Tag Switching Commands

This chapter documents commands used to configure Tag Switching features in Cisco IOS software. For guidelines on configuring Tag Switching features, refer to the Cisco IOS Switching Services Configuration Guide.

Note Beginning with Cisco IOS Release 11.3, all commands supported on the Cisco 7500 series routers are also supported on Cisco 7000 series routers.

router traffic-engineering

To configure the traffic engineering routing process, use the router traffic-engineering global configuration command. To turn off the traffic engineering routing process and delete any associated configuration, use the no form of this command.

router traffic-engineering
no router traffic-engineering

Syntax Description

This command has no arguments or keywords.

Defaults

Traffic engineering process is disabled.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

In the following example, configuration is provided for a traffic engineering routing process, a traffic engineering filter, and a traffic engineering route for that filter over a TSP tunnel.

router traffic-engineering
traffic-engineering filter 5 egress 83.0.0.1 255.255.255.255
traffic-engineering route 5 tunnel 5

Related Commands

Command	Description
show ip traffic-engineering	Displays information about the traffic engineering configuration and metric information associated with it.
traffic-engineering filter	Uses the traffic-engineering filter command.
traffic-engineering route	Configures a route for a specified filter, through a specified tunnel.

show ip traffic-engineering

To display information about the traffic engineering configuration and metric information associated with it, use the show ip traffic-engineering privileged EXEC command.

show ip traffic-engineering [metrics [detail]]

Syntax Description

metrics	(Optional) Displays metric information associated with traffic engineering.
detail	(Optional) Displays information in long form.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

The goal of the loop prevention algorithm is that traffic should not be sent down the tunnel if there is a possibility that, after leaving the tunnel, steady state routing will route the traffic back to the head of the tunnel.

The approach of the loop prevention algorithm is to compare the Layer 3 routing distance to the egress from the tunnel tailend and tunnel headend. The loop check passes only if the tunnel tail is closer to the egress than the tunnel head is.

The loop prevention algorithm allows you to use the tunnel for a route if one the following cases applies:

Given that the two ends of the tunnel are routing to the egress using the same dynamic protocol in the same area, the Layer 3 routing distance from the tailend to the egress is less than the Layer 3 routing distance from the headend to the egress.
The route to the egress is directly connected at the tunnel tailend router, but not at the tunnel headend router.
The egress is unreachable from the tunnel headend router, but is reachable from the tunnel tailend router.

The loop prevention algorithm prevents you from using the tunnel for a given egress in all other cases. In particular, when

The routers at the ends of the tunnel get their route to the egress from different dynamic routing protocols.
The routing protocols at the two ends of the tunnel route to the egress through different areas.
The two ends each use a static route to the egress.
The tunnel headend router's route to the egress is a connected route.
The egress is unreachable from the tunnel tailend router.

Devices request metrics via a TDP adjacency. The display output shows detailed metric information.

The metric information includes a metric type (shown as routing_protocol/routing_protocol_subtype) and a metric value.

The routing protocol is as follows:

OSPF
IS-IS
EIGRP
Connected
Static
Other (some other routing protocol)

The routing protocol subtype is specific to each routing protocol.

Examples

The following is sample output from the show ip traffic-engineering metrics detail command:

Router# show ip traffic-engineering metrics detail
 
Metrics requested BY this device
 Prefix 43.0.0.1/32
  TDP id 2.2.2.2:0, metric: connected/0
    type request, flags metric-received, rev 6, refcnt 1
  TDP id 4.4.4.4:0, metric: ospf-300/2
    type request, flags metric-received, rev 7, refcnt 1
 Prefix 44.0.0.0/8
  TDP id 18.18.18.18:0, metric: connected/0
    type request, flags metric-received, rev 1, refcnt 1
Metrics requested FROM this device
 Prefix 36.0.0.0/8
  TDP id 18.18.18.18:0, metric: connected/0
    type advertise, flags none, rev 1, refcnt 1

Table 1 defines the fields displayed in the first three lines of this display.

Table 1: Show IP Traffic-Engineering Metrics Detail Field Descriptions

Field Description

Prefix

Destination network and mask.

TDP id

The TDP identifier of the TDP peer device at the other end of the tunnel. The TDP peer device advertises these metrics to this neighbor.

metric

The routing protocol and metric within that protocol for the prefix in question.

type

For metrics being requested by this device, the type is either request or release. For metrics being requested from this device, the type is advertise.

flags

For metrics being requested by this device metric-received indicates that the other end has responded with a metric value. For metrics being requested from this device, response-pending indicates that the metric value has not yet been sent to the requester.

rev

An internal identifier for the metric request or advertisement. The rev number is assigned when the request/advertisement is created. The rev number is updated if the local information for the metric changes.

refcnt

For a metric of type request, the number of traffic engineering routes interested in this metric value. Otherwise, refcnt is 1.

Related Commands

Command	Description
router traffic-engineering	Configures the traffic engineering routing process.
traffic-engineering filter	Uses the traffic-engineering filter command.
traffic-engineering route	Configures a route for a specified filter, through a specified tunnel.

show ip traffic-engineering configuration

To display information about configured traffic engineering filters and routes, use the show ip traffic-engineering configuration privileged EXEC command.

show ip traffic-engineering configuration [interface] [filter-number] [detail]

Syntax Description

interface	(Optional) Specifies an interface for which to display traffic engineering information.
filter-number	(Optional) A decimal value representing the number of the filter to display.
detail	(Optional) Displays command output in long form.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

The sample output can show all filters or can be limited by interface, filter number, or both.

Examples

The following is sample output from the show ip traffic-engineering configuration detail command:

Router# show ip traffic-engineering configuration detail
 
Traffic Engineering Configuration
    Filter 5: egress 44.0.0.0/8, local metric: ospf-0/1
        Tunnel5 route installed
          interface up, preference 1
          loop check on, passing, remote metric: connected/0
    Filter 6: egress 43.0.0.1/32, local metric: ospf-300/3
        Tunnel7 route installed
          interface up, preference 50
          loop check on, passing, remote metric: ospf-300/2
        Tunnel6 route not installed
          interface up, preference 75
          loop check on, passing, remote metric: connected/0

Table 2 describes the fields displayed in the first four lines of this display.

Table 2: Show IP Traffic-Engineering Configuration Detail Field Descriptions

Field Description

Filter

The configured filter identifier for the traffic engineering route.

egress

The prefix/mask configured with the filter local metric.

local metric

The local TSR's routing protocol and metric value for the egress prefix/mask.

Tunnel5

The tunnel for the traffic engineering route.

route installed/not installed

Indicates whether the route is installed in the forwarding tables (typically CEF and tag interface up/down).

interface

Indicates whether the tunnel interface for the traffic engineering route is up or down. The traffic engineering route is not installed if the tunnel interface is down.

preference

The configured administrative preference for the traffic engineering route.

loop check

Indicates whether the loop check has been configured on or off.

passing/failing

If the loop check is configured on, indicates whether the check is passing. The traffic engineering route is not installed if the loop check is configured on and is failing.

remote metric

The routing protocol and the metric within that protocol for the prefix in question, as seen by the TSR advertising the metric. As part of the loop check, a comparison is made between the remote metric and the local metric.

Field	Description
Filter	The configured filter identifier for the traffic engineering route.
egress	The prefix/mask configured with the filter local metric.
local metric	The local TSR's routing protocol and metric value for the egress prefix/mask.
Tunnel5	The tunnel for the traffic engineering route.
route installed/not installed	Indicates whether the route is installed in the forwarding tables (typically CEF and tag interface up/down).
interface	Indicates whether the tunnel interface for the traffic engineering route is up or down. The traffic engineering route is not installed if the tunnel interface is down.
preference	The configured administrative preference for the traffic engineering route.
loop check	Indicates whether the loop check has been configured on or off.
passing/failing	If the loop check is configured on, indicates whether the check is passing. The traffic engineering route is not installed if the loop check is configured on and is failing.
remote metric	The routing protocol and the metric within that protocol for the prefix in question, as seen by the TSR advertising the metric. As part of the loop check, a comparison is made between the remote metric and the local metric.

Related Commands

Command	Description
show ip traffic-engineering routes	Displays information about the requested filters configured for traffic engineering.

show ip traffic-engineering routes

To display information about the requested filters configured for traffic engineering, use the show ip traffic-engineering routes privileged EXEC command.

show ip traffic-engineering routes [filter-number] [detail]

Syntax Description

filter-number	(Optional) A decimal value representing the number of the filter to display.
detail	(Optional) Display of command output in long form.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

Requests can be limited to a specific filter.

