Networking Protocol Configurations

This chapter describes networking protocol configurations for your switch router. It provides initial configuration information so you can get your switch router up and running. For more information about the Cisco IOS commands used in this chapter, refer to the Cisco IOS command references. This chapter includes the following sections:

Note You are at step 4 in the suggested process for configuring your switch router (see Table 2-1). You should have already completed general interface configurations, and are ready to proceed with configuring networking and routing protocols.

About IP Routing Protocols

This section briefly describes how to configure the switch router for supported IP routing protocols. It is intended to provide enough information for a network administrator to get the protocols up and running. However, this section does not provide in-depth configuration detail for each protocol. For detailed information, refer to any of the protocol configuration guides in the public domain.

IP routing is enabled by default on the switch router. For IP routing, make the following configurations for the interface:

a network address
a subnetwork address
an IP subnet mask

The following global configurations are also required:

Select a routing protocol, such as the Enhanced Interior Gateway Routing Protocol (EIGRP) or the Routing Information Protocol (RIP).
Assign IP network numbers without specifying subnet values.

EIGRP saves bandwidth by sending routing updates only when routing information changes. The updates contain only information about the link that changed, not the entire routing table. EIGRP also takes into consideration the available bandwidth when determining the rate at which it transmits updates.

Open Shortest Path First

Open Shortest Path First (OSPF) is a standards-based IP routing protocol designed to overcome the limitations of IP RIP. Because OSPF is a link-state routing protocol, it sends link-state advertisements (LSAs) to all other routers within the same hierarchical area. Information on the attached interfaces and their metrics is used in OSPF LSAs. As routers accumulate link-state information, they use the Shortest Path First (SPF) algorithm to calculate the shortest path to each node. Additional OSPF features include equal-cost multipath routing and routing based on the upper-layer type of service (ToS) requests.

OSPF employs the concept of an area, which is a grouping of contiguous OSPF networks and hosts. OSPF areas are logical subdivisions of OSPF autonomous systems whose internal topology is hidden to routers outside the area. Areas allow an additional level of hierarchy different from that provided by IP network classes, and they can be used to aggregate routing information and mask the details of a network. These features make OSPF particularly scalable to large networks.

Routing Information Protocol

Routing Information Protocol (RIP) is a distance-vector, intradomain routing protocol. RIP works well in small, homogeneous networks. However, in larger, more complex internetworks it has many limitations, such as a maximum hop count of 15, lack of support for variable-length subnet masks (VLSMs), inefficient use of bandwidth, and slow convergence. (RIP II does support VLSMs.)

Note Layer 3 switching does not support the Next Hop Resolution Protocol (NHRP).

Configuring IP Routing Protocols

Table 6-1 shows an example of the Cisco IOS commands used to configure routing protocols to run on a Fast Ethernet interface.

Table 6-1: Configuring Routing Protocols

Step Command Description

1 .

Router(config)# interface fa x/0/z

Router(config-if)#

From global configuration mode, enter Ethernet interface configuration mode to configure a particular Fast Ethernet interface.

2 .

Router(config-if)# ip address ip_address subnet_mask

Assign an IP address and subnet mask to the interface.

3 .

Router(config-if)# exit

Exit interface configuration mode and step back one level to global configuration mode.

4 .

Router(config)# router rip

Router(config-router)#

Use the switch router rip command to define RIP as the routing protocol and start the RIP routing process.

5 .

Router(config-router)# network net_number

Router(config-router)# exit

Router(config)#

The network command specifies a directly connected network based on the Network Information Center (NIC) network number--not a subnet number or individual address. The routing process associates interfaces with the appropriate addresses and begins processing packets on the specified network.

6 .

Router# router igrp autonomous_system_number

Router(config-router)#

Use the router igrp command to define IGRP as the IP routing protocol.

The autonomous system number is the autonomous system to which this switch router belongs.

7 .

Router(config-router) # network net_number

Router(config-router)# exit

Router(config)#

The network command defines the directly connected networks that run IGRP.

8 .

Router(config)# router eigrp autonomous_system_number

Use the router eigrp command to define EIGRP as the IP routing protocol.

The autonomous system number is the autonomous system to which this switch router belongs.

9 .

Router(config-router)# network net_number

Use the network command to define the directly connected networks that run EIGRP.

The network number is the number of the network that is advertised by this switch router.

