge command to disable bridging in a bridge group so that it does not bridge a particular protocol. When you disable bridging for a protocol in a bridge group, routable packets of this protocol are routed when the bridge is explicitly configured to route this protocol, and nonroutable packets are dropped because bridging is disabled for this protocol.
|
Note Packets of nonroutable protocols such as LAT are only bridged. You cannot disable bridging for the nonroutable traffic. |
Examples
The following example disables bridging of IP in bridge group 1:
no bridge 1 bridge ip
Related Commands
Enables the Cisco IOS software to route a given protocol between routed interfaces and bridge groups or to route a given protocol between bridge groups. Defines the type of STP. Enables the routing of a specified protocol in a specified bridge group.
Command
Description
Use the bridge circuit-group pause global configuration command to configure the interval during which transmission is suspended in a circuit group after circuit group changes take place.
bridge bridge-group circuit-group circuit-group pause milliseconds
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command. circuit-group Number of the circuit group to which the interface belongs. milliseconds Forward delay interval. It must be a value in the range 0 to 10000 ms.
Defaults
0 ms pause
Command Modes
Global configuration
Command History
10.3 This command was introduced.
Release
Modification
Usage Guidelines
Circuit-group changes include the addition or deletion of an interface and interface state changes.
Examples
The following example sets the circuit group pause to 5000 ms:
bridge 1 circuit-group 1 pause 5000
Related Commands
Uses just the source MAC address for selecting the output interface. Assigns each network interface to a bridge group. Defines the type of STP.
Command
Description
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command. circuit-group Number of the circuit group to which the interface belongs.
Defaults
No bridge-group interface is assigned.
Command Modes
Global configuration
Command History
10.3 This command was introduced.
Release
Modification
Usage Guidelines
For applications that depend on the ordering of mixed unicast and multicast traffic from a given source, load distribution must be based on the source MAC address only. The bridge circuit-group source-based command modifies the load distribution strategy to accommodate such applications.
Examples
The following example uses the source MAC address for selecting the output interface to a bridge group:
bridge 1 circuit-group 1 source-based
Related Commands
Configures the interval during which transmission is suspended in a circuit group after circuit group changes take place. Assigns each network interface to a bridge group. Defines the type of STP.
Command
Description
Use the bridge cmf global configuration command to enable constrained multicast flooding (CMF) for all configured bridge groups. Use the no form of this command to disable constrained multicast flooding.
bridge cmfSyntax Description
This command has no arguments or keywords.
Defaults
Constrained multicast flooding is disabled.
Command Modes
Global configuration
Command History
11.2 This command was introduced.
Release
Modification
Examples
The following example enables constrained multicast flooding for all configured bridge groups:
bridge cmf
Related Commands
Clears transparent bridging multicast state information. Displays transparent bridging multicast state information.
Command
Description
Use the bridge crb global configuration command to enable the Cisco IOS software to both route and bridge a given protocol on separate interfaces within a single router. Use the no form of this command to disable the feature.
bridge crbSyntax Description
This command has no arguments or keywords.
Defaults
Concurrent routing and bridging is disabled.
When concurrent routing and bridging has been enabled, the default behavior is to bridge all protocols that are not explicitly routed in a bridge group.
Command Modes
Global configuration
Command History
11.0 This command was introduced.
Release
Modification
Usage Guidelines
When concurrent routing and bridging is first enabled in the presence of existing bridge groups, it generates a bridge route configuration command for any protocol for which any interface in the bridge group is configured for routing. This is a precaution that applies only when concurrent routing and bridging is not already enabled, bridge groups exist, and the bridge crb command is encountered.
Once concurrent routing and bridging has been enabled, you must configure an explicit bridge route command for any protocol that is to be routed on interfaces in a bridge group (in addition to any required protocol-specific interface configuration).
Examples
The following command enables concurrent routing and bridging:
bridge crb
Related Commands
Enables the routing of a specified protocol in a specified bridge group.
Command
Description
Use the bridge domain global configuration command to establish a domain by assigning it a decimal value between 1 and 10. Use the no form of this command to return it to a single bridge domain by choosing domain zero (0).
bridge bridge-group domain domain-number
Syntax Description
bridge-group Bridge group number specified in the bridge protocol ieee command. The dec keyword is not valid for this command. domain-number Domain ID number you choose. The default domain number is zero; this is the domain number required when communicating to IEEE bridges that do not support this domain extension.
Defaults
Single bridge domain
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Cisco has implemented a proprietary extension to the IEEE spanning-tree software in order to support multiple spanning-tree domains. You can place any number of routers within the domain. The routers in the domain, and only those routers, will then share spanning-tree information.
Use this feature when multiple routers share the same cable, and you wish to use only certain discrete subsets of these routers to share spanning-tree information with each other. This function is most useful when running other applications, such as IP UDP flooding, that use the IEEE Spanning-Tree Protocol. It can also be used to reduce the number of global reconfigurations in large bridged networks.
|
Caution Use multiple spanning-tree domains with care. Because bridges in different domains do not share spanning-tree information, bridge loops can be created if the domains are not carefully planned. |
|
Note This command works only when the bridge group is running the IEEE Spanning-Tree Protocol. |
Examples
The following example places bridge group 1 in bridging domain 3. Only other routers that are in domain 3 will accept spanning-tree information from this router.
bridge 1 domain 3
Related Commands
Defines the type of STP.
Command
Description
Use the bridge forward-time global configuration command to specify the forward delay interval for the Cisco IOS software. Use the no form of this command to return the default interval.
bridge bridge-group forward-time seconds
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command. seconds Forward delay interval. It must be a value in the range10 to 200 seconds.
Defaults
30-second delay
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
The forward delay interval is the amount of time the software spends listening for topology change information after an interface has been activated for bridging and before forwarding actually begins.
Each bridge in a spanning tree adopts the hello-time, forward-time, and max-age parameters of the root bridge, regardless of what its individual configuration might be.
Examples
The following example sets the forward delay interval to 60 seconds:
bridge 1 forward-time 60
Related Commands
Specifies that an interface is at the upstream point of traffic flow. Changes the interval the bridge will wait to hear BPDUs from the root bridge. If a bridge does not hear BPDUs from the root bridge within this specified interval, it assumes that the network has changed and will recompute the spanning-tree topology. Defines the type of STP.
Command
Description
Use the bridge-group interface configuration command to assign each network interface to a bridge group. Use the no form of this command to remove the interface from the bridge group.
bridge-group bridge-group
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63.
Defaults
No bridge group interface is assigned.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
You can bridge on any interface, including any serial interface, regardless of encapsulation. Bridging can be configured between interfaces on different cards, although the performance is lower compared with interfaces on the same card. Also note that serial interfaces must be running with HDLC, X.25, or Frame Relay encapsulation.
|
Note Several modifications to interfaces in bridge groups, including adding interfaces to bridge groups, will result in any Token Ring or FDDI interfaces in that bridge group being reinitialized. |
Examples
In the following example, Ethernet interface 0 is assigned to bridge-group 1, and bridging is enabled on this interface:
interface ethernet 0 bridge-group 1
Related Commands
Enables autonomous bridging on a ciscoBus2 controller. Assigns each network interface to a bridge group. Associates an extended access list with a particular interface in a particular bridge group. Associates an extended access list with a particular interface. Disables the spanning tree on a given interface.
