IP Routing: ISIS Configuration Guide, Cisco IOS XE Release 3S (Cisco ASR 1000)
IS-IS IPv6 Administrative Tag
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IS-IS Support for an IS-IS Instance per VRF for IP

IS-IS IPv6 Administrative Tag

Last Updated: December 4, 2012

The IS-IS IPv6 Administrative Tag feature allows you to assign a tag to IPv6 prefixes that you can use to apply administrative policies with a route map. For example, you can control routes redistributed between area and domain boundaries and between different routing protocols, or apply policies on Intermediate System-to-Intermediate System (IS-IS) routes.

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Information About IS-IS IPv6 Administrative Tag

IS-IS Administrative Tags in IPv6 Prefixes

You can configure an IS-IS administrative tag value for IPv6 prefixes. You can then specify the tag value of IPv6 prefixes that IS-IS inserts into the link-state protocol data units (PDUs) it generates and those that it retrieves from LSPs.

How to Configure an IS-IS IPv6 Administrative Tag

Assigning a Tag to an IS-IS IPv6 Prefix

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router isis [area-tag]

4.    net net1

5.    metric-style wide

6.    interface [type number]

7.    ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}

8.    ipv6 router isis [area-tag]

9.    isis ipv6 tag tag-value

10.    end

11.    show isis database verbose


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Device> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Device# configure terminal

 

Enters global configuration mode.

 
Step 3
router isis [area-tag]


Example:

Device(config)# router isis tag13

 

Enables the IS-IS routing protocol, specifies an IS-IS process, and enters router configuration mode.

 
Step 4
net net1


Example:

Device(config-router)# net 49.0000.0000.0100.00

 

Configures an IS-IS network entity table (NET) for the routing process.

 
Step 5
metric-style wide


Example:

Device(config-router)# metric-style wide

 
Configures a router running IS-IS so that it generates and accepts only new-style type, length, value objects (TLVs).  
Step 6
interface [type number]


Example:

Device(config-router)# interface GigabitEthernet 0/0/0

 

Configures an interface and enters interface configuration mode.

 
Step 7
ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}


Example:

Device(config-if)# ipv6 address 2005::1/64

 

Configures an IPv6 address based on an IPv6 general prefix and enables IPv6 processing on an interface.

 
Step 8
ipv6 router isis [area-tag]


Example:

Device(config-if)# ipv6 router isis area1

 

Configures an IS-IS routing process for IPv6 on an interface and attaches an area designator to the routing process.

 
Step 9
isis ipv6 tag tag-value


Example:

Device(config-if)# isis ipv6 tag 200

 

Configures an administrative tag value that will be associated with an IPv6 address prefix and applied to an IS-IS LSP.

 
Step 10
end


Example:

Device(config-if)# end

 

(Optional) Saves configuration commands to the running configuration file and returns to privileged EXEC mode.

 
Step 11
show isis database verbose


Example:

Device# show isis database verbose

 

(Optional) Displays details about the IS-IS link-state database, including the route tag.

  • Enter this command if you want to verify the tag.
 

Assigning a High Priority Administrative Tag to an IS-IS IPv6 Prefix

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router isis [area-tag]

4.    address-family ipv6

5.    ipv6 route priority high tag tag-value

6.    exit

7.    exit


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Device> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Device# configure terminal

 

Enters global configuration mode.

 
Step 3
router isis [area-tag]


Example:

Device(config)# router isis

 

Configures an IS-IS routing process for IP on an interface, attaches an area designator to the routing process, and enters router configuration mode.

 
Step 4
address-family ipv6


Example:

Device(config-router)# address-family ipv6

 

Enters address family configuration mode.

 
Step 5
ipv6 route priority high tag tag-value


Example:

Device(config-router-af)# ipv6 route priority high tag 200

 

Assigns a high priority tag to an IS-IS IPv6 prefix.

 
Step 6
exit


Example:

Device(config-router-af)# exit

 

(Optional) Exits address family configuration mode, and returns to router configuration mode.

 
Step 7
exit


Example:

Device(config-router)# exit

 

(Optional) Exits router configuration mode, and returns to global configuration mode.

 

Using an IS-IS IPv6 Administrative Tag to Redistribute Routes

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router isis [area-tag]

4.    address-family ipv6

5.    redistribute isis [process-id] {level-1 | level-2} into {level-1 | level-2} [distribute-list list-name] [route-map map-tag]

6.    exit

7.    exit

8.    route-map map-tag [permit | deny] [sequence-number]

9.    match tag tag-value [...tag-value]

10.    exit


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Device> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Device# configure terminal

 

Enters global configuration mode.