10 .

Router(config)# router ospf process_ID

Router(config-router)#

Use the router ospf command to define OSPF as the IP routing protocol.

The process ID identifies a unique OSPF router process. This number is internal to the switch router only; the process ID does not have to match the process IDs on other routers.

11 .

Router(config-router)# network net_address | wildcard_mask area area_ID

Router(config-router)# Ctrl-Z

Router#

The network area command is a way of assigning an interface to a specific area.

The network address is the address of directly connected networks or subnets.

The wildcard mask is an inverse mask used to compare a given address with interface addressing to determine whether OSPF will use this interface.

The area parameter identifies the interface as belonging to an area.

The area ID specifies the area associated with the network address.

12 .

Router# copy running-config startup-config

Save your configuration changes to NVRAM.

Verifying IP Operation

Once IP routing is configured, you can monitor and troubleshoot the protocol operation using the commands in Table 6-2.

Table 6-2: Monitoring and Troubleshooting the Protocol Operation

Command Displays

show ip protocol

Values about routing timers and network information associated with the entire router. Use this information to identify a router that is suspected of delivering bad router information.

show ip route

Contents of the IP routing table. The routing table contains entries for all known networks and subnetworks, and contains a code that indicates how that information was learned.

show ip interfaces

The status and global parameters associated with an interface. Cisco IOS automatically enters a directly connected route in the routing table if the interface is one through which a protocol can send and receive packets. Such an interface is marked "up." If the interface is unusable, it is removed from the routing table.

debug ip rip

RIP routing updates as the updates are sent and received.

debug lss ipucast events | errors | reload

Updates sent to the interface module for the IP switching control layer.

Command	Displays
show ip protocol	Values about routing timers and network information associated with the entire router. Use this information to identify a router that is suspected of delivering bad router information.
show ip route	Contents of the IP routing table. The routing table contains entries for all known networks and subnetworks, and contains a code that indicates how that information was learned.
show ip interfaces	The status and global parameters associated with an interface. Cisco IOS automatically enters a directly connected route in the routing table if the interface is one through which a protocol can send and receive packets. Such an interface is marked "up." If the interface is unusable, it is removed from the routing table.
debug ip rip	RIP routing updates as the updates are sent and received.
debug lss ipucast events \| errors \| reload	Updates sent to the interface module for the IP switching control layer.

About IP Multicast Routing

As networks increase in size, multicast routing becomes critically important as a means to determine which segments require multicast traffic and which do not. IP multicast is a routing technique that allows IP traffic to be propagated from one source to a number of destinations, or from many sources to many destinations. Rather than sending one packet to each destination, one packet is sent to the multicast group identified by a single IP destination group address.

IP multicast supports constrained multicast flooding over bridge group virtual interfaces (BVIs), as well as BVIs over Fast EtherChannel. Using constrained multicast flooding, the switch router can dynamically determine group membership of IP multicast groups and flood multicast packets only to those ports where group members reside.

A principle component of IP multicast is the Internet Group Membership Protocol (IGMP). With IGMP, a class D address can dynamically register an individual host in a multicast group. Hosts identify their group membership by sending IGMP messages to the switch router. Traffic is sent to all members of a multicast group. A host can be a member of more than one group at a time. Also, a host does not need to be a member of a group to send data to that group. Enabling Protocol Independent Multicast (PIM) on an interface also enables IGMP operation on that interface.

The routing protocols that the switch router uses to discover multicast groups and build routes for each group follow:

Protocol Independent Multicast (PIM)
Distance Vector Multicast Routing Protocol (DVMRP)
Constrained Multicast Flooding (CMF)

: The Catalyst 8500 supports interoperability with routers configured for DVMRP.

About Protocol Independent Multicast

Protcol Independent Multicast (PIM) includes two different modes of behavior for dense and sparse traffic environments. These are referred to as dense mode and sparse mode.

PIM dense mode assumes that the downstream networks want to receive the datagrams forwarded to them. The switch router forwards all packets on all outgoing interfaces until pruning and truncating occurs.Thus, interfaces with PIM dense mode enabled receive the multicast data stream until it times out. PIM dense mode is most useful under these conditions:

Senders and receivers are in close proximity to each other.
The internetwork has fewer senders than receivers.
The stream of multicast traffic is constant.