Command
Description
Use the bridge-group aging-time global configuration command to set the length of time that a dynamic entry can remain in the bridge table from the time the entry was created or last updated. Use the no form of this command to return to the default aging-time interval.
bridge-group bridge-group aging-time seconds
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. seconds Aging time, in the range 0 to 1000000 seconds. The default is 300 seconds.
Defaults
300 seconds
Command Modes
Global configuration
Command History
10.3 This command was introduced.
Release
Modification
Usage Guidelines
If hosts on a bridged network are likely to move, decrease the aging-time to enable the bridge to adapt quickly to the change. If hosts do not transmit continuously, increase the aging time to record the dynamic entries for a longer time and thus reduce the possibility of flooding when the hosts transmit again.
Examples
The following example sets the aging time to 200 seconds:
bridge-group 1 aging-time 200
Related Commands
Assigns each network interface to a bridge group.
Command
Description
Use the bridge-group cbus-bridging interface configuration command to enable autonomous bridging on a ciscoBus2 controller. Use the no form of this command to disable autonomous bridging.
bridge-group bridge-group cbus-bridging
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63.
Defaults
Autonomous bridging is disabled.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Normally, bridging takes place on the processor card at interrupt level. When autonomous bridging is enabled, bridging takes place entirely on the ciscoBus2 controller, significantly improving performance.
You can enable autonomous bridging on Ethernet, FDDI (FCIT) and HSSI interfaces that reside on a ciscoBus2 controller. Autonomous bridging is not supported on Token Ring interfaces, regardless of the type of bus in use.
To enable autonomous bridging on an interface, that interface must first be defined as part of a bridge group. When a bridge group includes both autonomously and normally bridged interfaces, packets are autonomously bridged in some cases, but bridged normally in others. For example, when packets are forwarded between two autonomously bridged interfaces, those packets are autonomously bridged. But when packets are forwarded between an autonomously bridged interface and one that is not, the packet must be normally bridged. When a packet is flooded, the packet is autonomously bridged on autonomously bridged interfaces, but must be normally bridged on any others.
|
Note In order to maximize performance when using a ciscoBus2 controller, use the bridge-group cbus-bridging command to enable autonomous bridging on any Ethernet, FDDI, or HSSI interface. |
|
Note You can only filter by MAC-level address on an interface when autonomous bridging is enabled on that interface; autonomous bridging disables all other filtering, as well as priority queuing. |
Examples
In the following example, autonomous bridging is enabled on Ethernet interface 0:
interface ethernet 0 bridge-group 1 bridge-group 1 cbus-bridging
Related Commands
Assigns each network interface to a bridge group.
Command
Description
Use the bridge-group circuit-group interface configuration command to assign each network interface to a bridge group. Use the no form of this command to remove the interface from the bridge group.
bridge-group bridge-group circuit-group circuit-group
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. circuit-group Circuit group number. The range is 1 to 9.
Defaults
No bridge group interface is assigned.
Command Modes
Interface configuration
Command History
10.3 This command was introduced.
Release
Modification
Usage Guidelines
Circuit groups are primarily intended for use with HDLC-encapsulated serial interfaces. They are not supported for packet-switched networks such as X.25 or Frame Relay. Circuit groups are best applied to groups of serial lines of equal bandwidth, but can accommodate mixed bandwidths as well.
|
Note You must configure bridging before you configure a circuit group on an interface. |
Examples
In the following example, Ethernet interface 0 is assigned to circuit group 1 of bridge group 1:
interface ethernet 0 bridge-group 1 circuit-group 1
Related Commands
Configures the interval during which transmission is suspended in a circuit group after circuit group changes take place. Uses just the source MAC address for selecting the output interface.
Command
Description
Use the bridge-group input-address-list interface configuration command to assign an access list to a particular interface. This access list is used to filter packets received on that interface based on their MAC source addresses. Use the no form of this command to remove an access list from an interface.
bridge-group bridge-group input-address-list access-list-number
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. access-list-number Access list number you assigned with the access-list command. It must be in the range 700 to 799.
Defaults
No access list is assigned.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Examples
The following example assumes you want to disallow the bridging of Ethernet packets of all Sun workstations on Ethernet interface 1. Software assumes that all such hosts have Ethernet addresses with the vendor code 0800.2000.0000. The first line of the access list denies access to all Sun workstations, while the second line permits everything else. You then assign the access list to the input side of Ethernet interface 1.
access-list 700 deny 0800.2000.0000 0000.00FF.FFFF access-list 700 permit 0000.0000.0000 FFFF.FFFF.FFFF interface ethernet 1 bridge-group 1 input-address-list 700
Related Commands
Establishes MAC address access lists. Establishes MAC address access lists. Filters frames with a particular MAC-layer station source or destination address. Assigns an access list to a particular interface for filtering the MAC destination addresses of packets that would ordinarily be forwarded out that interface.
Command
Description
Use the bridge-group input-lat-service-deny interface configuration command to specify the group codes by which to deny access upon input. Use the no form of this command to remove this access condition.
bridge-group bridge-group input-lat-service-deny group-list
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. group-list
Defaults
No group codes are specified.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
This command prevents the system from bridging any LAT service advertisement that has any of the specified groups set.
Examples
The following example causes any advertisements with groups 6, 8, and 14 through 20 to be dropped:
interface ethernet 0 bridge-group 1 input-lat-service-deny 6 8 14-20
Related Commands
Assigns each network interface to a bridge group. Specifies the group codes by which to permit access upon input. Specifies the group codes by which to deny access upon output.
Command
Description
Use the bridge-group input-lat-service-permit interface configuration command to specify the group codes by which to permit access upon input. Use the no form of this command to remove this access condition.
bridge-group bridge-group input-lat-service-permit group-list
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. group-list
Defaults
No group codes are specified.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
This command causes the system to bridge only those service advertisements that match at least one group in the group list specified by the group-list argument.
If a message specifies group codes in both the deny and permit list, the message is not bridged.
Examples
The following example bridges any advertisements from groups 1, 5, and 12 through 14:
interface ethernet 1 bridge-group 1 input-lat-service-permit 1 5 12-14
Related Commands
Specifies the group codes by which to deny access upon input. Specifies the group codes by which to permit access upon output.
Command
Description
Use the bridge-group input-lsap-list interface configuration command to filter IEEE 802.2-encapsulated packets on input. Use the no form of this command to disable this capability.
bridge-group bridge-group input-lsap-list access-list-number
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. access-list-number Access list number you assigned with the standard access-list command. Specify a zero (0) to disable the application of the access list on the bridge group.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
This access list is applied to all IEEE 802.2 frames received on that interface prior to the bridge-learning process. SNAP frames must also pass any applicable Ethernet type-code access list.
Examples
The following example specifies access list 203 on Ethernet interface 1:
interface ethernet 1 bridge-group 3 input-lsap-list 203
Related Commands
Establishes MAC address access lists. Establishes MAC address access lists. Assigns each network interface to a bridge group. Filters IEEE 802-encapsulated packets on output.