 
Step 3
router isis [area-tag]


Example:

Device(config)# router isis

 

Configures an IS-IS routing process for IP on an interface, attaches an area designator to the routing process, and enters router configuration mode.

 
Step 4
address-family ipv6


Example:

Device(config-router)# address-family ipv6

 

Enters address family configuration mode.

 
Step 5
redistribute isis [process-id] {level-1 | level-2} into {level-1 | level-2} [distribute-list list-name] [route-map map-tag]


Example:

Device(config-router-af)# redistribute isis level-1 into level-2 route-map IPV6-PERMIT-TAG

 

Redistributes IPv6 routes from one routing domain into another routing domain using IS-IS as both the target and source protocol.

 
Step 6
exit


Example:

Device(config-router-af)# exit

 

(Optional) Exits address family configuration mode, and returns to router configuration mode.

 
Step 7
exit


Example:

Device(config-router)# exit

 

(Optional) Exits router configuration mode, and returns to global configuration mode.

 
Step 8
route-map map-tag [permit | deny] [sequence-number]


Example:

Device(config)# route-map match-tag

 

Defines the conditions for redistributing routes from one routing protocol into another or from one IS-IS level to another.

  • This command causes the router to enter route-map configuration mode.
 
Step 9
match tag tag-value [...tag-value]


Example:

Device(config-route-map)# match tag 100

 

Matches routes tagged with the specified tag numbers.

  • If you are setting a tag for the first time, you cannot match on tag; this step is an option if you are changing tags.
 
Step 10
exit


Example:

Device(config-route-map)# exit

 

(Optional) Exits route-map configuration mode, and returns to global configuration mode.

 

Using an IS-IS IPv6 Administrative Tag to Configure Routes

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 route [vrf vrf-name] ipv6-prefix/prefix-length {ipv6-address | interface-type interface-number [ipv6-address]} [nexthop-vrf [vrf-name | default]] [administrative-distance] [administrative-multicast-distance | unicast | multicast] [next-hop-address] [tag tag]

4.    router isis [area-tag]

5.    address-family ipv6

6.    redistribute isis [process-id] {level-1 | level-2} into {level-1 | level-2} [distribute-list list-name] [route-map map-tag

7.    exit

8.    exit

9.    route-map map-tag [permit | deny] [sequence-number]

10.    set tag tag-value

11.    exit


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Device> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Device# configure terminal

 

Enters global configuration mode.

 
Step 3
ipv6 route [vrf vrf-name] ipv6-prefix/prefix-length {ipv6-address | interface-type interface-number [ipv6-address]} [nexthop-vrf [vrf-name | default]] [administrative-distance] [administrative-multicast-distance | unicast | multicast] [next-hop-address] [tag tag]


Example:

Router(config)# ipv6 route 2033::1/64 GigabitEthernet 0/0/0

 

Establishes a static IPv6 routes.

 
Step 4
router isis [area-tag]


Example:

Device(config)# router isis

 

Configures an IS-IS routing process for IP on an interface, attaches an area designator to the routing process, and enters router configuration mode.

 
Step 5
address-family ipv6


Example:

Device(config-router)# address-family ipv6

 

Enters address family configuration mode.

 
Step 6
redistribute isis [process-id] {level-1 | level-2} into {level-1 | level-2} [distribute-list list-name] [route-map map-tag


Example:

Device(config-router-af)# redistribute isis level-1 into level-2 route-map IPV6-PERMIT-TAG

 

Redistributes IPv6 routes from one routing domain into another routing domain using IS-IS as both the target and source protocol.

 
Step 7
exit


Example:

Device(config-router-af)# exit

 

(Optional) Exits address family configuration mode, and returns to router configuration mode.

 
Step 8
exit


Example:

Device(config-router)# exit

 

(Optional) Exits router configuration mode, and returns to global configuration mode.

 
Step 9
route-map map-tag [permit | deny] [sequence-number]


Example:

Router(config)# route-map set-tag

 

Defines the conditions for redistributing routes from one routing protocol into another or from one IS-IS level to another.

  • This command causes the router to enter route-map configuration mode.
 