Examples

The following is sample output from the show ip traffic-engineering routes command:

Router# show ip traffic-engineering routes
 
Installed traffic engineering routes:
Codes: T - traffic engineered route
T    43.0.0.1/32 (not override of routing table entry)
                is directly connected, 00:06:35, Tunnel7
T    44.0.0.0/8 (override of routing table entry)
               is directly connected, 01:12:39, Tunnel5

Table 3 describes the significant fields in this display.

Table 3: Show IP Traffic-Engineering Routes Field Descriptions

Field Description

T

Traffic engineering route.

43.0.0.1/32 (not override of routing table entry) is directly connected

Prefix/mask being routed. The routing table does not contain an entry for this prefix/mask.

00:06:35

The time since the route was installed (hours:minutes:seconds).

Tunnel7

The TSP tunnel for the route.

Field	Description
T	Traffic engineering route.
43.0.0.1/32 (not override of routing table entry) is directly connected	Prefix/mask being routed. The routing table does not contain an entry for this prefix/mask.
00:06:35	The time since the route was installed (hours:minutes:seconds).
Tunnel7	The TSP tunnel for the route.

Related Commands

Command	Description
show ip traffic-engineering configuration	Displays information about configured traffic engineering filters and routes.

show tag-switching atm-tdp bindings

To display the requested entries from the ATM TDP tag binding database, use the show tag-switching atm-tdp bindings privileged EXEC command. The ATM TDP database contains TIB entries for tag VCs on TC-ATM interfaces.

show tag-switching atm-tdp bindings [network {mask | length}] [local-tag vpi vci ][remote-tag vpi vci] [neighbor interface]

Syntax Description

network	(Optional) Destination network number.
mask	Network mask in the form A.B.C.D (destination prefix).
length	Mask length (1 to 32).
local-tag vpi vci	(Optional) Select tag VC value assigned by this router.
remote-tag vpi vci	(Optional) Select tag values assigned by the other router.
neighbor interface	(Optional) Select tag values assigned by neighbor on a specified interface.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

The display output can show entries from the entire database, or it can be limited to a subset of entries based on prefix, VC tag value, and/or an assigning interface.

Examples

The following is router sample output from the show tag-switching atm-tdp bindings command:

Router# show tag-switching atm-tdp bindings
 
Destination: 10.16.0.16/32
    Tailend Router ATM1/0.1 1/35 1/34 Active, VCD=2
Destination: 10.24.0.0/24
    Tailend Router ATM1/0.1 1/39 Active, VCD=3
Destination: 10.15.0.15/32
    Tailend Router ATM1/01 1/33 Active, VCD=4
Destination: 10.23.0 0/24
    Tailend Router ATM1/01 1/37 Active, VCD=5

Table 4 describes the significant fields in this display.

Table 4: Show Tag-Switching ATM-TDP Bindings Field Descriptions

Field Description

Destination:

Destination (network/mask)

Tailend Router

Types of VC. Options are

Tailend---VC that terminates at this router

Headend---VC that originates at this router

Transit---VC that passes through a switch

ATM1/0.1

Interface.

1/35

VPI/VCI.

Active

TVC state:

Active---Set up and working.

Bindwait---Waiting for response.

Remote Resource Wait---Waiting for resources (VPI/VCI space) to be available on the downstream device.

Parent Wait---Transit VC input side waiting for output side to become active.

VCD=2

Virtual circuit descriptor number.

The following is ATM switch sample output from the show tag-switching atm-tdp bindings command:

Switch# show tag-switching atm-tdp bindings
 
Destination: 6.6.6.6/32
    Tailend Switch ATM0/0/3 1/34 Active -> Terminating Active
 Destination: 150.0.0.0/16
    Tailend Switch ATM0/0/3 1/35 Active -> Terminating Active
 Destination: 4.4.4.4/32
    Transit ATM0/0/3 1/33 Active -> ATM0/1/1 1/33 Active

Related Commands

Command	Description
show tag-switching atm-tdp summary	Displays summary information on ATM tag bindings.

show tag-switching atm-tdp capability

To display the ATM TDP tag capabilities, use the show tag-switching atm-tdp capability privileged EXEC command.

show tag-switching atm-tdp capability

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

The following example shows the display from the show tag-switching atm-tdp capability command.

Router# show tag-switching atm-tdp capability
 
VPI           VCI           Alloc   Odd/Even  VC Merge 
ATM0/1/0       Range         Range         Scheme  Scheme    IN   OUT  
  Negotiated   [100 - 101]   [33 - 1023]   UNIDIR            -    -    
  Local        [100 - 101]   [33 - 16383]  UNIDIR            EN   EN   
  Peer         [100 - 101]   [33 - 1023]   UNIDIR            -    -    
 
               VPI           VCI           Alloc   Odd/Even  VC Merge     
ATM0/1/1       Range         Range         Scheme  Scheme    IN   OUT  
  Negotiated   [201 - 202]   [33 - 1023]   BIDIR             -    -    
  Local        [201 - 202]   [33 - 16383]  UNIDIR  ODD       NO   NO   
  Peer         [201 - 202]   [33 - 1023]   BIDIR   EVEN      -    -

Table 5 lists the significant fields in this display.

Table 5: Show Tag-Switching ATM-TDP Capability Field Descriptions

Field Description

VPI Range

Minimum and maximum number of VPIs supported on this interface.

VCI Range

Minimum and maximum number of VCIs supported on this interface.

Alloc Scheme

UNIDIR---Unidirectional capability indicates that the peer device can, within a single VPI, support binding of the same VCI to different prefixes on different directions of the link.

BIDIR---Bidirectional capability indicates that within a single VPI, a single VCI can appear in one binding only. In this case, one peer device allocates bindings in the even VCI space, and the other in the odd VCI space. The system with the lower TDP identifier will assign even-numbered VCIs.

The negotiated allocation scheme is UNIDIR, if and only if, both peer devices have UNIDIR capability. Otherwise it is BIDIR.

Odd/Even Scheme

Indicates whether the local device or the peer device is assigning an odd- or even-numbered VCI when the negotiated scheme is BIDIR. It does not display any information when the negotiated scheme is UNIDIR.

VC Merge

Indicates the type of VC merge support on this interface.

IN---Indicates input interface merge capability. IN accepts the following values:

EN---The hardware interface supports VC merge and VC merge is enabled on the device.

DIS---The hardware interface supports VC merge and VC merge is disabled on the device.

NO---The hardware interface does not support VC merge.

OUT---Indicates output interface merge capability. OUT accepts the same values as the input merge side.

The VC merge capability is meaningful only on ATM switches. It is not negotiated.

Negotiated

Set of options that both TDP peer devices have agreed to share on this interface. For example, the VPI or VCI allocation on either peer device remains within the negotiated ranges.

Local

Options supported locally on this interface.

Peer

Options supported by the remote TDP peer device on this interface.

Field	Description
VPI Range	Minimum and maximum number of VPIs supported on this interface.
VCI Range	Minimum and maximum number of VCIs supported on this interface.
Alloc Scheme	UNIDIR---Unidirectional capability indicates that the peer device can, within a single VPI, support binding of the same VCI to different prefixes on different directions of the link. BIDIR---Bidirectional capability indicates that within a single VPI, a single VCI can appear in one binding only. In this case, one peer device allocates bindings in the even VCI space, and the other in the odd VCI space. The system with the lower TDP identifier will assign even-numbered VCIs. The negotiated allocation scheme is UNIDIR, if and only if, both peer devices have UNIDIR capability. Otherwise it is BIDIR.
Odd/Even Scheme	Indicates whether the local device or the peer device is assigning an odd- or even-numbered VCI when the negotiated scheme is BIDIR. It does not display any information when the negotiated scheme is UNIDIR.
VC Merge	Indicates the type of VC merge support on this interface. IN---Indicates input interface merge capability. IN accepts the following values: EN---The hardware interface supports VC merge and VC merge is enabled on the device. DIS---The hardware interface supports VC merge and VC merge is disabled on the device. NO---The hardware interface does not support VC merge. OUT---Indicates output interface merge capability. OUT accepts the same values as the input merge side. The VC merge capability is meaningful only on ATM switches. It is not negotiated.
Negotiated	Set of options that both TDP peer devices have agreed to share on this interface. For example, the VPI or VCI allocation on either peer device remains within the negotiated ranges.
Local	Options supported locally on this interface.
Peer	Options supported by the remote TDP peer device on this interface.