Command
Description
Use the bridge-group input-pattern-list interface configuration command to associate an extended access list with a particular interface in a particular bridge group. Use the no form of this command to disable this capability.
bridge-group bridge-group input-pattern-list access-list-number
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. access-list-number Access list number you assigned using the standard access-list command. Specify a zero (0) to disable the application of the access list on the interface.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
Examples
The following command applies access list 1 to bridge group 3 using the filter defined in group 1:
interface ethernet 0 bridge-group 3 input-pattern-list 1
Related Commands
Establishes MAC address access lists. Assigns each network interface to a bridge group. Associates an extended access list with a particular interface.
Command
Description
Use the bridge-group input-type-list interface configuration command to filter Ethernet- and SNAP-encapsulated packets on input. Use the no form of this command to disable this capability.
bridge-group bridge-group input-type-list access-list-number
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. access-list-number Access list number you assigned with the standard access-list command. Specify a zero (0) to disable the application of the access list on the bridge group.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
For SNAP-encapsulated frames, the access list is applied against the 2-byte TYPE field given after the DSAP/SSAP/OUI fields in the frame.
This access list is applied to all Ethernet and SNAP frames received on that interface prior to the bridge learning process. SNAP frames must also pass any applicable IEEE 802 DSAP/SSAP access lists.
Examples
The following example shows how to configure a Token Ring interface with an access list that allows only the LAT protocol to be bridged:
interface tokenring 0 ip address 131.108.1.1 255.255.255.0 bridge-group 1 bridge-group 1 input-type-list 201
Related Commands
Establishes MAC address access lists. Assigns each network interface to a bridge group. Filters Ethernet- and SNAP-encapsulated packets on output.
Command
Description
Use the bridge-group lat-compression interface configuration command to reduce the amount of bandwidth that LAT traffic consumes on the serial interface by specifying a LAT-specific form of compression. Use the no form of this command to disable LAT compression on the bridge group.
bridge-group bridge-group lat-compression
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
Compression is applied to LAT frames being sent out the router through the interface in question.
LAT compression can be specified only for serial interfaces. For the most common LAT operations (user keystrokes and acknowledgment packets), LAT compression reduces LAT's bandwidth requirements by nearly a factor of two.
Examples
The following example compresses LAT frames on the bridge assigned to group 1:
bridge-group 1 lat-compression
Related Commands
Assigns each network interface to a bridge group.
Command
Description
Use the bridge-group output-address-list interface configuration command to assign an access list to a particular interface for filtering the MAC destination addresses of packets that would ordinarily be forwarded out that interface. Use the no form of this command to remove an access list from an interface.
bridge-group bridge-group output-address-list access-list-number
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. access-list-number Access list number you assigned with the standard access-list command.
Defaults
No access list is assigned.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Examples
The following example assigns access list 703 to Ethernet interface 3:
interface ethernet 3 bridge-group 5 output-address-list 703
Related Commands
Establishes MAC address access list.s Filters frames with a particular MAC-layer station source or destination address. Assigns each network interface to a bridge group. Assigns an access list to a particular interface.
Command
Description
Use the bridge-group output-lat-service-deny interface configuration command to specify the group codes by which to deny access upon output. Use the no form of this command to cancel the specified group codes.
bridge-group bridge-group output-lat-service-deny group-list
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. group-list List of LAT groups. Single numbers and ranges are permitted.
Defaults
No group codes are assigned.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
This command causes the system to not bridge onto this output interface any service advertisements that contain groups matching any of those in the group list.
Examples
The following example prevents bridging of LAT service announcements from groups 12 through 20:
interface ethernet 0 bridge-group 1 bridge-group 1 output-lat-service-deny 12-20
Related Commands
Establishes MAC address access lists. Assigns each network interface to a bridge group. Specifies the group codes by which to deny access upon input. Specifies the group codes by which to permit access upon output.
Command
Description
Use the bridge-group output-lat-service-permit interface configuration command to specify the group codes by which to permit access upon output. Use the no form of this command to cancel specified group codes.
bridge-group bridge-group output-lat-service-permit group-list
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. group-list LAT service advertisements.
Defaults
No group codes are specified.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
This command causes the system to bridge onto this output interface only those service advertisements that match at least one group in the specified group code list.
|
Note If a message matches both a deny and a permit condition, it will not be bridged. |
Examples
The following example allows only LAT service announcements from groups 5, 12, and 20 on this bridge:
interface ethernet 0 bridge-group 1 output-lat-service-permit 5 12 20
Related Commands
Specifies the group codes by which to permit access upon input. Specifies the group codes by which to deny access upon output.
Command
Description
Use the bridge-group output-lsap-list interface configuration command to filter IEEE 802-encapsulated packets on output. Use the no form of this command to disable this capability.
bridge-group bridge-group output-lsap-list access-list-number
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. access-list-number Access list number you assigned with the standard access-list command. Specify a zero (0) to disable the application of the access list on the bridge group.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
SNAP frames must also pass any applicable Ethernet type-code access list. This access list is applied just before sending out a frame to an interface.
For performance reasons, specify both input and output type code filtering on the same interface.
Access lists for Ethernet- and IEEE 802-encapsulated packets affect only bridging functions. It is not possible to use such access lists to block frames with protocols that are being routed.
Packets bearing an 802.2 LSAP of 0xAAAA qualify for LSAP filtering since they are inherently in 802.3 format. However, because they also carry a Type field, they are matched against any Type filters. Therefore, if you use LSAP filters on an interface that may bear SNAP encapsulated packets you must explicitly permit 0xAAAA.
Examples
The following example specifies access list 204 on Ethernet interface 0:
interface ethernet 0 bridge-group 4 output-lsap-list 204
Related Commands
Establishes MAC address access lists. Assigns each network interface to a bridge group. Filters IEEE 802.2-encapsulated packets on input.
Command
Description
Use the bridge-group output-pattern-list interface configuration command to associate an extended access list with a particular interface. Use the no form of this command to disable this capability.
bridge-group bridge-group output-pattern-list access-list-number
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. access-list-number Extended access list number you assigned using the extended access-list command. Specify a zero (0) to disable the application of the access list on the interface.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
Examples
The following example filters all packets sent by bridge group 3 using the filter defined in access-list 1102:
interface ethernet 0 bridge-group 3 output-pattern-list 1102
Related Commands
Establishes MAC address access lists. Assigns each network interface to a bridge group. Associates an extended access list with a particular interface in a particular bridge group.
Command
Description
Use the bridge-group output-type-list interface configuration command to filter Ethernet- and SNAP-encapsulated packets on output. Use the no form of this command to disable this capability.
bridge-group bridge-group output-type-list access-list-number
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. access-list-number Access list number you assigned with the standard access-list command. Specify a zero (0) to disable the application of the access list on the bridge group. This access list is applied just before sending out a frame to an interface.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Autonomous bridging must be disabled to use this command.