Step 10
set tag tag-value


Example:

Router(config-route-map)# set tag 300

 

Sets a tag value of the destination routing protocol.

 
Step 11
exit


Example:

Device(config-route-map)# exit

 

(Optional) Exits route-map configuration mode, and returns to global configuration mode.

 

Applying an IS-IS IPv6 Tag to a Summary Prefix

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    router isis [area-tag]

4.    address-family ipv6

5.    ipv6 route [vrf vrf-name] ipv6-prefix / prefix-length {ipv6-address | interface-type interface-number [ipv6-address]} [nexthop-vrf [vrf-name | default]] [administrative-distance] [administrative-multicast-distance | unicast | multicast] [next-hop-address] [tag tag]

6.    exit

7.    exit

8.    router isis [area-tag]

9.    address-family ipv6

10.    redistribute isis [process-id] {level-1| level-2} into {level-1 |level-2} distribute-list list-name

11.    summary-prefix ipv6-prefix/ prefix-length {level-1 | level-1-2| level-2} tag tag-value

12.    end

13.    show isis database verbose


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Device> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Device# configure terminal

 

Enters global configuration mode.

 
Step 3
router isis [area-tag]


Example:

Device(config)# router isis

 

Configures an IS-IS routing process for IP on an interface, attaches an area designator to the routing process, and enters router configuration mode.

 
Step 4
address-family ipv6


Example:

Device(config-router)# address-family ipv6

 

Enters address family configuration mode.

 
Step 5
ipv6 route [vrf vrf-name] ipv6-prefix / prefix-length {ipv6-address | interface-type interface-number [ipv6-address]} [nexthop-vrf [vrf-name | default]] [administrative-distance] [administrative-multicast-distance | unicast | multicast] [next-hop-address] [tag tag]


Example:

Device(config-router-af)# ipv6 route 11:1:1:1:1:1::/96 GigabitEthernet 0/0/0

 

Establishes a static IPv6 routes.

 
Step 6
exit


Example:

Device(config-router-af)# exit

 

(Optional) Exits address family configuration mode, and returns to router configuration mode.

 
Step 7
exit


Example:

Device(config-router)# exit

 

(Optional) Exits router configuration mode, and returns to global configuration mode.

 
Step 8
router isis [area-tag]


Example:

Device(config)# router isis

 

Configures an IS-IS routing process for IP on an interface, attaches an area designator to the routing process, and enters router configuration mode.

 
Step 9
address-family ipv6


Example:

Device(config-router)# address-family ipv6

 

Enters address family configuration mode.

 
Step 10
redistribute isis [process-id] {level-1| level-2} into {level-1 |level-2} distribute-list list-name


Example:

Device(config-router-af)# redistribute static level-2 metric 50

 

Redistributes IPv6 routes from one routing domain into another routing domain using IS-IS as both the target and source protocol.

 
Step 11
summary-prefix ipv6-prefix/ prefix-length {level-1 | level-1-2| level-2} tag tag-value


Example:

Device(config-router-af)# summary-prefix 11:1:1:1::/64 tag 600

 

Allows a Level 1-2 router to summarize Level 1 prefixes at Level 2, instead of advertising the Level 1 prefixes directly when the router advertises the summary.

  • The ipv6-prefix argument in the summary-prefix command must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.
  • The prefix-length argument is a decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). A slash mark must precede the decimal value.
 
Step 12
end


Example:

Device(config-router-af)# end

 

(Optional) Saves configuration commands to the running configuration file and returns to privileged EXEC mode.

 
Step 13
show isis database verbose


Example:

Device# show isis database verbose

 

(Optional) Displays details about the IS-IS link-state database, including the route tag.

  • Perform this step if you want to verify the tag.
 

Configuration Examples for IS-IS IPv6 Administrative Tag

Example: Assigning a Tag to an IS-IS IPv6 Prefix

Device(config)# router isis
Device(config-router)# net 49.0000.0000.0100.00
Device(config-router)# metric-style wide
Device(config-router)# interface GigabitEthernet 0/0/0
Device(config-if)# ipv6 address 2005::1/64
Device(config-if)# ipv6 router isis
Device(config-if)# isis ipv6 tag 200
Device(config-if)# end
Device# show isis database verbose