Related Commands

Command	Description
tag-switching atm control-vc	Configures the VPI and VCI to be used for the initial link to the Tag Switching peer device.
tag-switching atm vc-merge	Controls whether vc-merge (multipoint-to-point) is supported for unicast tag VCs.
tag-switching atm vpi	Configures the range of values to use in the VPI field for tag VCs.

show tag-switching atm-tdp summary

To display summary information on ATM tag bindings, use the show tag-switching atm-tdp summary privileged EXEC command.

show tag-switching atm-tdp summary

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

The following is sample output from the show tag-switching atm-tdp summary command:

Router# show tag-switching atm-tdp summary
 
Total number of destinations: 788

TC-ATM bindings summary
interface   total     active    bindwait  local     remote    other
ATM0/0/0    594       592       1         296       298       1
ATM0/0/1    590       589       0         294       296       1
ATM0/0/2    1179      1178      0         591       588       1
ATM0/0/3    1177      1176      0         592       585       1
ATM0/1/0    1182      1178      4         590       588       0
Waiting for bind on ATM0/0/0 10.21.0.0/24

Table 6 describes the significant fields in this display.

Table 6: Show Tag-Switching ATM-TDP Summary Field Descriptions

Field Description

Total number of destinations

The number of known destination address prefixes.

interface

The name of an interface with associated ATM tag bindings.

total

The total number of ATM tags on this interface.

active

The number of ATM tags in an "active" state that are ready to use for data transfer.

bindwait

The number of bindings that are waiting for a tag assignment from the neighbor TSR.

local

The number of ATM tags assigned by this TSR on this interface.

remote

The number of ATM tags assigned by the neighbor TSR on this interface.

other

The number of ATM tags in a state other than "active" or "bindwait."

Waiting for bind on ATM0/0/0

A list of the destination address prefixes (on a particular interface) that are waiting for ATM tag assignment from the neighbor TSR.

Field	Description
Total number of destinations	The number of known destination address prefixes.
interface	The name of an interface with associated ATM tag bindings.
total	The total number of ATM tags on this interface.
active	The number of ATM tags in an "active" state that are ready to use for data transfer.
bindwait	The number of bindings that are waiting for a tag assignment from the neighbor TSR.
local	The number of ATM tags assigned by this TSR on this interface.
remote	The number of ATM tags assigned by the neighbor TSR on this interface.
other	The number of ATM tags in a state other than "active" or "bindwait."
Waiting for bind on ATM0/0/0	A list of the destination address prefixes (on a particular interface) that are waiting for ATM tag assignment from the neighbor TSR.

Related Commands

Command	Description
show tag-switching atm-tdp bindings	Displays the requested entries from the ATM TDP tag binding database.

show tag-switching forwarding-table

To display the contents of the Tag Forwarding Information Base (TFIB), use the show tag-switching forwarding-table privileged EXEC command.

show tag-switching forwarding-table [{network {mask | length} | tags tag [- tag] | interface interface | next-hop address | tsp-tunnel [tunnel-id ]}] [detail]

Syntax Description

network	(Optional) Destination network number.
mask	IP address of destination mask whose entry is to be shown.
length	Number of bits in mask of destination.
tags tag - tag	(Optional) Shows entries with specified local tags only.
interface interface	(Optional) Shows entries with specified outgoing interface only.
next-hop address	(Optional) Shows entries with specified neighbor as next hop only.
tsp-tunnel [tunnel-id]	(Optional) Shows entries with specified TSP tunnel only, or all TSP tunnel entries.
detail	(Optional) Displays information in long form (includes length of encapsulation, length of MAC string, maximum transmission unit (MTU), and all tags).

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

The optional parameters allow specification of a subset of the entire TFIB.

Examples

The following is sample output from the show tag-switching forwarding-table command:

Router# show tag-switching forwarding-table
 
Local Outgoing      Prefix            Bytes tag Outgoing       Next Hop       
tag   tag or VC     or Tunnel Id      switched  interface                     
26    Untagged      10.253.0.0/16     0         Et4/0/0       172.27.32.4    
28    1/33          10.15.0.0/16      0         AT0/0.1       point2point    
29    Pop tag       10.91.0.0/16      0         Hs5/0         point2point    
      1/36          10.91.0.0/16      0         AT0/0.1       point2point    
30    32            10.250.0.97/32    0         Et4/0/2       10.92.0.7      
      32            10.250.0.97/32    0         Hs5/0         point2point    
34    26            10.77.0.0/24      0         Et4/0/2       10.92.0.7      
      26            10.77.0.0/24      0         Hs5/0         point2point    
35    Untagged  [T] 10.100.100.101/32 0         Tu301         point2point    
36    Pop tag       168.1.0.0/16      0         Hs5/0         point2point    
      1/37          168.1.0.0/16      0         AT0/0.1       point2point    
 
[T]     Forwarding through a TSP tunnel.
        View additional tagging info with the 'detail' option

The following is sample output from the show tag-switching forwarding-table command when you specify detail:

Router# show tag-switching forwarding-table detail
 
Local Outgoing      Prefix            Bytes tag Outgoing       NextHop       
tag   tag or VC     or Tunnel Id      switched  interface                     
26    Untagged      10.253.0.0/16     0         Et4/0/0       172.27.32.4    
        MAC/Encaps=0/0, MTU=1504, Tag Stack{}
28    1/33          10.15.0.0/16      0         AT0/0.1       point2point    
        MAC/Encaps=4/8, MTU=4470, Tag Stack{1/33(vcd=2)}
        00020900 00002000
29    Pop tag       10.91.0.0/16      0         Hs5/0         point2point    
        MAC/Encaps=4/4, MTU=4474, Tag Stack{}
        FF030081 
      1/36          10.91.0.0/16      0         AT0/0.1       point2point    
        MAC/Encaps=4/8, MTU=4470, Tag Stack{1/36(vcd=3)}
        00030900 00003000
30    32            10.250.0.97/32    0         Et4/0/2       10.92.0.7      
        MAC/Encaps=14/18, MTU=1500, Tag Stack{32}
        006009859F2A00E0F7E984828847 00020000
      32            10.250.0.97/32    0         Hs5/0         point2point    
        MAC/Encaps=4/8, MTU=4470, Tag Stack{32}
        FF030081 00020000
34    26            10.77.0.0/24      0         Et4/0/2       10.92.0.7      
        MAC/Encaps=14/18, MTU=1500, Tag Stack{26}
        006009859F2A00E0F7E984828847 0001A000
      26            10.77.0.0/24      0         Hs5/0         point2point    
        MAC/Encaps=4/8, MTU=4470, Tag Stack{26}
        FF030081 0001A000
35    Untagged      10.100.100.101/32 0         Tu301         point2point    
        MAC/Encaps=0/0, MTU=1504, Tag Stack{}, via Et4/0/2
36    Pop tag       168.1.0.0/16      0         Hs5/0         point2point    
        MAC/Encaps=4/4, MTU=4474, Tag Stack{}
        FF030081 
      1/37          168.1.0.0/16      0         AT0/0.1       point2point    
        MAC/Encaps=4/8, MTU=4470, Tag Stack{1/37(vcd=4)}
        00040900 00004000

Table 7 describes the significant fields in this display.

Table 7: Show Tag-Switching Forwarding-Table Field Descriptions

Field Description

Local tag

Tag assigned by this router.

Outgoing tag or VC

Tag assigned by next hop, or VPI/VCI used to get to next hop. Some of the entries you can have in this column are

[T] means forwarding through a TSP tunnel.

"Untagged" means there is no tag for the destination from the next hop, or Tag Switching is not enabled on the outgoing interface.

"Pop tag" means the next hop advertised an implicit NULL tag for the destination, and this router popped the top tag.

Prefix or Tunnel Id

Address or tunnel to which packets with this tag are going.

Bytes tag switched

Number of bytes switched with this incoming tag.

Outgoing interface

Interface through which packets with this tag are sent.

NextHop

IP address of neighbor that assigned the outgoing tag.

Mac/Encaps

Length in bytes of Layer 2 header, and length in bytes of packet encapsulation, including Layer 2 header and tag header.

MTU

Maximum transmission unit (MTU) of tagged packet.

Tag Stack

All the outgoing tags. If the outgoing interface is TC-ATM, the VCD is also shown.

00020900 00002000

The actual encapsulation in hexadecimal form. There is a space shown between Layer 2 and tag header.

show tag-switching interfaces

To display information about one or more interfaces that have Tag Switching enabled, use the show tag-switching interfaces privileged EXEC command.

show tag-switching interfaces [interface][detail]

Syntax Description

interface	(Optional) The interface about which to display Tag Switching information.
detail	(Optional) Displays information in long form.

Command Modes

EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

You can show information about the requested interface or about all interfaces on which Tag Switching is enabled.