Examples
The following example specifies access-list 202 on Ethernet interface 0:
interface ethernet 0 bridge-group 2 output-type-list 202
Related Commands
Establishes MAC address access lists. Assigns each network interface to a bridge group. Filters Ethernet- and SNAP-encapsulated packets on input.
Command
Description
Use the bridge-group path-cost interface configuration command to set a different path cost. Use the no form of this command to choose the default path cost for the interface.
bridge-group bridge-group path-cost cost
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. cost Path cost can range from 1 to 65535, with higher values indicating higher costs. This range applies regardless of whether the IEEE or Digital Spanning-Tree Protocol has been specified.
Defaults
The default path cost is computed from the interface's bandwidth setting. The following are IEEE default path cost values. The Digital path cost default values are different.
Ethernet—100
16-Mb Token Ring—62
FDDI—10
HSSI—647
MCI/SCI Serial—647
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
By convention, the path cost is 10000/data rate of the attached LAN (IEEE), or 100000/data rate of the attached LAN (Digital), in megabits per second.
Examples
The following example changes the default path cost for Ethernet interface 0:
interface ethernet 0 bridge-group 1 path-cost 250
Related Commands
Assigns each network interface to a bridge group.
Command
Description
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63. number Priority number ranging from 0 to 255 (Digital), or 0 to 64000 (IEEE).
Defaults
When the IEEE Spanning-Tree Protocol is enabled on the router: 32768
When the Digital Spanning-Tree Protocol is enabled on the router: 128
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
The lower the number, the more likely it is that the bridge on the interface will be chosen as the root.
Examples
The following example increases the likelihood that the root bridge will be the one on Ethernet interface 0 in bridge group 1:
interface ethernet 0 bridge-group 1 priority 0
Related Commands
Assigns each network interface to a bridge group. Configures the priority of an individual bridge, or the likelihood that it will be selected as the root bridge.
Command
Description
Use the bridge-group spanning-disabled interface configuration command to disable the spanning tree on a given interface.
bridge-group bridge-group spanning-disabled
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range of 1 to 63.
Defaults
Spanning tree enabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
To enable transparent bridging on an interface, use the bridge protocol command to specify the type of Spanning-Tree Protocol to be used. The bridge-group spanning-disabled command can be used to disable that spanning tree on that interface.
When a loop-free path exists between any two bridged subnetworks, you can prevent BPDUs generated in one transparent bridging subnetwork from impacting nodes in the other transparent bridging subnetwork, yet still permit bridging throughout the bridged network as a whole.
For example, when transparently bridged LAN subnetworks are separated by a WAN, you can use this command to prevent BPDUs from traveling across the WAN link. You would apply this command to the serial interfaces connecting to the WAN in order to prevent BPDUs generated in one domain from impacting nodes in the remote domain. Because these BPDUs are prevented from traveling across the WAN link, using this command also has the secondary advantage of reducing traffic across the WAN link.
|
Note In order to disable the spanning tree, you must make sure that no parallel paths exist between transparently bridged interfaces in the network. |
Examples
In the following example, the spanning tree for the serial interface 0 is disabled:
interface serial 0 bridge-group 1 spanning-disabled
Related Commands
Assigns each network interface to a bridge group. Defines the type of STP.
Command
Description
Use the bridge-group sse interface configuration command to enable Cisco's silicon switching engine (SSE) switching function. Use the no form of this command to disable SSE switching.
bridge-group bridge-group sse
Syntax Description
bridge-group Number of the bridge group to which the interface belongs. It must be a number in the range 1 to 63.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Examples
The following example enables SSE switching:
bridge-group 1 sse
Related Commands
source-bridge Configures an interface for SRB.
Command
Description
To specify that an interface is at the upstream point of traffic flow, use the bridge-group subscriber-trunk interface configuration command. Use the no form of this command to remove the specification and reset the interface to a nontrunking port.
bridge-group bridge-group subscriber-trunk
Syntax Description
bridge-group Bridge group number, in the range from 1 to 256, specified in the bridge protocol command.
Defaults
The interface is set to a nontrunking port.
Command Modes
Interface configuration
Command History
11.3 This command was introduced.
Release
Modification
Examples
The following example sets bridge-group 1 as the upstream point of traffic flow:
bridge-group 1 subscriber-trunk
Related Commands
Defines the type of STP. Binds a bridge group with a subscriber policy. Displays the details of a subscriber policy. Defines or modifies the forward and filter decisions of the subscriber policy.
Command
Description
Use the bridge hello-time global configuration command to specify the interval between hello bridge protocol data units (BPDUs). Use the no form of this command to return the default interval.
bridge bridge-group hello-time seconds
Syntax Description
bridge-group Bridge group number. It must be the same number specified in the seconds Interval between 1 and 10 seconds.
bridge protocol command.
Defaults
1 second
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Each bridge in a spanning tree adopts the hello-time, forward-time, and max-age parameters of the root bridge, regardless of what its individual configuration might be.
Examples
The following example sets the interval to 5 seconds:
bridge 1 hello-time 5
Related Commands
Specifies the forward delay interval for the Cisco IOS software. Changes the interval the bridge will wait to hear BPDUs from the root bridge. If a bridge does not hear BPDUs from the root bridge within this specified interval, it assumes that the network has changed and will recompute the spanning-tree topology. Defines the type of STP.
Command
Description
Use the bridge irb global configuration command to enable the Cisco IOS software to route a given protocol between routed interfaces and bridge groups or to route a given protocol between bridge groups. Use the no form of this command to disable the feature.
bridge irbSyntax Description
This command has no arguments or keywords.
Defaults
Integrated routing and bridging (IRB) is disabled.
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
IRB is supported for transparent bridging, but not for source-route bridging. IRB is supported on all interface media types except X.25 and ISDN bridged interfaces.
Examples
The following example enables integrated routing and bridging:
bridge irb
Related Commands
Enables the bridging of a specified protocol in a specified bridge group. Enables the routing of a specified protocol in a specified bridge group. Creates the BVI that represents the specified bridge group to the routed world and links the corresponding bridge group to the other routed interfaces. Displays the configuration for each interface that has been configured for integrated routing or bridging.
Command
Description
Use the bridge lat-service-filtering global configuration command to specify LAT group-code filtering. Use the no form of this command to disable the use of LAT service filtering on the bridge group.
bridge bridge-group lat-service-filtering
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command.
Defaults
LAT service filtering is disabled.
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
This command informs the system that LAT service advertisements require special processing.
Examples
The following example specifies that LAT service announcements traveling across bridge group 1 require some special processing:
bridge 1 lat-service-filtering
Related Commands
Defines the type of STP.
Command
Description
Use the bridge max-age global configuration command to change the interval the bridge will wait to hear BPDUs from the root bridge. If a bridge does not hear BPDUs from the root bridge within this specified interval, it assumes that the network has changed and will recompute the spanning-tree topology. Use the no form of this command to return the default interval.
bridge bridge-group max-age seconds
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command. seconds Interval the bridge will wait to hear BPDUs from the root bridge. It must be a value in the range 10 to 200 seconds.
Defaults
15 seconds
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Each bridge in a spanning tree adopts the hello-time, forward-time, and max-age parameters of the root bridge, regardless of what its individual configuration might be.