PIM sparse mode assumes that the downstream networks do not want to forward multicast packets for a group unless there is an explicit request for the traffic. PIM sparse mode defines a rendezvous point, which is used as a registration point to facilitate the proper routing of packets.

When a sender wants to send data, it first sends the data to the rendezvous point. When a router is ready to receive data, it registers with the rendezvous point. After the data stream begins to flow from the sender to the rendezvous point and then to the receiver, routers in the data path optimize the path by automatically removing any unnecessary hops, including the rendezvous point.

PIM sparse mode is optimized for environments in which there are many multipoint data streams and each multicast stream goes to a relatively small number of LANs in the internetwork. PIM sparse mode is most useful under these conditions:

There are few receivers in the group.
Senders and receivers are separated by WAN links.
The stream of multicast traffic is intermittent.

Configuring IP Multicast Routing

Table 6-3 shows an example of how to configure IP multicast routing.

Table 6-3: Configuring IP Multicast Routing

Step Command Description

1
Router(config)# ip multicast-routing

From global configuration mode, enable IP multicast on the switch router.

2
Router(config)# interface fa x/0/z

Router(config-if)#

Enter Ethernet interface configuration mode to configure the Fast Ethernet interface.

3
Router(config-if)# ip address ip_address subnet_mask

Assign an IP address and subnet mask to the interface.

4
Router(config-if)# ip pim [dense-mode|sparse mode | sparse-dense-mode]

Enter this command on each interface on which you want to run IP multicast routing. Note that you must indicate dense mode, sparse mode, or sparse-dense mode (for internetworks that include both cases).

5
Router(config-if)# Ctrl-Z

Return to privileged EXEC mode.

6
Router# copy running-config startup-config

Save your configuration changes to NVRAM.

Step	Command	Description
1	`Router(config)#` ip multicast-routing	From global configuration mode, enable IP multicast on the switch router.
2	`Router(config)#` interface fa x/0/z `Router(config-if)#`	Enter Ethernet interface configuration mode to configure the Fast Ethernet interface.
3	`Router(config-if)#` ip address ip_address subnet_mask	Assign an IP address and subnet mask to the interface.
4	`Router(config-if)#` ip pim `[`dense-mode`\|`sparse mode `\|` sparse-dense-mode`]`	Enter this command on each interface on which you want to run IP multicast routing. Note that you must indicate dense mode, sparse mode, or sparse-dense mode (for internetworks that include both cases).
5	`Router(config-if)#` Ctrl-Z	Return to privileged EXEC mode.
6	`Router#` copy running-config startup-config	Save your configuration changes to NVRAM.

Verifying IP Multicast Operation

Once IP multicast routing is configured, you can monitor and troubleshoot its operation using the commands in Table 6-4.

Table 6-4: Monitoring and Troubleshooting IP Multicast Operation

Command Displays

show ip mroute

Complete multicast routing table

show ip mroute count

Combined statistics of packets processed by the RP and the Ethernet interface modules

debug lss ipmcast events | errors | reload

Updates sent to the interface module for the IP switching control layer

Command	Displays
show ip mroute	Complete multicast routing table
show ip mroute count	Combined statistics of packets processed by the RP and the Ethernet interface modules
debug lss ipmcast events \| errors \| reload	Updates sent to the interface module for the IP switching control layer

About Novell IPX Protocol

The Cisco implementation of Novell Internetwork Packet Exchange (IPX) protocol provides all of the functionality of a Novell external bridge (Novell refers to their router functionality as bridging).

IPX is a proprietary protocol. Novell IPX can be described as follows:

A datagram, connectionless protocol that does not require an acknowledgment for each packet
A Layer 3 (network) protocol that defines the internetwork and internode addresses
A router specification used to identify the Novell NetWare protocol suite

Novell IPX uses the following protocols and services:

Routing Information Protocol (RIP)--Facilitates the exchange of routing information
NetWare Core Protocol (NCP)--Provides client-to-server connections and applications
Sequenced Packet Exchange (SPX)--Service for Layer 4 (Transport) connection-oriented services
Service Advertising Protocol (SAP)--Advertises NetWare services and addresses, which makes service availability dynamic

Note Layer 3 switching does not support the NetWare Link Services Protocol (NLSP).

About IPX Network Addresses

An IPX network address consists of a network number and a node number, expressed in the format network.node.