Examples

The following is sample output from the show tag-switching interfaces command:

Router# show tag-switching interfaces
 
Interface              IP    Tunnel   Operational
Hssi3/0                Yes   Yes      No          
ATM4/0.1               Yes   Yes      Yes         (ATM tagging)
Ethernet5/0/0          No    Yes      Yes         
Ethernet5/0/1          Yes   No       Yes         
Ethernet5/0/2          Yes   No       No          
Ethernet5/0/3          Yes   No       Yes         
Ethernet5/1/1          Yes   No       No

Note If the interface uses TC-ATM procedures, the line in the display output is marked (ATM tagging).

Table 8 describes the significant fields in this display.

Table 8: Show Tag-Switching Interfaces Command Field Descriptions

Field Description

Interface

Interface name.

IP

"Yes" if IP tagging has been enabled on this interface.

Tunnel

"Yes" if TSP tunnel tagging has been enabled on this interface.

Operational

Operational state. "Yes" if packets are being tagged.

MTU

Maximum number of data bytes per tagged packet that will be transmitted.

The following is sample output from the show tag-switching interfaces command when you specify detail:

Router# show tag-switching interface Ethernet2/0/1 detail
 
Interface Hssi3/0:
        IP tagging enabled
        TSP Tunnel tagging enabled
        Tagging not operational
        MTU = 4470
Interface ATM4/0.1:
        IP tagging enabled
        TSP Tunnel tagging enabled
        Tagging operational
        MTU = 4470
        ATM tagging: Tag VPI = 1, Control VC = 0/32
Interface Ethernet5/0/0:
        IP tagging not enabled
        TSP Tunnel tagging enabled
        Tagging operational
        MTU = 1500
Interface Ethernet5/0/1:
        IP tagging enabled
        TSP Tunnel tagging not enabled
        Tagging operational
        MTU = 1500
Interface Ethernet5/0/2:
        IP tagging enabled
        TSP Tunnel tagging not enabled
        Tagging not operational
        MTU = 1500
Interface Ethernet5/0/3:
        IP tagging enabled
        TSP Tunnel tagging not enabled
        Tagging operational
        MTU = 1500

Related Commands

Command	Description
tag-switching ip (interface configuration)	Enables Tag Switching of IPv4 packets on an interface.
tag-switching tsp-tunnels (interface configuration)	Allows TSP tunnel operation over an interface.

show tag-switching tdp bindings

To display the contents of the tag information base (TIB), use the show tag-switching tdp bindings privileged EXEC command:

show tag-switching tdp bindings [network {mask | length} [longer-prefixes]] [local-tag tag [- tag]} [remote-tag tag [- tag] [neighbor address] [local]

Syntax Description

network	(Optional) Destination network number.
mask	Network mask written as A.B.C.D.
length	Mask length (1 to 32 characters).
longer-prefixes	(Optional) Selects any prefix that matches mask with length to 32.
local-tag tag - tag	(Optional) Display entries matching local tag values by this router. Use the - tag argument to indicate tag range.
remote-tag tag - tag	(Optional) Displays entries matching tag values assigned by a neighbor router. Use the - tag argument to indicate tag range.
neighbor address	(Optional) Displays tag bindings assigned by selected neighbor.
local	(Optional) Displays local tag bindings.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

A request can specify that the entire database be shown, or it or can be limited to a subset of entries. A request to show a subset of entries can be based on the prefix, on input or output tag values or on ranges, and/or the neighbor advertising the tag.

Examples

The following is sample output from the show tag-switching tdp bindings command. This form of the command causes the contents of the entire TIB to be displayed.

Router# show tag-switching tdp bindings
 
Matching entries:
  tib entry: 10.92.0.0/16, rev 28
        local binding:  tag: imp-null(1)
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 10.102.0.0/16, rev 29
        local binding:  tag: 26
        remote binding: tsr: 172.27.32.29:0, tag: 26
  tib entry: 10.105.0.0/16, rev 30
        local binding:  tag: imp-null(1)
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 10.205.0.0/16, rev 31
        local binding:  tag: imp-null(1)
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 10.211.0.7/32, rev 32
        local binding:  tag: 27
        remote binding: tsr: 172.27.32.29:0, tag: 28
  tib entry: 10.220.0.7/32, rev 33
        local binding:  tag: 28
        remote binding: tsr: 172.27.32.29:0, tag: 29
  tib entry: 99.101.0.0/16, rev 35
        local binding:  tag: imp-null(1)
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 100.101.0.0/16, rev 36
        local binding:  tag: 29
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 171.69.204.0/24, rev 37
        local binding:  tag: imp-null(1)
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 172.27.32.0/22, rev 38
        local binding:  tag: imp-null(1)
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 210.10.0.0/16, rev 39
        local binding:  tag: imp-null(1)
  tib entry: 210.10.0.8/32, rev 40
        remote binding: tsr: 172.27.32.29:0, tag: 27

The following is sample output from the show tag tdp bindings 10.0.0.0 8 longer-prefixes neighbor 172.27.32.29 variant of the command; it displays tags learned from TSR 172.27.32.29 for network 10.0.0.0 and any of its subnets. The use of the neighbor option suppresses the output of local tags and tags learned from other neighbors.

Router# show tag tdp bindings 10.0.0.0 8 longer-prefixes neighbor 172.27.32.29
 
  tib entry: 10.92.0.0/16, rev 28
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 10.102.0.0/16, rev 29
        remote binding: tsr: 172.27.32.29:0, tag: 26
  tib entry: 10.105.0.0/16, rev 30
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 10.205.0.0/16, rev 31
        remote binding: tsr: 172.27.32.29:0, tag: imp-null(1)
  tib entry: 10.211.0.7/32, rev 32
        remote binding: tsr: 172.27.32.29:0, tag: 28
  tib entry: 10.220.0.7/32, rev 33
        remote binding: tsr: 172.27.32.29:0, tag: 29

Table 9 describes the significant fields in this display.

Table 9: Show Tag-Switching TDP Bindings Field Descriptions

Field Description

tib entry

Indicates that the following lines are the TIB entry for a particular destination (network/mask). The revision number is used internally to manage tag distribution for this destination.

remote binding

A list of outgoing tags for this destination learned from other Tag Switching Routers (TSRs). Each item on this list identifies the TSR from which the outgoing tag was learned and the tag itself. The TSR is identified by its TDP identifier.

imp-null

The implicit null tag. This tag value instructs the upstream router to pop the tag entry off the tag stack before forwarding the packet.

Related Commands

Command	Description
show tag-switching forwarding-table	Displays the contents of the TFIB.
show tag-switching tdp neighbors	Displays the status of TDP sessions.

show tag-switching tdp discovery

To display the status of the TDP discovery process, use the show tag-switching tdp discovery privileged EXEC command. Status means a list of interfaces over which TDP discovery is running.

show tag-switching tdp discovery

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

The following is sample output from the show tag-switching tdp discovery command.

Router# show tag-switching tdp discovery
 
Local TDP Identifier:
    172.27.32.29:0
TDP Discovery Sources:
    Interfaces:
ATM0/0.1:       xmit/recv
ATM0/0.1:       xmit/rec
Ethernet4/0/1:  xmit/recv
Ethernet4/0/2:  xmit/recv
POS6/0/0:       xmit/recv

Table 10 describes the significant fields in this display.

Table 10: Show Tag-Switching TDP Discovery Field Descriptions

Field Description

Local TDP Identifier

The TDP identifier for the local router. A TDP identifier is a 6-byte quantity displayed as an IP address:number.

The Cisco convention is to use a router ID for the first 4 bytes of the TDP identifier, and integers starting with 0 for the final two bytes of the IP address:number.

Interfaces

Lists the interfaces engaging in TDP discovery activity. xmit indicates that the interface is transmitting TDP discovery hello packets; recv indicates that the interface is receiving TDP discovery hello packets.