Examples
The following example increases the maximum idle interval to 20 seconds:
bridge 1 max-age 20
Related Commands
Specifies the forward delay interval for the Cisco IOS software. Specifies that an interface is at the upstream point of traffic flow. Defines the type of STP.
Command
Description
Use the bridge multicast-source global configuration command to configure bridging support to allow the forwarding, but not the learning, of frames received with multicast source addresses. Use the no form of this command to disable this function on the bridge.
bridge bridge-group multicast-source
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command.
Defaults
Disabled
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
If you need to bridge Token Ring over another medium, RSRB is recommended.
Examples
The following example allows the forwarding, but not the learning, of frames received with multicast source addresses:
bridge 2 multicast-source
Related Commands
Defines the type of STP.
Command
Description
Use the bridge priority global configuration command to configure the priority of an individual bridge, or the likelihood that it will be selected as the root bridge.
bridge bridge-group priority number
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command. number The lower the number, the more likely the bridge will be chosen as root. When the IEEE Spanning-Tree Protocol is enabled, number ranges from 0 to 65535 (default is 32768). When the Digital Spanning-Tree Protocol is enabled, number ranges from 0 to 255 (default is 128).
Defaults
When the IEEE Spanning-Tree Protocol is enabled on the router: 32768
When the Digital Spanning-Tree Protocol is enabled on the router: 128
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
When two bridges tie for position as the root bridge, an interface priority determines which bridge will serve as the root bridge. Use the bridge-group priority interface configuration command to control an interface priority.
Examples
The following example establishes this bridge as a likely candidate to be the root bridge:
bridge 1 priority 100
Related Commands
Sets an interface priority. The interface priority is used to select the designated port for this bridge group on the connected media. One designated port on each medium is needed to compute the spanning tree. Defines the type of STP.
Command
Description
Use the bridge protocol global configuration command to define the type of Spanning-Tree Protocol. Use the no form of this command with the appropriate keywords and arguments to delete the bridge group.
bridge bridge-group protocol {ieee | dec}
Syntax Description
bridge-group Number in the range 1 to 63 that you choose to refer to a particular set of bridged interfaces. Frames are bridged only among interfaces in the same group. You will use the group number you assign in subsequent bridge configuration commands. ieee dec
Defaults
No Spanning-Tree Protocol is defined.
Command Modes
Global configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
The routers support two Spanning-Tree Protocols: the IEEE 802.1 standard and the earlier Digital Spanning-Tree Protocol upon which the IEEE standard is based. Multiple domains are supported for the IEEE 802.1 Spanning-Tree Protocol.
|
Note The IEEE 802.1D Spanning-Tree Protocol is the preferred way of running the bridge. Use the Digital Spanning-Tree Protocol only for backward compatibility. |
Examples
The following example shows bridge 1 as using the Digital Spanning-Tree Protocol:
bridge 1 protocol dec
Related Commands
Establishes a domain by assigning it a decimal value from 1 to 10. Assigns each network interface to a bridge group.
Command
Description
Use the bridge route global configuration command to enable the routing of a specified protocol in a specified bridge group. Use the no form of this command to disable the routing of a specified protocol in a specified bridge group.
bridge bridge-group route protocol
Syntax Description
bridge-group Bridge-group number. It must be the same number specified in the bridge protocol command. protocol One of the following protocols: apollo, appletalk, clns, decnet, ip, ipx, vines, xns.
Defaults
No default bridge group or protocol is specified.
Command Modes
Global configuration
Command History
10.3 This command was introduced.
Release
Modification
Examples
In the following example, AppleTalk and IP are routed on bridge group 1:
bridge crb bridge 1 protocol ieee bridge 1 route appletalk bridge 1 route ip
Related Commands
Enables the Cisco IOS software to both route and bridge a given protocol on separate interfaces within a single router. Defines the type of STP.
Command
Description
To bind a bridge group with a subscriber policy, use the bridge subscriber-policy global configuration command. Use the no form of this command to disable the subscriber bridge group feature.
bridge bridge-group subscriber-policy policy
Syntax Description
bridge-group Bridge group number, in the range of 1 to 256, specified in the bridge protocol command. policy Subscriber policy number in the range of 1 to 100.
Defaults
If no forward or filter decisions have been specified for the subscriber policy, the following defaults are applied:
Packet | Upstream |
|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
Command Modes
Global configuration
Command History
11.3 This command was introduced.
Release
Modification
Usage Guidelines
Standard access lists can coexist with the subscriber policy. However, subscriber policy will take precedence over the access list by being checked first. A packet permitted by the subscriber policy will be checked against the access list if it is specified. A packet denied by subscriber policy will be dropped with no further access list checking.
Examples
The following example forms a subscriber bridge group using policy 1:
bridge 1 subscriber-policy 1
Related Commands
Defines the type of STP. Displays the details of a subscriber policy. Defines or modifies the forward and filter decisions of the subscriber policy.
Command
Description
Use the clear bridge privileged EXEC command to remove any learned entries from the forwarding database and to clear the transmit and receive counts for any statically or system configured entries.
clear bridge bridge-group
Syntax Description
bridge-group Bridge group number specified in the bridge protocol command.
Command Modes
Privileged EXEC
Command History
10.0 This command was introduced.
Release
Modification
Examples
The following example shows the use of the clear bridge command:
clear bridge 1
Related Commands
Filters frames with a particular MAC-layer station source or destination address. Defines the type of STP.
Command
Description
Use the clear bridge multicast EXEC command to clear transparent bridging multicast state information.
clear bridge [bridge-group] multicast [router-ports | groups | counts] [group-address] [interface-unit] [counts]
Syntax Description
bridge-group (Optional) Bridge group number specified in the bridge protocol command. router-ports (Optional) Clear multicast router ports. groups (Optional) Clear multicast groups. counts (Optional) Clear RX and TX counts. group-address (Optional) Multicast IP address associated with a specific multicast group. interface-unit (Optional) Specific interface, such as Ethernet 0.
Command Modes
EXEC
Command History
11.2 This command was introduced.
Release
Modification
Usage Guidelines
If you do not specify arguments or keywords as part of the command, the command clears router ports, group ports, and counts for all configured bridge groups.
Use the show bridge multicast command to list transparent bridging multicast state information, then use specific pieces of state information in the clear bridge multicast command.
Examples
The following example clears router ports, group ports, and counts for bridge group 1:
clear bridge 1 multicast
The following example clears the group and count information for the group identified as 235.145.145.223, interface Ethernet 0/3 for bridge group 1:
clear bridge 1 multicast groups 235.145.145.223 Ethernet0/3 counts
Related Commands
Enables CMF for all configured bridge groups. Displays transparent bridging multicast state information.
Command
Description
Use the clear vlan statistics privileged EXEC command to remove virtual LAN statistics from any statically or system configured entries.
clear vlan statisticsSyntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Command History
11.2 This command was introduced.
Release
Modification
Examples
The following example clears VLAN statistics:
clear vlan statistics
Use the frame-relay map bridge broadcast interface configuration command to bridge over a Frame Relay network. Use the no form of this command to delete the mapping entry.
frame-relay map bridge dlci broadcast
Syntax Description
dlci DLCI number. The valid range is 16 to 1007.