Network Number A 4-byte (32-bit) number that identifies the physical network. The network number is expressed in hexadecimal and must be unique throughout the entire IPX internetwork. When configuring an IPX network number, you can omit the leading zeros.

Node Number Identifies a node on the network, represented by dotted triplets of 4-digit hexadecimal numbers. The node number is normally the MAC address of the NetWare node or router interface.

Since both the network number and the host address are needed to deliver traffic to a host, addresses are usually given as network numbers, followed by host addresses, separated with dots, as in the example: 4a.0000.0c00.23fe. In this example, the network number is 4a, and the host address is 0000.0c00.23fe.

The serial interface does not have a MAC address. It uses the default Novell node address, which is the MAC address of the first activated interface.

About Global and Interface Parameters

To configure Novell IPX as a routing protocol, you must configure both global and interface parameters.

Global Configuration Parameters

Step 1 Start the IPX routing process.

Step 2 Enable load sharing if appropriate for your network.

Load sharing divides routing tasks evenly among multiple routers to balance the work and improve network performance. The switch router supports up to two parallel paths, with a default of one.

Interface Configuration Parameters

Step 1 Assign unique network numbers to each interface.

You can assign multiple network numbers to an interface, allowing support of different encapsulation types. The IPX network number is the number of the Novell network to which the interface is attached. IPX packets received on an interface that does not have a network number are ignored.

Step 2 Set the optional encapsulation type, if it is different from the default.

The default encapsulation type for the switch router is novell-ether (Ethernet_802.3).

Note This section does not describe IPX configuration in detail. Refer to the IPX documentation on the Cisco Documentation CD for detailed conceptual and configuration information.

Configuring Novell IPX Routing

Table 6-5 shows an example of how to enable Novell IPX routing, and configure an interface.

Table 6-5: Configuring Novell IPX Routing

Step Command Description

1
Router(config)# ipx routing [node]

Enables Novell IPX routing, and starts the IPX routing process. If no node address is specified, the switch router uses the MAC address of the interface.

2
Router(config)# ipx maximum-paths number

Allow load sharing over parallel metric paths to the destination. The maximum number of parallel paths is 2; the default number is 1.

3
Router(config)# interface fa x/0/z

Router(config-if)#

Enter Ethernet interface configuration mode to configure the Fast Ethernet interface.

4
Router(config-if)# ipx network number [encapsulation {type}] [secondary]

Each interface must have a unique hexadecimal IPX network number (up to 8 numbers in length).

The encapsulation type is optional. You can specify one of the following types: novell-ether (the default), sap, arpa, or snap.

5
Router(config-if)# Ctrl-Z

Return to privileged EXEC mode.

6
Router# copy running-config startup-config

Save your configuration changes to NVRAM.

Step	Command	Description
1	`Router(config)#` ipx routing `[`node`]`	Enables Novell IPX routing, and starts the IPX routing process. If no node address is specified, the switch router uses the MAC address of the interface.
2	`Router(config)#` ipx maximum-paths number	Allow load sharing over parallel metric paths to the destination. The maximum number of parallel paths is 2; the default number is 1.
3	`Router(config)#` interface fa x/0/z `Router(config-if)#`	Enter Ethernet interface configuration mode to configure the Fast Ethernet interface.
4	`Router(config-if)#` ipx network number `[`encapsulation `{`type`}] [`secondary`]`	Each interface must have a unique hexadecimal IPX network number (up to 8 numbers in length). The encapsulation type is optional. You can specify one of the following types: novell-ether (the default), sap, arpa, or snap.
5	`Router(config-if)#` Ctrl-Z	Return to privileged EXEC mode.
6	`Router#` copy running-config startup-config	Save your configuration changes to NVRAM.

Verifying IPX Operation

The argument number is the number of the Novell network to which that interface is attached. Novell packets received on an interface that does not have a Novell network number are ignored.

Once IPX routing is configured, you can monitor and troubleshoot the protocol operation using the commands in Table 6-6.