Related Commands

Command	Description
show tag-switching tdp neighbors	Displays the status of TDP sessions.

show tag-switching tdp neighbors

To display the status of Tag Distribution Protocol (TDP) sessions, enter the show tag-switching tdp neighbor privileged EXEC command:

show tag-switching tdp neighbors [address | interface] [detail]

Syntax Description

address	(Optional) The neighbor with this IP address.
interface	(Optional) TDP neighbors accessible over this interface.
detail	(Optional) Displays information in long form.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

The neighbor information branch can give information about all TDP neighbors, or it can be limited to

The neighbor with a specific IP address
TDP neighbors known to be accessible over a specific interface

Examples

The following is sample output from the show tag-switching tdp neighbors command:

Router# show tag-switching tdp neighbors
 
Peer TDP Ident: 10.220.0.7:1; Local TDP Ident 172.27.32.29:1
        TCP connection: 10.220.0.7.711 - 172.27.32.29.11029
        State: Oper; PIEs sent/rcvd: 17477/17487; Downstream on demand
Up time: 01:03:00
TDP discovery sources:
          ATM0/0.1
Peer TDP Ident: 210.10.0.8:0; Local TDP Ident 172.27.32.29:0
        TCP connection: 210.10.0.8.11004 - 172.27.32.29.711
        State: Oper; PIEs sent/rcvd: 14656/14675; Downstream
Up time: 2d5h
        TDP discovery sources:
          Ethernet4/0/1
          Ethernet4/0/2
          POS6/0/0
        Addresses bound to peer TDP Ident:
          99.101.0.8      172.27.32.28    10.105.0.8      10.92.0.8       
          10.205.0.8      210.10.0.8

Table 11 describes the significant fields in this display.

Table 11: Show Tag-Switching TDP Neighbors Field Descriptions

Field Description

Peer TDP Ident

The TDP identifier of the neighbor (peer device) for this session.

Local TDP Ident

The TDP identifier for the local TSR for this session.

TCP connection

The TCP connection used to support the TDP session. The format for displaying the TCP connection is

peer IP address.peer port
local IP address.local port

State

The state of the TDP session. Generally this is Oper (operational), but transient is another possible state.

PIEs sent/rcvd

The number of TDP protocol information elements (PIEs) sent to and received from the session peer device. The count includes the transmission and receipt of periodic keep alive PIEs, which are required for maintenance of the TDP session.

Downstream

Indicates that the downstream method of tag distribution is being used for this TDP session. When the downstream method is used, a TSR advertises all of its locally assigned (incoming) tags to its TDP peer device (subject to any configured access list restrictions).

Downstream on demand

Indicates that the downstream on demand method of tag distribution is being used for this TDP session. When the downstream on demand method is used, a TSR advertises its locally assigned (incoming) tags to its TDP peer device only when the peer device asks for them.

Up time

The length of time the TDP session has existed.

TDP discovery sources

The source(s) of TDP discovery activity that led to the establishment of this TDP session.

Addresses bound to peer TDP Ident

The known interface addresses of the TDP session peer device. These are addresses that may appear as "next hop" addresses in the local routing table. They are used to maintain the Tag Forwarding Information Base (TFIB).

Related Commands

Command	Description
show tag-switching tdp discovery	Displays the status of the TDP discovery process.

show tag-switching tdp parameters

To display available TDP parameters, use the show tag-switching tdp parameters privileged EXEC command:

show tag-switching tdp parameters

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

The following is sample output from the show tag-switching tdp parameters command:

Router# show tag-switching tdp parameters
 
Protocol version: 1
 Downstream tag pool: min tag: 10; max_tag: 10000; reserved tags: 16
 Session hold time: 15 sec; keep alive interval: 5 sec
 Discovery hello: holdtime: 15 sec; interval: 5 sec
 Discovery directed hello: holdtime: 15 sec; interval: 5 sec
 Accepting directed hellos

Table 12 describes the significant fields in this display.

Table 12: Show Tag-Switching TDP Parameters Command Field Descriptions

Field Description

Protocol version

Indicates the version of the Tag Distribution Protocol (TDP) running on the platform.

Downstream tag pool

Describes the range of tags available for the platform to assign for Tag Switching. The tags available run from the smallest tag value (min tag) to the largest tag value (max tag), with a modest number of tags at the low end of the range (reserved tags) reserved for diagnostic purposes.

Session hold time

Indicates the time to maintain a TDP session with a TDP peer device without receiving TDP traffic or a TDP keep alive from the peer device.

keep alive interval

Indicates the interval of time between consecutive transmission TDP keep alive messages to a TDP peer device.

Discovery hello

Indicates the amount of time to remember that a neighbor platform wants a TDP session without receiving a TDP Hello from the neighbor (holdtime), and the time interval between transmitting TDP Hello messages to neighbors (interval).

Discovery directed hello

Indicates the amount of time to remember that a neighbor platform wants a TDP session when (1) the neighbor platform is not directly connected to the router and (2) the neighbor platform has not sent a TDP Hello message. The interval is known as holdtime.

Also indicates the time interval between the transmission of Hello messages to a neighbor not directly connected to the router.

Accepting directed hellos

Indicates that the platform will accept and act on Directed TDP Hello messages (may not be present).

Related Commands

Command	Description
tag-switching tdp discovery	Configures the interval between transmission of TDP discovery hello messages.
tag-switching tdp holdtime	Enables TSP tunnel functionality on a device.

show tag-switching tsp-tunnels

To display information about the configuration and status of selected tunnels, use the show tag-switching tsp-tunnels privileged EXEC command.

show tag-switching tsp-tunnels [{head | middle | tail | all | remote | address}
[interface-number]] [brief]

Syntax Description

head	(Optional) Displays information for tunnels that originate at the node.
middle	(Optional) Displays information for tunnels that pass through the node.
tail	(Optional) Displays information for tunnels that terminate at the node.
all	(Optional) Displays the combination of head, middle, and tail information for tunnels.
remote	(Optional) Displays information for tunnels that originate elsewhere; it is thus is the combination of middle and tail.
address	(Optional) Displays information for tunnels that use the specified address in their identifier.
interface-number	(Optional) Displays information for tunnels that use the specified number in their identifier.
brief	(Optional) Displays a brief summary of tunnel status and configuration.

Command Modes

Privileged EXEC

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

The optional keywords restrict the set of tunnels displayed. With no optional keywords, the command displays all tunnels passing through the node.

Each TSP tunnel has a globally unique identifier. When signalling the TSP tunnel is signalled and is available at each hop, this identifier is used. This identifier is a combination of the originating IP address and the number of the Cisco IOS tunnel interface used in configuring the TSP tunnel at the headend.

Examples

The following is sample output from the show tag-switching tsp-tunnels command:

Signalling Summary:
            TSP Tunnels Process:            running
            RSVP Process:                   running
            Forwarding:                     enabled
TUNNEL ID               DESTINATION      STATUS           CONNECTION
10.106.0.6 0            10.2.0.12        up               up

Table 13 describes the significant fields in this display.

Table 13: Show Tag-Switching TSP-Tunnels Field Descriptions

Field Description

Signalling Summary

The status of the signalling and forwarding mechanism that is required in order for TSP tunnels to be signalled through the router.

TSP Tunnels Process

The status of the TSP tunnel signalling process. This process interacts with the signalling protocol to manage signalled tunnels and monitors the state of established tunnels.

RSVP Process

The status of the RSVP process. You use the RSVP protocol to signal tunnels.

Forwarding

The status of the forwarding mechanism used to switch data through local TSP tunnel segments.

TUNNEL ID

The identity of the tunnel being summarized as shown in the previous display output. The tunnel ID includes an IP address part and a number part, and is unique within the entire network.

DESTINATION

The destination of the TSP tunnel being summarized as shown in the previous display output---the IP address of the tunnel tail.

STATUS

The configuration status of the tunnel. At the head, this is an indication whether or not the tunnel has been completely configured. It also refers to the status of the associated software and hardware interfaces.

CONNECTION

The connection status of the tunnel. This is an indication whether or not the local signalling/configuration information shows that the tunnel is up. Typically the tunnel becomes "up" at the tail hop first, and then at the second to the last hop, and so forth until signalling brings it up at the first hop.

Related Commands

Command	Description
tag-switching tsp-tunnels (interface configuration)	Allows TSP tunnel operation over an interface.
tunnel mode tag-switching	Sets the encapsulation mode of the tunnel to Tag Switching.

tag-switching advertise-tags

To control the distribution of locally assigned (incoming) tags via the Tag Distribution Protocol (TDP), use the tag-switching advertise-tags global configuration command. To disable tag advertisement, use the no form of this command.

tag-switching advertise-tags [for access-list-number [to access-list-number]
no tag-switching advertise-tags [for access-list-number [to access-list-number]

Syntax Description

for access-list-number

(Optional) Specifies which destinations should have their tags advertised.

to access-list-number

(Optional) Specifies which TSR neighbors should receive tag advertisements.

A TSR is identified by the router ID that is the first 4 bytes of its 6-byte TDP identifier.

Defaults

Advertise all to all is the default.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

To enable the distribution of all locally assigned tags to all TDP neighbors, use the tag-switching advertise-tags command

You can enter multiple tag-switching advertise-tags commands. Taken together, they determine how local tags are advertised.

Note This command has no effect for a TC-ATM interface. The effect is always as if the tag-switching advertise-tags command had been executed.