Defaults
No mapping entry is established.
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
Bridging over a Frame Relay network is supported both on networks that support a multicast facility and those that do not.
Examples
The following example allows bridging over a Frame Relay network:
frame-relay map bridge 144 broadcast
Related Commands
encapsulation frame-relay Enables Frame Relay encapsulation.
Command
Description
Use the interface bvi interface configuration command to create the bridge-group virtual interface (BVI) that represents the specified bridge group to the routed world and links the corresponding bridge group to the other routed interfaces. Use the no form of this command to delete the BVI.
interface bvi bridge-group
Syntax Description
bridge-group Bridge-group number. It must be the same number specified in the bridge protocol command.
Defaults
No BVI is created.
Command Modes
Interface configuration
Command History
11.2 This command was introduced.
Release
Modification
Usage Guidelines
You must enable IRB before attempting to create a BVI.
When you intend to bridge and route a given protocol in the same bridge group, you must configure the network-layer attributes of the protocol on the BVI. Do not configure protocol attributes on the bridged interfaces. No bridging attributes can be configured on the BVI.
Examples
The following example creates a bridge-group virtual interface and associates it with bridge group 1:
interface bvi 1
Related Commands
Enables the Cisco IOS software to route a given protocol between routed interfaces and bridge groups or to route a given protocol between bridge groups.
Command
Description
Use the show bridge privileged EXEC command to view classes of entries in the bridge forwarding database.
show bridge [bridge-group] [interface] [address [mask]] [verbose]
Syntax Description
bridge-group (Optional) Number that specifies a particular spanning tree. interface (Optional) Specific interface, such as Ethernet 0. address (Optional) 48-bit canonical (Ethernet ordered) MAC address. This may be entered with an optional mask of bits to be ignored in the address, which is specified with the mask argument. mask (Optional) Bits to be ignored in the address. You must specify the address argument if you want to specify a mask. verbose (Optional) Shows additional detail, including any Frame Relay DLCI associated with a station address.
Command Modes
Privileged EXEC
Command History
10.0 This command was introduced. 11.0 The verbose keyword was added.
Release
Modification
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0. The verbose keyword first appeared in
Cisco IOS Release 11.0.
The following are possible variations of the show bridge command:
show bridge ethernet 0 show bridge 0000.0c00.0000 0000.00FF.FFFF show bridge 0000.0c00.0e1a show bridge show bridge verbose
In the sample output, the first command would display all entries for hosts reachable via Ethernet interface 0, the second command would display all entries with the vendor code of 0000.0c00.0000, and the third command would display the entry for address 0000.0c00.0e1a. In the fourth command, all entries in the forwarding database would be displayed. The fifth command provides additional detail. In all five lines, the bridge-group number has been omitted.
Examples
The following is sample output from the show bridge command. The second display is output from the
show bridge command with the verbose argument.
Router# show bridge
Total of 300 station blocks, 280 free
Codes: P - permanent, S - self
Bridge Group 32:Bridge Group 32:
Address Action Interface Age RX count TX count
0180.c200.0000 receive - S 0 0
ffff.ffff.ffff receive - S 0 0
0900.2b01.0001 receive - S 0 0
0300.0c00.0001 receive - S 0 0
0000.0c05.1000 forward Ethernet0/1 4 1 0
0000.0c04.4b5b receive - S 0 0
0000.0c04.4b5e receive - S 0 0
0000.0c04.4b5d receive - S 0 0
0000.0c04.4b5c receive - S 0 0
0000.0c05.4a62 forward Ethernet0/1 4 1 0
aa00.0400.2108 forward Ethernet0/1 0 42 0
0000.0c12.b888 forward Ethernet0/2 4 1 0
0000.0c12.b886 forward Ethernet0/1 4 1 0
aa00.0400.4d09 forward Ethernet0/1 4 1 0
0000.0c06.fb9a forward Ethernet0/1 4 1 0
0000.0c04.b039 forward Ethernet0/1 4 1 0
router# show bridge verbose
Total of 300 station blocks, 287 free
Codes: P - permanent, S - self
BG Hash Address Action Interface DLCI Age RX count TX count
32 00/0 0180.c200.0000 receive - - S 0 0
32 00/1 ffff.ffff.ffff receive - - S 0 0
32 01/0 0900.2b01.0001 receive - - S 0 0
32 01/1 0300.0c00.0001 receive - - S 0 0
32 10/0 0000.0c04.4b5b receive - - S 0 0
32 15/0 0000.0c04.4b5e receive - - S 0 0
32 16/0 0000.0c04.4b5d receive - - S 0 0
32 17/0 0000.0c04.4b5c receive - - S 0 0
32 29/0 aa00.0400.2108 forward Ethernet0/1 - 0 48 0
32 30/0 0000.0c12.b888 forward Ethernet0/2 - 0 1 0
32 A4/0 0800.2002.ff5b forward Ethernet0/1 - 0 6 0
32 E2/0 aa00.0400.e90b forward Ethernet0/1 - 0 65 0
32 F2/0 0000.0c04.b042 forward Ethernet0/2 - 3 2 0
Table 4 describes significant fields shown in the display
.
| Field | Description |
|---|---|
Total of 300 station blocks | Total number of forwarding database elements in the system. The memory to hold bridge entries is allocated in blocks of memory sufficient to hold 300 individual entries. When the number of free entries falls below 25, another block of memory sufficient to hold another 300 entries is allocated. Therefore, the size of the bridge forwarding database is limited to the amount of free memory in the router. |
295 free | Number in the free list of forwarding database elements in the system. The total number of forwarding elements is expanded dynamically, as needed. |
BG | Bridging group to which the address belongs. |
Hash | Hash key/relative position in the keyed list. |
Address | Canonical (Ethernet ordered) MAC address. |
Action | Action to be taken when that address is looked up; choices are to discard or forward the datagram. |
Interface | Interface, if any, on which that address was seen. |
Age | Number of minutes since a frame was received from or sent to that address. The letter "P" indicates a permanent entry. The letter "S" indicates the system as recorded by the router. On the modular systems, this is typically the broadcast address and the router's own hardware address; on the IGS, this field will also include certain multicast addresses. |
RX count | Number of frames received from that address. |
TX count | Number of frames forwarded to that address. |
Syntax Description
bridge-group (Optional) Number that specifies a particular bridge group. circuit-group (Optional) Number that specifies a particular circuit group. src-mac-address (Optional) 48-bit canonical (Ethernet ordered) source MAC address. dst-mac-address (Optional) 48-bit canonical (Ethernet ordered) destination MAC address.
