The IS-IS Support for MTR feature provides Intermediate System-to-Intermediate System (IS-IS) support for multiple logical topologies over a single physical network. This module describes how to configure IS-IS for Multitopology Routing (MTR).
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.
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Prerequisites for IS-IS Support for MTR
Be familiar with the concepts in the "Routing Protocol Support for MTR" section.
Configure and activate a global topology configuration.
Activate a Multitopology Routing (MTR) topology on an Intermediate System-to-Intermediate System (IS-IS) device.
Configure the MTR topology to globally configure all interfaces by using the
all-interfaces address family topology configuration command, or configure the IS-IS topology in interface configuration mode to configure only IS-IS interfaces. The order in which you perform the two tasks does not matter.
Restrictions for IS-IS Support for MTR
Only the IPv4 address family (multicast and unicast) and IPv6 address family unicast are supported. For information about configuring Multitopology IS-IS for IPv6, see the
IS-IS Configuration Guide.
You must enable IP routing on the router for MTR to operate. MTR supports static and dynamic routing in Cisco IOS software. You can enable dynamic routing per-topology to support inter-domain and intra-domain routing. Route calculation and forwarding are independent for each topology. MTR support is integrated into Cisco IOS software for the following protocols:
Integrated Intermediate System-to-Intermediate System (IS-IS)
Open Shortest Path First (OSPF)
You apply the per-topology configuration in router address family configuration mode of the global routing process (router configuration mode). The address family and subaddress family are specified when entering address-family configuration mode. You specify the topology name and topology ID by entering the
topology command in address-family configuration mode.
You configure each topology with a unique topology ID under the routing protocol. The topology ID is used to identify and group NLRI for each topology in updates for a given protocol. In OSPF, EIGRP, and IS-IS, you enter the topology ID during the first configuration of the
topology command for a class-specific topology. In BGP, you configure the topology ID by entering the
bgp tid command under the topology configuration.
You can configure class-specific topologies with different metrics than the base topology. Interface metrics configured on the base topology can be inherited by the class-specific topology. Inheritance occurs if no explicit inheritance metric is configured in the class-specific topology.
You configure BGP support only in router configuration mode. You configure Interior Gateway Protocol (IGP) support in router configuration mode and in interface configuration mode.
By default, interfaces are not included in non-base topologies. For routing protocol support for EIGRP, IS-IS, and OSPF, you must explicitly configure a non-base topology on an interface. You can override the default behavior by using the
all-interfaces command in address family topology configuration mode. The
all-interfaces command causes the non-base topology to be configured on all interfaces of the router that are part of the default address space or the VRF in which the topology is configured.
Interface Configuration Support for MTR
The configuration of a Multitopology Routing (MTR) topology in interface configuration mode allows you to enable or disable MTR on a per-interface basis. By default, a class-specific topology does not include any interfaces.
You can include or exclude individual interfaces by configuring the
topology interface configuration command. You specify the address family and the topology (base or class-specific) when entering this command. The subaddress family can be specified. If no subaddress family is specified, the unicast subaddress family is used by default.
You can include globally all interfaces on a device in a topology by entering the
all-interfaces command in routing topology configuration mode. Per-interface topology configuration applied with the
topology command overrides global interface configuration.
The interface configuration support for MTR has these characteristics:
Per-interface routing configuration: Interior Gateway Protocol (IGP) routing and metric configurations can be applied in interface topology configuration mode. Per-interface metrics and routing behaviors can be configured for each IGP.
Open Shortest Path First (OSPF) interface topology configuration: Interface mode OSPF configurations for a class-specific topology are applied in interface topology configuration mode. In this mode, you can configure an interface cost or disable OSPF routing without removing the interface from the global topology configuration.
Enhanced Interior Gateway Routing Protocol (EIGRP) interface topology configuration: Interface mode EIGRP configurations for a class-specific topology are applied in interface topology configuration mode. In this mode, you can configure various EIGRP features.
Intermediate System-to-Intermediate System (IS-IS) interface topology configuration: Interface mode IS-IS configurations for a class-specific topology are applied in interface topology configuration mode. In this mode, you can configure an interface cost or disable IS-IS routing without removing the interface from the global topology configuration.
Be familiar with the concepts in the Routing Protocol Support for MTR section.
Configure and activate a global topology configuration.
Activate an MTR topology on an IS-IS router.
Configure the MTR topology to globally configure all interfaces using the
all-interfaces address family topology configuration command, or configure the IS-IS topology in interface configuration mode to configure only IS-IS interfaces. The order in which you perform the two tasks does not matter.
Note
Only the IPv4 address family (multicast and unicast) and IPv6 address family unicast are supported. For information about configuring Multitopology IS-IS for IPv6, see the Implementing IS-IS for IPv6 module in the
Cisco IOS IPv6 Configuration Guide.
Configures an MTR topology instance on an interface.
Note
In this example, the topology instance VOICE is configured for an MTR network that has a global topology named VOICE.
Step 9
end
Example:
Router(config-if-topology)# end
Exits interface topology configuration mode and returns to privileged EXEC mode.