Examples

In the following example, the router is configured to advertise all locally assigned tags to all TDP neighbors. This is the default.

Router(config)# tag-switching advertise-tags

In the following example, the router is configured to advertise to all TDP neighbors tags for networks 10.101.0.0 and 10.221.0.0 only.

Router(config)# access-list 1 permit 10.101.0.0 0.0.255.255
Router(config)# access-list 4 permit 10.221.0.0 0.0.255.255
Router(config)# tag-switching advertise-tags for 1
Router(config)# tag-switching advertise-tags for 4

In the following example, the router is configured to advertise all tags to all TDP neighbors except neighbor 10.101.0.8.

Router(config)# access-list 1 permit any 
Router(config)# access-list 2 deny  10.101.0.8 
Router(config)# tag-switching advertise-tags 
Router(config)# tag-switching advertise-tags for 1 to 2

tag-switching atm allocation-mode

To control the mode used for handling tag binding requests on TC-ATM interfaces, use the tag-switching atm allocation-mode global configuration command. Use the no form of this command to disable this feature.

tag-switching atm allocation-mode {optimistic | conservative}
no tag-switching atm allocation-mode {optimistic | conservative}

Syntax Description

optimistic	Tag binding is returned immediately and packets are discarded until the downstream setup is complete.
conservative	Tag binding is delayed until the tag VC has been set up downstream.

Defaults

The default is conservative.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

In the following example, the mode for handling binding requests is set to optimistic on a TC-ATM interface:

tag-switching atm allocation-mode optimistic

tag-switching atm control-vc

To configure the VPI and VCI to be used for the initial link to the Tag Switching peer device, use the tag-switching atm control-vc interface configuration command. The initial link is used to establish the TDP session and to carry non-IP traffic. To clear the interface configuration, use the no form of this command.

tag-switching atm control-vc vpi vci
no tag-switching atm control-vc vpi vci

Syntax Description

vpi	Virtual path identifier.
vci	Virtual channel identifier.

Defaults

If the subinterface has not changed to a VP tunnel, the default is 0/32. If the subinterface corresponds to VP tunnel VPI X, the default is X/32.

Command Modes

Interface configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

For a router interface (for example, an AIP) ATM Tag Switching can be enabled only on a tag-switch subinterface.

Note The tag-switching atm control-vc and tag-switching atm vpi subinterface level configuration commands are available on any interface that can support ATM tagging.

On the Cisco LightStream 1010 ATM switch, a subinterface corresponds to a VP tunnel, so the VPI field of the control-vc must match the VPI field of the VP tunnel.

Examples

The following creates a Tag Switching subinterface on a router and selects VPI 1 and VCI 34 as the control VC:

interface atm4/0.1 tag-switching
 tag-switching ip
 tag-switching atm control-vc 1 34

Related Commands

Command	Description
show tag-switching atm-tdp capability	Displays the ATM TDP tag capabilities.
show tag-switching interfaces	Displays information about one or more interfaces that have Tag Switching enabled.

tag-switching atm maxhops

To limit the maximum hop counts to a value you have specified, use the tag-switching atm maxhops global configuration command. Use the no form of this command to ignore the hop count.

tag-switching atm maxhops [number]
no tag-switching atm maxhops

Syntax Description

number

(Optional) Maximum hop count.

Defaults

The default is 254.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

When an ATM TSR receives a BIND REQUEST, it does not send a BIND back if the value in the request is equal to the maxhops value. Instead, the ATM TSR or TSR returns an error that specifies that the hop count has been reached.

When an ATM-TSR initiates a request for a tag binding, it includes a parameter specifying the maximum number of hops that the request should travel before reaching the edge of the ATM Tag Switching region. This is used to prevent forwarding loops in setting up tag paths across the ATM region.

Examples

The following example sets the hop count limit to 2:

tag-switching atm maxhops 2

Related Commands

Command	Description
show tag-switching atm-tdp bindings	Displays the requested entries from the ATM TDP tag binding database.

tag-switching atm vc-merge

To control whether vc-merge (multipoint-to-point) is supported for unicast tag VCs, use the tag-switching atm vc-merge global configuration command. Use the no form of this command to disable this feature.

tag-switching atm vc-merge
no tag-switching atm vc-merge

Syntax Description

This command has no arguments or keywords.

Defaults

The default is enabled if the hardware supports the ATM-VC merge capability.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

The following example disables VC merge:

no tag-switching atm vc-merge

Related Commands

Command	Description
show tag-switching atm-tdp capability	Displays the ATM TDP tag capabilities.

tag-switching atm vpi

To configure the range of values to use in the VPI field for tag VCs, use the tag-switching atm vpi interface configuration command. To clear the interface configuration, use the no form of this command.

tag-switching atm vpi vpi [- vpi]
no tag-switching atm vpi vpi [- vpi]

Syntax Description

vpi	Virtual path identifier (low end of range).
- vpi	(Optional) Virtual path identifier (high end of range).

Defaults

The default is 1-1.

Command Modes

Interface configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

To configure ATM Tag Switching on a router interface (for example, an ATM Interface Processor), you must enable a Tag Switching subinterface.

Note The tag-switching atm control-vc and tag-switching atm vpi interface configuration commands are available on any interface that can support ATM tagging.

Use this command to select an alternate range of VPI values for ATM tag assignment on this interface. The two ends of the link negotiate a range defined by the intersection of the range configured at each end.

Examples

The following example creates a subinterface and selects a VPI range from VPI 1 to VPI 3:

interface atm4/0.1 tag-switching
 tag-switching ip
 tag-switching atm vpi 1-3

Related Commands

Command	Description
tag-switching atm control-vc	Configures the VPI and VCI to be used for the initial link to the Tag Switching peer device.

tag-switching ip (global configuration)

To allow Tag Switching of IPv4 packets, use the tag-switching ip global configuration command. To disable IP Tag Switching across all interfaces, use the no form of this command.

tag-switching ip
no tag-switching ip

Syntax Description

This command has no arguments or keywords.

Defaults

Tag Switching of IPv4 packets is allowed.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

Dynamic Tag Switching (that is, distribution of tags based on routing protocols) is allowed by this optional command, but it is not actually enabled until the interface-level tag-switching ip command is issued on at least one interface. The no form of this command stops the distribution of dynamic tags, and the sending of outgoing tagged packets on all interfaces. The command does not affect the sending of tagged packets through TSP tunnels.

For a TC-ATM interface, the no form of this command prevents the establishment of tag VCs beginning at, terminating at, or passing through the platform.

Examples

The following example prevents the distribution of dynamic tags on all interfaces:

configure terminal
no tag-switching ip

Related Commands

Command	Description
tag-switching ip (interface configuration)	Enables Tag Switching of IPv4 packets on an interface.

tag-switching ip (interface configuration)

To enable Tag Switching of IPv4 packets on an interface, use the tag-switching ip interface configuration command. To disable IP Tag Switching on this interface, use the no form of this command.

tag-switching ip
no tag-switching ip

Syntax Description

This command has no arguments or keywords.

Defaults

Tag Switching of IPv4 packets is disabled on this interface.

Command Modes

Interface configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

The first time this command is issued on any interface, dynamic Tag Switching is enabled on the router as a whole. TDP hello messages are issued on this interface. When an outgoing tag for a destination routed out through this interface is received, packets sent to that destination are assigned with that tag.

The no form of this command causes packets routed out through this interface to be sent untagged, and outgoing TDP hello messages are no longer sent.

When the no form is issued on the only interface of a router for which Tag Switching was enabled, dynamic Tag Switching is disabled on the router as a whole.

For a TC-ATM interface, the no form of this command prevents the establishment of tag VCs beginning at, terminating at, or passing through the platform.

Examples

The following example, enables Tag Switching on the specified Ethernet interface:

configure terminal
interface e0/2
tag-switching ip

Related Commands

Command	Description
tag-switching advertise-tags	Controls the distribution of locally assigned (incoming) tags through the TDP.
show tag-switching interfaces	Displays information about one or more interfaces that have Tag Switching enabled.

tag-switching ip default-route

To enable the distribution of tags associated with the IP default route, use the tag-switching ip default-route global configuration command.

tag-switching ip default-route

Syntax Description

This command has no arguments or keywords.

Defaults

No distribution of IP default routes.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

Dynamic Tag Switching (that is, distribution of tags based on routing protocols) must be enabled before you can use the tag-switching ip default-route command.