Command Modes
EXEC
Command History
10.3 This command was introduced.
Release
Modification
Examples
The following is sample output from various show bridge circuit-group command strings:
RouterA> show bridge circuit-group Bridge group 1 Circuit group 1: Interface Serial0 : inserted, learning, forwarding Interface Serial3 : inserted, learning, forwarding Bridge group 1 Circuit group 2: Interface Serial2 : inserted, learning, forwarding RouterA> show bridge 1 circuit-group 1 Bridge group 1 Circuit group 1: Interface Serial0 : inserted, learning, forwarding Interface Serial3 : inserted, learning, forwarding RouterA> show bridge 1 circuit-group 2 Bridge group 1 Circuit group 2: Interface Serial2 : inserted, learning, forwarding RouterA> show bridge 1 circuit-group 1 0000.6502.23EA 0000.1234.4567 Output circuit group interface is Serial3 RouterA> show bridge 1 circuit-group 1 0000.6502.23EA %Destination MAC address required RouterB> show bridge 1 circuit-group 1 Bridge group 1 Circuit group 1: Transmission pause interval is 250ms Output interface selection is source-based Interface Serial0 : inserted, learning, forwarding Interface Serial3 : inserted, learning, forwarding Interface Serial2 is unavailable RouterB> show bridge 1 circuit-group 1 0000.6502.23EA 0000.1234.4567 %Please enter source MAC address only
Table 5 describes significant fields shown in the display.
| Field | Description |
inserted/not inserted | Indicates whether interface is included or not included in circuit-group operation. If the interface is administratively down, or if line protocol is not up, the interface is not included in the circuit-group operation. |
learning/not learning | Indicates whether this interface is in Spanning-Tree Protocol (IEEE or Digital) learning or not learning state. |
forwarding/not forwarding | Indicates whether this port is in Spanning-Tree Protocol (IEEE or Digital) forwarding or not forwarding state. |
Use the show bridge group privileged EXEC command to display the status of each bridge group.
show bridge group [verbose]
Syntax Description
verbose (Optional) Displays detailed information.
Command Modes
Privileged EXEC
Command History
10.3 This command was introduced.
Release
Modification
Examples
The following is sample output from the show bridge group command:
Router# show bridge group Bridge Group 1 is running the DEC compatible Spanning Tree protocol Port 7 (ATM0.1 LANE Ethernet) of bridge group 1 is down Port 4 (TokenRing0) of bridge group 1 is forwarding
"Forwarding" and "down" indicate the port state as determined by the spanning-tree algorithm or via configuration.
Use the show bridge multicast EXEC command to display transparent bridging multicast state information.
show bridge [bridge-group] multicast [router-ports | groups] [group-address]
Syntax Description
bridge-group (Optional) Bridge group number specified in the bridge protocol command. router-ports (Optional) Display information for multicast router ports. groups (Optional) Display information for multicast groups. group-address (Optional) Multicast IP address associated with a specific multicast group.
Command Modes
EXEC
Command History
11.2 This command was introduced.
Release
Modification
Examples
The following is sample output from the show bridge multicast command:
Router# show bridge multicast Multicast router ports for bridge group 1: 2 multicast router ports Fddi2/0 R Ethernet0/4 R Multicast groups for bridge group 1: 235.145.145.223 RX count TX count Fddi2/0 R 0 2 Ethernet0/4 R 0 3 Ethernet0/3 G 1 0 235.5.5.5 RX count TX count Fddi2/0 R 0 2 Ethernet0/4 R 0 3 Ethernet0/3 G 1 0 235.4.4.4 RX count TX count Fddi2/0 R 0 2 Ethernet0/4 R 0 3 Ethernet0/3 G 1 0
Table 6 describes significant fields shown in the display.
| Field | Description |
|---|---|
Multicast router ports for | List of the multicast router ports by bridge group. Within the bridge group cluster, the display lists the number of multicast router ports and then lists the ports by interface. |
Multicast groups for | List of the multicast groups by bridge group. Within each multicast group, identified by a unique address, the display lists each port by interface name and indicates whether that port is a group member ("G"), a multicast router port ("R"), or both. The RX and TX counts show the number of multicast packets that have constrained to the multicast group by the bridge. |
Use the show bridge vlan privileged EXEC command to view virtual LAN subinterfaces.
show bridge vlanSyntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Command History
10.3 This command was introduced.
Release
Modification
Examples
The following is sample output from the show bridge vlan command:
Router# show bridge vlan Bridge Group: 50 Virtual LAN Trunking Interface(s): vLAN Protocol: vLAN ID: State Fddi2/0.1000 IEEE 802.10 1000 forwarding FastEthernet4/0.500 Inter Switch Link 500 listening Virtual LAN Native Interface(s): State Ethernet0/1 forwarding Serial1/1 down
Table 7 describes the fields shown in the display.
| Field | Description |
|---|---|
Bridge Group | Bridge group to which these interfaces belong. |
Virtual LAN Trunking Interface(s) | VLAN interface. |
vLAN Protocol) | IEEE 802.10 or Cisco ISL encapsulation. |
vLAN ID | VLAN identifier that maintains VLAN identities between switches. |
State | Spanning-tree port state of the interface. |
Virtual LAN Native Interface(s): | Interfaces whose transparently bridged traffic will be propagated only to other LAN segments within the same virtual LAN. |
Use the show interfaces crb privileged EXEC command to display the configuration for each interface that has been configured for routing or bridging.
show interfaces crbSyntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Command History
11.0 This command was introduced.
Release
Modification
Examples
The following is sample output from the show interfaces crb command: Router# show interfaces crb Ethernet0/0 Routed protocols on Ethernet0/0: appletalk decnet ip novell Ethernet0/1 Routed protocols on Ethernet0/1: appletalk decnet ip novell Ethernet0/2 Routed protocols on Ethernet0/2: appletalk ip Bridged protocols on Ethernet0/2: clns decnet vines apollo novell xns Software MAC address filter on Ethernet0/2 Hash Len Address Matches Act Type 0x00: 0 ffff.ffff.ffff 0 RCV Physical broadcast 0x00: 1 ffff.ffff.ffff 0 RCV Appletalk zone 0x2A: 0 0900.2b01.0001 0 RCV DEC spanning tree 0x49: 0 0000.0c36.7a45 0 RCV Interface MAC address 0xc0: 0 0100.0ccc.cccc 20 RCV CDP 0xc2: 0 0180.c200.0000 0 RCV IEEE spanning tree 0xF8: 0 0900.07ff.ffff 0 RCV Appletalk broadcast Ethernet0/3 Routed protocols on Ethernet0/3: appletalk ip Bridged protocols on Ethernet0/3: clns decnet vines apollo novell xns Software MAC address filter on Ethernet0/3 Hash Len Address Matches Act Type 0x00: 0 ffff.ffff.ffff 0 RCV Physical broadcast 0x00: 1 ffff.ffff.ffff 0 RCV Appletalk zone 0x2A: 0 0900.2b01.0001 0 RCV DEC spanning tree 0x49: 0 0000.0c36.7a45 0 RCV Interface MAC address 0xc0: 0 0100.0ccc.cccc 48 RCV CDP 0xc2: 0 0180.c200.0000 0 RCV IEEE spanning tree 0xF8: 0 0900.07ff.ffff 0 RCV Appletalk broadcast
Table 8 describes significant fields shown in the display.
| Field | Description |
|---|---|
Routed protocols on | List of the routed protocols configured for the specified interface. |
Bridged protocols on | List of the bridged protocols configured for the specified interface. |
Software MAC address filter on | Table of software MAC address filter information for the specified interface. |
Hash | Hash key/relative position in the keyed list for this MAC-address entry. |
Len | Length of this entry to the beginning element of this hash chain. |
Address | Canonical (Ethernet ordered) MAC address. |
Matches | Number of received packets matched to this MAC address. |
Act | Action to be taken when that address is looked up; choices are to receive or discard the packet. |
Type | MAC address type. |
Use the show interfaces irb privileged EXEC command to display the configuration for each interface that has been configured for integrated routing or bridging.
show interfaces [interface] irb
Syntax Description
interface (Optional) Specific interface, such as Ethernet 0.