IS-IS Level-1 Link State Database:
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime      ATT/P/OL
Device.00-00     * 0x00000001   0xD27D        1189              0/0/0
  Area Address: 49
  NLPID:        0x8E 
  Hostname: Device
  IPv6 Address: 2005::1
  Metric: 10         IPv6 2005::/64
    Route Admin Tag: 200
IS-IS Level-2 Link State Database:
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime      ATT/P/OL
Device.00-00     * 0x00000001   0xD27D        1189              0/0/0
  Area Address: 49
  NLPID:        0x8E 
  Hostname: Device
  IPv6 Address: 2005::1
  Metric: 10         IPv6 2005::/64
    Route Admin Tag: 200    

      

Example: Assigning a High Priority Administrative Tag to an IS-IS IPv6 Prefix

Device(config)# router isis
Device(config-router)# address-family ipv6
Device(config-router-af)# ipv6 route priority high tag 200
      

Example: Using an IS-IS IPv6 Administrative Tag to Redistribute Routes

Device(config)# router isis
Device(config-router)# address-family ipv6
Device(config-router-af)# redistribute isis level-1 into level-2 route-map match-tag
Device(config-router-af)# route-map match-tag
Device(config-route-map)# match tag 100
      

Example: Using an IS-IS IPv6 Administrative Tag to Configure Routes

Device(config)# ipv6 route 2033::1/64 GigabitEthernet 0/0/0
Device(config)# router isis
Device(config-router)# address-family ipv6
Device(config-router-af)# redistribute static level-2 route-map set-tag
Device(config-router-af)# route-map set-tag
Device(config-route-map)# set tag 300
Device(config-route-map)# end
Device# show isis database verbose level-2

Device.00-00     * 0x0000004E   0x9805        1197              0/0/0
  Area Address: 33
  NLPID:        0xCC 0x8E 
  Hostname: Device
  IP Address:   10.100.100.20
  IPv6 Address: 2001:DB8::100
  IPv6 Address: 2001:DB8::200
  Metric: 10         IS-Extended route500.01
  Metric: 10         IP 10.100.100.0/24
  Metric: 10         IPv6 2001:DB8::/64
  Metric: 10         IPv6 2001:DB8::/64
  Metric: 10         IPv6-Interarea 11:1:1:1:1:1:1:1/128
  Metric: 20         IPv6-Interarea 2003:DB8::/64
  Metric: 0          IPv6 2033::/64
    Route Admin Tag: 300
      

Example: Applying an IS-IS IPv6 Administrative Tag to a Summary Prefix

Device(config)# router isis
Device(config)# ipv6 route 11:1:1:1:1:1::/96 GigabitEthernet 0/0/0
Device(config)# router isis
Device(config-router)# address-family ipv6
Device(config-router-af)# redistribute static level-2 metric 50
Device(config-router-af)# summary-prefix 11:1:1:1::/64 tag 600
Device(config-route-map)# end
Device# show isis database verbose level-2
 
IS-IS Level-2 Link State Database:
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime      ATT/P/OL
Device.00-00     * 0x00000007   0x4AA7        1174              0/0/0
  Area Address: 33
  NLPID:        0xCC 0x8E 
  Hostname: Device
  IP Address:   10.100.100.20
  IPv6 Address: 2001:DB8::100
  IPv6 Address: 2001:DB8::200
  Metric: 10         IS-Extended route500.01
  Metric: 10         IP 10.100.100.0/24
  Metric: 10         IPv6 2001:DB8::/64
  Metric: 10         IPv6 2001:DB8::/64
  Metric: 10         IPv6 11:1:1:1::/64
    Route Admin Tag: 600
(Summary route 11:1:1:1::/64 is advertised with tag 600)
Device(config-router-af)#
      

Additional References

Related Documents

Related Topic Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

IPv6 commands

Cisco IOS IPv6 Command Reference

Cisco IOS IPv6 features

Cisco IOS IPv6 Feature Mapping

Standards and RFCs

Standard/RFC Title

RFCs for IPv6

IPv6 RFCs

Technical Assistance

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Feature Information for IS-IS IPv6 Administrative Tag

Feature Name Releases Feature Information

IS-IS IPv6 Administrative Tag

15.2(4)M

Cisco IOS Release XE 3.6S

Allows you to assign a tag to IPv6 prefixes that you can use to apply administrative policy with a route map.

The following commands were introduced or modified: ipv6 route priority high, isis ipv6 tag, redistribute isis (ipv6), show isis database verbose, summary-prefix (ipv6 IS-IS).

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

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.

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