Examples

The following commands enable the distribution of tags associated with the IP default route:

configure terminal
tag-switching ip
tag-switching ip default-route

Related Commands

Command	Description
tag-switching ip (interface configuration)	Enables Tag Switching of IPv4 packets on an interface.
tag-switching ip (Global configuration)	Allows Tag Switching of IPv4 packets across all interfaces.

tag-switching mtu

To override the per-interface maximum transmission unit (MTU), use the tag-switching mtu interface configuration command. To restore the default, use the no form of this command.

tag-switching mtu bytes
no tag-switching mtu

Syntax Description

bytes

MTU in bytes.

Defaults

Minimum is 128 bytes; maximum depends on interface medium type.

Command Modes

Interface configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

If a tagged IP packet exceeds the MTU set for the interface, the Cisco IOS software will fragment it. All devices on a physical medium must have the same protocol MTU in order to operate.

Note Changing the MTU value (with the mtu interface configuration command) can affect the tag IP MTU value. If the current tag IP MTU value is the same as the MTU value, and you change the MTU value, the tag IP MTU value will be modified automatically to match the new MTU. However, the reverse is not true; changing the tag IP MTU value has no effect on the value for the mtu command.

Examples

The following example sets the maximum tagged packet size for the first serial interface to 300 bytes:

interface serial 0
 tag-switching mtu 300

tag-switching tag-range downstream

To configure the size of the tag space for downstream unicast tag allocation, use the tag-switching tag-range downstream global configuration command. Use the no form of this command to revert to the platform defaults.

tag-switching tag-range downstream min max reserved
no tag-switching tag-range downstream min max reserved

Syntax Description

min	The smallest tag allowed in the tag space. The default is 10.
max	The largest tag allowed in the tag space. The default is 10000.
reserved	The number of tags reserved for diagnostic purposes. These tags come out of the low end of the tag space. Default is 16.

Defaults

The default values for the parameters just listed are as follows:

: min---10
max---10000
reserved---16

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

The following example shows how to configure the size of the tag space for downstream unicast tag allocation. In the example, min is set with the value of 10, max is set with the value of 12000, and reserved is set with the value of 16.

configure terminal
tag-switching tag-range downstream 10 12000 16

Related Commands

Command	Description
show tag-switching tdp parameters	Displays available TDP parameters.

tag-switching tdp discovery

To configure the interval between transmission of TDP discovery hello messages, or the hold time for a TDP transport connection, use the tag-switching tdp discovery global configuration command.

tag-switching tdp discovery {hello | directed hello} {holdtime | interval} seconds

Syntax Description

hello	Configures the intervals and hold times for directly connected neighbors.
directed-hello	Configures the intervals and hold times for neighbors that are not directly connected (for example, TDP sessions that run through a TSP tunnel).
holdtime	The interval for which a connection stays up if no hello messages are received. The default is 15 seconds.
interval	The period between the sending of consecutive hello messages. The default is 5 seconds.
seconds	The hold time or interval.

Defaults

The default values for holdtime and interval are

: holdtime---15 seconds
interval---5 seconds

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Examples

In the following example, the interval for which a connection stays up if no hello messages are received is set to 5 seconds:

tag-switching tdp discovery hello holdtime 5

Related Commands

Command	Description
show tag-switching tdp parameters	Displays available TDP parameters.
tag-switching tdp holdtime	Enables TSP tunnel functionality on a device.

tag-switching tdp holdtime

To enable TSP tunnel functionality on a device, use the tag-switching tdp holdtime global configuration command.

tag-switching tdp holdtime seconds

Syntax Description

seconds

The time for which a TDP session is maintained in the absence of TDP messages from the session peer device.

Defaults

15 seconds.

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

When a TDP session is initiated, the hold time is set to the lower of the values configured at the two ends.

Examples

In the following example, the hold time of TDP sessions is configured for 30 seconds:

tag-switching tdp holdtime 30

Related Commands

Command	Description
show tag-switching tdp parameters	Displays available TDP parameters.
tag-switching tdp discovery	Configures the interval between transmission of TDP discovery hello messages.

tag-switching tsp-tunnels (global configuration)

To allow the operation of Tag-Switched Path (TSP) tunnels, use the tag-switching tsp-tunnels global configuration command. To disable the operation of TSP tunnels, use the no form of this command.

tag-switching tsp-tunnels
no tag-switching tsp-tunnels

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Global configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

TSP tunnel operation is allowed on the device by this optional command, but proper operation also requires that the interface-level tag-switching tsp-tunnels command be issued on the interfaces that are used by TSP tunnels. The no form of this command completely disables TSP tunnel operation on the device.

Examples

The following example allows TSP tunnel operation on a device:

configure terminal
ip cef distributed
tag-switching tsp-tunnels

Related Commands

Command	Description
ip cef	Enables CEF on the route processor card.
show tag-switching tsp-tunnels	Displays information about the configuration and status of selected tunnels.

tag-switching tsp-tunnels (interface configuration)

To allow TSP tunnel operation over an interface, use the tag-switching tsp-tunnels interface configuration command. To disable TSP tunnel operation over an interface, use the no form of this command.

tag-switching tsp-tunnels
no tag-switching tsp-tunnels

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Interface configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

TSP tunnel operation over a specific interface is allowed by this optional command. In order for TSP tunnels to operate over an interface, the tag-switching tsp-tunnels global configuration command must also be enabled. The no form of this command disables TSP tunnel operation over the specified interface.

Examples

The following example allows TSP tunnel operation over an interface:

configure terminal
ip cef distributed
tag-switching tsp-tunnels

Related Commands

Command	Description
ip cef	Enables CEF on the route processor card.
show tag-switching tsp-tunnels	Displays information about the configuration and status of selected tunnels.

traffic-engineering filter

To specify a filter with the given number and properties, use the traffic-engineering filter command. To disable this function, use the no form of this command.

traffic-engineering filter filter-number egress ip-address mask
no traffic-engineering filter

Syntax Description

filter-number	A decimal value representing the number of the filter.
egress ip-address mask	IP address and mask for the egress port.

Command Modes

Router configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

You must specify that the egress is the indicated address/mask, where egress is either the destination or the BGP next hop.

Examples

In the following example, configuration is provided for the traffic engineering routing process, a traffic engineering filter, and a traffic engineering route for that filter over a TSP-encapsulated tunnel:

router traffic-engineering
traffic-engineering filter 5 egress 83.0.0.1 255.255.255.255
traffic-engineering route 5 tunnel 5

Related Commands

Command	Description
show ip traffic-engineering routes	Displays information about the requested filters configured for traffic engineering.
traffic-engineering route	Configures a route for a specified filter, through a specified tunnel.

traffic-engineering route

To configure a route for a specified filter, through a specified tunnel, use the traffic-engineering route command. To disable this function, use the no form of this command.

traffic-engineering route filter-number interface [preference number] [loop-prevention {on | off}]
no traffic-engineering route filter-number interface [preference number] [loop-prevention {on | off}]

Syntax Description

filter-number	The number of the traffic engineering filter to be forwarded through the use of this traffic engineering route, if the route is installed.
interface	TSP-encapsulated tunnel on which traffic-passing filter should be sent, if this traffic engineering route is installed.
preference number	(Optional) This is a number between 1 and 255, with a lower value being more desirable. The default is 1.
loop-prevention	(Optional) This can be on or off. The default is on.

Defaults

The default values for the following parameters are

: preference---1
loop-prevention---on

Command Modes

Router configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1 CT.

The traffic engineering process is used to decide if a configured traffic engineering route should be installed in the forwarding table.

The first step is to determine if the route is up. If the route is enabled, the TSP tunnel interface is up, the loop prevention check is either disabled or passed, and the traffic engineering route is up.

If multiple routes for the same filter are up, a route is selected based on administrative preference.

If loop prevention is enabled, metrics are solicited from the tunnel tail, and the loop prevention algorithm is run on the result. For a discussion of the loop prevention algorithm, see the show ip traffic-engineering metrics command.

Examples

router traffic-engineering
traffic-engineering filter 5 egress 83.0.0.1 255.255.255.255
traffic-engineering route 5 tunnel 5

Related Commands

Command	Description
show ip traffic-engineering configuration	Displays information about configured traffic engineering filters and routes.
show ip traffic-engineering routes	Displays information about the requested filters configured for traffic engineering.

tunnel mode tag-switching

To set the encapsulation mode of the tunnel to Tag Switching, use the tunnel mode tag-switching interface configuration command. Use the no form of this command to set the tunneling encapsulation mode to the default, Generic Routing Encapsulation (GRE).

tunnel mode tag-switching
no tunnel mode tag-switching

Syntax Description

This command has no arguments or keywords.

Command Modes

Interface configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1 CT.

A tunnel interface number must be less than or equal to 65535.