Command Modes
Privileged EXEC
Command History
11.2 This command was introduced.
Release
Modification
Examples
The following is sample output from the show interfaces irb command:
Router# show interfaces ethernet 2 irb Ethernet 2 Routed protocols on Ethernet 2: appletalk ip Bridged protocols on Ethernet 2: appletalk clns decnet vines apollo ipx xns Software MAC address filter on Ethernet 2 Hash Len Address Matches Act Type 0x00: 0 ffff.ffff.ffff 4886 RCV Physical broadcast 0x1F: 0 0060.3e2b.a221 7521 RCV Appletalk zone 0x1F: 1 0060.3e2b.a221 0 RCV Bridge-group Virtual Interface 0x2A: 0 0900.2b01.0001 0 RCV DEC spanning tree 0x05: 0 0900.0700.00a2 0 RCV Appletalk zone 0xC2: 0 0180.c200.0000 0 RCV IEEE spanning tree 0xF8: 0 0900.07ff.ffff 2110 RCV Appletalk broadcast
Table 9 describes significant fields shown in the display.
| Field | Description |
|---|---|
Routed protocols on | List of the routed protocols configured for the specified interface. |
Bridged protocols on | List of the bridged protocols configured for the specified interface. |
Software MAC address filter on | Table of software MAC address filter information for the specified interface. |
Hash | Hash key/relative position in the keyed list for this MAC-address entry. |
Len | Length of this entry to the beginning element of this hash chain. |
Address | Canonical (Ethernet ordered) MAC address. |
Matches | Number of received packets matched to this MAC address. |
Act | Action to be taken when that address is looked up; choices are to receive or discard the packet. |
Type | MAC address type. |
To display the details of a subscriber policy, use the show subscriber-policy EXEC command.
show subscriber-policy range
Syntax Description
range Range of subscriber policy numbers (range 1 to 100).
Command Modes
EXEC
Examples
The following is sample output from the show subscriber-policy command:
Router# show subscriber-policy 1 ARP: Permit Broadcast: Deny Multicast: Permit Unknown: Deny STP: Disable CDP: Disable
Related Commands
Defines the type of STP. Binds a bridge group with a subscriber policy. Displays classes of entries in the bridge forwarding database. Defines or modifies the forward and filter decisions of the subscriber policy.
Command
Description
To define or modify the forward and filter decisions of the subscriber policy, use the subscriber-policy global configuration command. Use the no or default form of this command to restore the default forward and filter values.
subscriber-policy policy [[no | default] packet [permit | deny]]
Syntax Description
policy Subscriber policy number in the range 1 to 100. no (Optional) Turn off the permit for the packet (this is an equivalent of the deny keyword). default (Optional) Deny forwarding of the packet (this is an equivalent of the deny keyword). packet One of the following packets: permit (Optional) Permit forwarding of the packet. deny (Optional) Deny forwarding of the packet.
Defaults
If no forward or filter decisions have been specified for the subscriber policy, the following defaults are applied:
Packet | Upstream |
|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
Command Modes
Global configuration
Command History
11.3 This command was introduced.
Release
Modification
Usage Guidelines
As an alternative to the command syntax described above, you can enter subscriber-policy policy, followed by the specific forward or filter decisions for each packet.
Examples
The following example changes the ARP behavior and the multicast behavior from permit to deny, using the command syntax shown in the Command Syntax section:
subscriber-policy 3 arp deny subscriber-policy 3 multicast deny
The following example changes the ARP behavior and the multicast behavior from permit to deny, using the alternative syntax shown in the Usage Guidelines section:
subscriber-policy 3 arp deny multicast deny
Related Commands
Defines the type of STP. Binds a bridge group with a subscriber policy. Displays the details of a subscriber policy.
Command
Description
Use the show vlans privileged EXEC command to view virtual LAN subinterfaces.
show vlansSyntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Command History
11.0 This command was introduced.
Release
Modification
Examples
The following is sample output from the show vlans command:
RouterC7xxx# show vlans Virtual LAN ID: 300 (IEEE 802.10 Encapsulation) vLAN Trunk Interface: FDDI 1/1.10 Protocols Configured: Address: Received: Transmitted: IP 31.108.1.1 642 645 Virtual LAN ID: 400 (ISL Encapsulation) vLAN Trunk Interface: FastEthernet 2/1.20 Protocols Configured: Address: Received: Transmitted: IP 171.69.2.2 123456 654321 Bridge Group 50 5190 8234 Virtual LAN ID: 500 (ISL Encapsulation) vLAN Trunk Interface: FastEthernet 2/1.30 Protocols Configured: Address: Received: Transmitted: IPX 1000 987654 456789 Virtual LAN ID: 600 (ISL Encapsulation) vLAN Trunk Interface: FastEthernet 2/1.30 Protocols Configured: Address: Received: Transmitted: IP 198.92.3.3 8114 4508 IPX 1001 2 3 Bridge Group 50 8234 5190
Table 10 describes the fields shown in the display.
| Field | Description |
|---|---|
Virtual LAN ID | The domain number of the virtual LAN. |
vLAN Trunk Interface | The subinterface that carries the VLAN traffic. |
Protocols Configured | The protocols configured on the VLAN. |
Address | The network address. |
Received | Packets received. |
Transmitted | Packets transmitted. |
Use the x25 map bridge interface configuration command to configure the bridging of packets in X.25 frames. Use the no form of this command to disable the Internet-to-X.121 mapping.
x25 map bridge x.121-address broadcast [options-keywords]
Syntax Description
x.121-address The X.121 address. broadcast Required keyword for bridging over X.25. options-keywords (Optional) Additional functionality that can be specified for originated calls. Can be any of the options listed in Table 11.
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0 This command was introduced.
Release
Modification
Usage Guidelines
The X.25 bridging software uses the same spanning-tree algorithm as the other bridging functions, but allows packets to be encapsulated in X.25 frames and transmitted across X.25 media. This command specifies IP-to-X.121 address mapping and maintains a table of both the Ethernet and X.121 addresses.
The X.25 bridging implementation supports the map options listed in Table 11.
Examples
The following example allows bridging over an X.25 network:
x25 map bridge 31370054065 broadcast
Related Commands
x25 address Sets the X.121 address of a particular network interface. x25 map Sets up the LAN protocols-to-remote host mapping.
Command
Description
Posted: Wed Aug 23 07:15:57 PDT 2000
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