Monitoring Interface and Topology IP Traffic Statistics for MTR
Use any of the following commands in any order to monitor interface and topology IP traffic statistics for Multitopology Routing (MTR).
SUMMARY STEPS
1.enable
2.show ip interface [type number] [topology {name |
all |
base}] [stats]
3.show ip traffic [topology {name |
all |
base}]
4.clear ip interfacetype number [topology {name |
all |
base}] [stats]
5.clear ip traffic [topology {name |
all |
base}]
DETAILED STEPS
Command or Action
Purpose
Step 1
enable
Example:
Device> enable
Enables privileged EXEC mode.
Enter your password if prompted.
Step 2
show ip interface [type number] [topology {name |
all |
base}] [stats]
Example:
Device# show ip interface FastEthernet 1/10 stats
(Optional) Displays IP traffic statistics for all interfaces or statistics related to the specified interface.
If you specify an interface type and number, information for that specific interface is displayed. If you specify no optional arguments, information for all the interfaces is displayed.
If the
topologyname keyword and argument are used, statistics are limited to the IP traffic for that specific topology.
The
base keyword displays the IPv4 unicast base topology.
Step 3
show ip traffic [topology {name |
all |
base}]
Example:
Device# show ip traffic topology VOICE
(Optional) Displays global IP traffic statistics (an aggregation of all the topologies when MTR is enabled) or statistics related to a particular topology.
The
base keyword is reserved for the IPv4 unicast base topology.
Step 4
clear ip interfacetype number [topology {name |
all |
base}] [stats]
Example:
Device# clear ip interface FastEthernet 1/10 topology all
(Optional) Resets interface-level IP traffic statistics.
If the
topology keyword and a related keyword are not used, only the interface-level aggregate statistics are reset.
If all topologies need to be reset, use the
all keyword as the topology name.
Step 5
clear ip traffic [topology {name |
all |
base}]
Example:
Device# clear ip traffic topology all
(Optional) Resets IP traffic statistics.
If no topology name is specified, global statistics are cleared.
Examples Activating an MTR Topology by Using IS-IS
The following example shows how to configure both the MTR topologies DATA and VIDEO and IS-IS support for MTR. The DATA and VIDEO topologies are enabled on three IS-IS neighbors in a network.
Router1
global-address-family ipv4
topology DATA
topology VOICE
end
interface Ethernet 0/0
ip address 192.168.128.2 255.255.255.0
ip router isis
topology ipv4 DATA
isis topology disable
topology ipv4 VOICE
end
router isis
net 33.3333.3333.3333.00
metric-style wide
address-family ipv4
topology DATA tid 100
topology VOICE tid 200
end
Router2
global-address-family ipv4
topology DATA
topology VOICE
all-interfaces
forward-base
maximum routes 1000 warning-only
shutdown
end
interface Ethernet 0/0
ip address 192.168.128.1 255.255.255.0
ip router isis
topology ipv4 DATA
isis topology disable
topology ipv4 VOICE
end
interface Ethernet 1/0
ip address 192.168.130.1 255.255.255.0
ip router isis
topology ipv4 DATA
isis topology disable
topology ipv4 VOICE
end
router isis
net 32.3232.3232.3232.00
metric-style wide
address-family ipv4
topology DATA tid 100
topology VOICE tid 200
end
Router 3
global-address-family ipv4
topology DATA
topology VOICE
all-interfaces
forward-base
maximum routes 1000 warning-only
shutdown
end
interface Ethernet 1/0
ip address 192.168.131.1 255.255.255.0
ip router isis
topology ipv4 DATA
isis topology disable
topology ipv4 VOICE
end
router isis
net 31.3131.3131.3131.00
metric-style wide
address-family ipv4
topology DATA tid 100
topology VOICE tid 200
end
Entering the showisisneighborsdetail command verifies topology translation with the IS-IS neighbor Router1:
Router# show isis neighbors detail
System Id Type Interface IP Address State Holdtime Circuit Id
R1 L2 Et0/0 192.168.128.2 UP 28 R5.01
Area Address(es): 33
SNPA: aabb.cc00.1f00
State Changed: 00:07:05
LAN Priority: 64
Format: Phase V
Remote TID: 100, 200
Local TID: 100, 200
Examples MTR IS-IS Topology in Interface Configuration Mode
The following example shows how to prevent the IS-IS process from advertising interface Ethernet 1/0 as part of the DATA topology:
interface Ethernet 1/0
ip address 192.168.130.1 255.255.255.0
ip router isis
topology ipv4 DATA
isis topology disable
topology ipv4 VOICE
end
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The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to
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Table 1
Feature Information for IS-IS Support for MTR
Feature Name
Releases
Feature Information
IS-IS Support for MTR
12.2(33)SRB
This feature provides Intermediate System-to-Intermediate System (IS-IS) support for multiple logical topologies over a single physical network.
The following commands were introduced or modified:
address-family ipv4,
isis topology disable,
show isis neighbors,
topology.
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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.