Table 6-6: Monitoring and Troubleshooting IPX Operation

Command Displays

show ipx cache

The contents of the IPX fast-switching cache

show ipx interfaces

Status and parameters of the interfaces configured for IPX

show ipx interface fa x/0/z

Status and parameters for the specified Fast Ethernet IPX interface

show ipx route

Contents of the IPX routing table

show ipx servers

The list of IPX servers discovered through SAP advertisements, plus the network address, port number, and the number of hops and ticks to the server

show ipx traffic

Number and type of IPX packets transmitted and received, as well as the number of broadcasts, SAPs, and routing packets received

debug ipx routing activity

Information about RIP update packets

debug ipx sap

Information about SAP update packets

Command	Displays
show ipx cache	The contents of the IPX fast-switching cache
show ipx interfaces	Status and parameters of the interfaces configured for IPX
show ipx interface fa x/0/z	Status and parameters for the specified Fast Ethernet IPX interface
show ipx route	Contents of the IPX routing table
show ipx servers	The list of IPX servers discovered through SAP advertisements, plus the network address, port number, and the number of hops and ticks to the server
show ipx traffic	Number and type of IPX packets transmitted and received, as well as the number of broadcasts, SAPs, and routing packets received
debug ipx routing activity	Information about RIP update packets
debug ipx sap	Information about SAP update packets

Refer to "Comprehensive Configuration Examples," for switch router configuration examples.

About AppleTalk

AppleTalk refers to the Apple network protocol architecture. Layer 3 switching software supports AppleTalk Phase 1 and AppleTalk Phase 2. For AppleTalk Phase 2, Layer 3 switching software support both extended and nonextended networks.

AppleTalk Enhanced IGRP provides automatic redistribution. By default, AppleTalk Routing Table Maintenance Protocol (RTMP) routes are automatically redistributed into Enhanced IGRP, and AppleTalk Enhanced IGRP routes are automatically redistributed into RTMP. If desired, you can turn off redistribution. You can also completely turn off AppleTalk Enhanced IGRP and AppleTalk RTMP either on the device or on its individual interfaces.

Interfaces that are configured for AppleTalk can be configured to use either RTMP, Enhanced IGRP, or both. If two neighboring routers are configured to use both RTMP and Enhanced IGRP, the Enhanced IGRP routing information supersedes the RTMP information, however, both routers continue to send RTMP routing updates. This feature allows you to control the excessive bandwidth usage of RTMP.

Apple Update-based Routing Protocol (AURP) can be enabled on a tunnel interface.

The AppleTalk protocol architecture requires that security measures be implemented at higher application levels. Layer 3 switching supports AppleTalk distribution lists, allowing control of routing updates on a per-interface basis.

To prevent any possible corruption of the AARP table in any AppleTalk node that is performing address gleaning through Media Access Control (MAC), Layer 3 switching AppleTalk does not forward packets with local source and destination network addresses.

Configuring AppleTalk

To enable AppleTalk routing, first enable it on the router, and then configure it on each interface. All routers in a network or data link must agree on the cable range, default zone, and zone list. After an address and a zone name are assigned, the interface is enabled for packet processing.

For more detailed instructions on AppleTalk configuration, see the Cisco IOS Command Reference.

To enable AppleTalk routing, use the procedure in Table 6-7.

Table 6-7: Enabling AppleTalk

Step Command Description

1 .

Router(config)# appletalk routing router_number

Router(config)#

Enable AppleTalk routing in the switch router with the default RTMP routing protocol.

2 .

Router (config)# interface gi x/0/z

Router(config-if)#

From the global configuration mode, enter Ethernet interface configuration mode to configure the Gigabit Ethernet interface.

3 .

Router(config-if)#appletalk cable-range 100-105

Router(config-if)#

Establish a range of six network numbers available to devices on E0. Values can be decimal numbers from 0 to 65279. The starting network number must be less than or equal to the ending network number.

4 .

Router(config-if)#appletalk zone engineering

Router(config-if)#

Place E0 into a zone named engineering. Multiple zone names can be assigned to one interface with AppleTalk 2. The first zone name is the default zone.

5 .

Router(config-if)#Ctrl-Z

Return to privileged EXEC mode.

6 .

Router# copy running-config startup-config

Save your configuration changes to NVRAM.

After you assign the address and zone names, the interface attempts to verify them with another operational router on the connected network. If there are any discrepancies, the interface does not become operational. If there are no neighboring operational routers, the device assumes the interface's configuration is correct, and the interface becomes operational.

Now that you have configured the networking protocols for your switch router, see "Bridging Configurations."

Table of Contents

Networking Protocol Configurations