The tunnel mode tag-switching command fails if the interface number is invalid for a TSP tunnel identifier.

Examples

In the following example, the tunnel mode is set to Tag Switching:

interface tunnel 5
tunnel mode tag-switching

Related Commands

Command	Description
tunnel tsp-hop	Defines hops in the path for the Tag Switching tunnel.

tunnel tsp-hop

To define hops in the path for the Tag Switching tunnel, use the tunnel tsp-hop interface configuration command. Use the no form of this command to remove these hops.

tunnel tsp-hop hop-number ip-address [lasthop]
no tunnel tsp-hop hop-number ip-address [lasthop]

Syntax Description

hop-number	The sequence number of the hop being defined in the path. The first number is 1, which identifies the hop just after the head hop.
ip-address	The IP address of the input interface on that hop.
lasthop	(Optional) Indicates that the hop being defined is the final hop in the path (the tunnel destination).

Defaults

No hops are defined.

Command Modes

Interface configuration

Command History

Release	Modification
11.1 CT	This command was introduced.

Usage Guidelines

The list of tunnel hops must specify a strict source route for the tunnel. In other words, the router at hop <N> must be directly connected to the router at hop <N>+1.

Examples

The following example shows the configuration of a two-hop tunnel. The first hop router/switch is 82.0.0.2, and the second and last hop is router/switch 81.0.0.2.

interface tunnel 5
 
tunnel mode tag-switching
ip unnumbered e0/1
tunnel tsp-hop 1 82.0.0.2
tunnel tsp-hop 2 81.0.0.2 lasthop

Related Commands

Command	Description
tunnel mode tag-switching	Sets the encapsulation mode of the tunnel to Tag Switching.

Field	Description
Prefix	Destination network and mask.
TDP id	The TDP identifier of the TDP peer device at the other end of the tunnel. The TDP peer device advertises these metrics to this neighbor.
metric	The routing protocol and metric within that protocol for the prefix in question.
type	For metrics being requested by this device, the type is either request or release. For metrics being requested from this device, the type is advertise.
flags	For metrics being requested by this device metric-received indicates that the other end has responded with a metric value. For metrics being requested from this device, response-pending indicates that the metric value has not yet been sent to the requester.
rev	An internal identifier for the metric request or advertisement. The rev number is assigned when the request/advertisement is created. The rev number is updated if the local information for the metric changes.
refcnt	For a metric of type request, the number of traffic engineering routes interested in this metric value. Otherwise, refcnt is 1.

Field	Description
Destination:	Destination (network/mask)
Tailend Router	Types of VC. Options are Tailend---VC that terminates at this router Headend---VC that originates at this router Transit---VC that passes through a switch
ATM1/0.1	Interface.
1/35	VPI/VCI.
Active	TVC state: Active---Set up and working. Bindwait---Waiting for response. Remote Resource Wait---Waiting for resources (VPI/VCI space) to be available on the downstream device. Parent Wait---Transit VC input side waiting for output side to become active.
VCD=2	Virtual circuit descriptor number.

Field	Description
Local tag	Tag assigned by this router.
Outgoing tag or VC	Tag assigned by next hop, or VPI/VCI used to get to next hop. Some of the entries you can have in this column are [T] means forwarding through a TSP tunnel. "Untagged" means there is no tag for the destination from the next hop, or Tag Switching is not enabled on the outgoing interface. "Pop tag" means the next hop advertised an implicit NULL tag for the destination, and this router popped the top tag.
Prefix or Tunnel Id	Address or tunnel to which packets with this tag are going.
Bytes tag switched	Number of bytes switched with this incoming tag.
Outgoing interface	Interface through which packets with this tag are sent.
NextHop	IP address of neighbor that assigned the outgoing tag.
Mac/Encaps	Length in bytes of Layer 2 header, and length in bytes of packet encapsulation, including Layer 2 header and tag header.
MTU	Maximum transmission unit (MTU) of tagged packet.
Tag Stack	All the outgoing tags. If the outgoing interface is TC-ATM, the VCD is also shown.
00020900 00002000	The actual encapsulation in hexadecimal form. There is a space shown between Layer 2 and tag header.

Field	Description
Interface	Interface name.
IP	"Yes" if IP tagging has been enabled on this interface.
Tunnel	"Yes" if TSP tunnel tagging has been enabled on this interface.
Operational	Operational state. "Yes" if packets are being tagged.
MTU	Maximum number of data bytes per tagged packet that will be transmitted.

Field	Description
tib entry	Indicates that the following lines are the TIB entry for a particular destination (network/mask). The revision number is used internally to manage tag distribution for this destination.
remote binding	A list of outgoing tags for this destination learned from other Tag Switching Routers (TSRs). Each item on this list identifies the TSR from which the outgoing tag was learned and the tag itself. The TSR is identified by its TDP identifier.
imp-null	The implicit null tag. This tag value instructs the upstream router to pop the tag entry off the tag stack before forwarding the packet.

Field	Description
Peer TDP Ident	The TDP identifier of the neighbor (peer device) for this session.
Local TDP Ident	The TDP identifier for the local TSR for this session.
TCP connection	The TCP connection used to support the TDP session. The format for displaying the TCP connection is peer IP address.peer port local IP address.local port
State	The state of the TDP session. Generally this is Oper (operational), but transient is another possible state.
PIEs sent/rcvd	The number of TDP protocol information elements (PIEs) sent to and received from the session peer device. The count includes the transmission and receipt of periodic keep alive PIEs, which are required for maintenance of the TDP session.
Downstream	Indicates that the downstream method of tag distribution is being used for this TDP session. When the downstream method is used, a TSR advertises all of its locally assigned (incoming) tags to its TDP peer device (subject to any configured access list restrictions).
Downstream on demand	Indicates that the downstream on demand method of tag distribution is being used for this TDP session. When the downstream on demand method is used, a TSR advertises its locally assigned (incoming) tags to its TDP peer device only when the peer device asks for them.
Up time	The length of time the TDP session has existed.
TDP discovery sources	The source(s) of TDP discovery activity that led to the establishment of this TDP session.
Addresses bound to peer TDP Ident	The known interface addresses of the TDP session peer device. These are addresses that may appear as "next hop" addresses in the local routing table. They are used to maintain the Tag Forwarding Information Base (TFIB).

Field	Description
Protocol version	Indicates the version of the Tag Distribution Protocol (TDP) running on the platform.
Downstream tag pool	Describes the range of tags available for the platform to assign for Tag Switching. The tags available run from the smallest tag value (min tag) to the largest tag value (max tag), with a modest number of tags at the low end of the range (reserved tags) reserved for diagnostic purposes.
Session hold time	Indicates the time to maintain a TDP session with a TDP peer device without receiving TDP traffic or a TDP keep alive from the peer device.
keep alive interval	Indicates the interval of time between consecutive transmission TDP keep alive messages to a TDP peer device.
Discovery hello	Indicates the amount of time to remember that a neighbor platform wants a TDP session without receiving a TDP Hello from the neighbor (holdtime), and the time interval between transmitting TDP Hello messages to neighbors (interval).
Discovery directed hello	Indicates the amount of time to remember that a neighbor platform wants a TDP session when (1) the neighbor platform is not directly connected to the router and (2) the neighbor platform has not sent a TDP Hello message. The interval is known as holdtime. Also indicates the time interval between the transmission of Hello messages to a neighbor not directly connected to the router.
Accepting directed hellos	Indicates that the platform will accept and act on Directed TDP Hello messages (may not be present).

Field	Description
Signalling Summary	The status of the signalling and forwarding mechanism that is required in order for TSP tunnels to be signalled through the router.
TSP Tunnels Process	The status of the TSP tunnel signalling process. This process interacts with the signalling protocol to manage signalled tunnels and monitors the state of established tunnels.
RSVP Process	The status of the RSVP process. You use the RSVP protocol to signal tunnels.
Forwarding	The status of the forwarding mechanism used to switch data through local TSP tunnel segments.
TUNNEL ID	The identity of the tunnel being summarized as shown in the previous display output. The tunnel ID includes an IP address part and a number part, and is unique within the entire network.
DESTINATION	The destination of the TSP tunnel being summarized as shown in the previous display output---the IP address of the tunnel tail.
STATUS	The configuration status of the tunnel. At the head, this is an indication whether or not the tunnel has been completely configured. It also refers to the status of the associated software and hardware interfaces.
CONNECTION	The connection status of the tunnel. This is an indication whether or not the local signalling/configuration information shows that the tunnel is up. Typically the tunnel becomes "up" at the tail hop first, and then at the second to the last hop, and so forth until signalling brings it up at the first hop.

Table of Contents

Tag Switching Commands