Published On: August 6ᵗʰ, 2019 02:02

IP Routing: ISIS Configuration Guide, Cisco IOS XE Release 3S

The IS-IS IPv6 Advertise Passive Only feature allows you to configure the Intermediate System-to-Intermediate System (IS-IS) instance on a device to advertise only IPv6 prefixes that belong to passive interfaces and exclude other connected IPv6 prefixes.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and 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 module.

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Prerequisites for IS-IS IPv6 Advertise Passive Only

Before you can use the IS-IS IPv6 Advertise Passive Only feature to exclude IPv6 prefixes of connected networks from IS-IS link-state protocol (LSP) data unit advertisements, the integrated IS-IS routing protocol must be configured. See the “Configuring a Basic IS-IS Network” section of the IP Routing: ISIS Configuration Guide.

Information About IS-IS IPv6 Advertise Passive Only

IPv6 Prefixes Only Allowed on Passive Interfaces

You can configure the IS-IS instance on a device to allow only IPv6 prefixes that belong to passive interfaces in its LSP advertisements. This configuration reduces the number of IPv6 prefixes carried in the LSP advertisement.

How to Configure IS-IS IPv6 Advertise Passive Only

Configuring IS-IS Instances on a Device to Advertise Passive Interface IPv6 Prefixes Only

SUMMARY STEPS

1. enable

2. configure terminal

3. router isis [area-tag]

4. net net1

5. interface loopback number

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

7. exit

8. interface type number

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

10. ipv6 router isis [area-tag]

11. exit

12. router isis [area-tag]

13. passive-interface [default] type number

14. address-family ipv6

15. advertise passive-only

16. end


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 area1
 

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 net net1


Example:
Device(config-router)# net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
 

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

 
Step 5 interface loopback number


Example:
Device(config-router)# interface loopback 0
 

Configures a loopback interface and enters interface configuration mode.

 
Step 6 ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}


Example:
Device(config-if)# ipv6 address 2001:688:1001:1000::1/128
 

Sets a primary IPv6 address for an interface.

 
Step 7 exit


Example:
Device(config-if)# exit
 

Returns to global configuration mode.

 
Step 8 interface type number


Example:
Device(config)# interface FastEthernet 0/0
 

Configures an interface type and enters interface configuration mode.

 
Step 9 ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}


Example:
Device(config-if)# ipv6 address 2001:688:1001:100A::1/64
 

Configures an IPv6 address for the interface.

 
Step 10 ipv6 router isis [area-tag]


Example:
Device(config-if)# ipv6 router isis area1
 

Configures an IS-IS routing process for IPv6 on an interface, attaches an area designator to the routing process, and enters router configuration mode.

 
Step 11 exit


Example:
Device(config-if)# exit
 

Returns to global configuration mode.

 
Step 12 router isis [area-tag]


Example:
Device(config)# router isis area1
 

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 13 passive-interface [default] type number


Example:
Device(config-router)# passive-interface loopback 0
 

Disables sending routing updates on an interface.

 
Step 14 address-family ipv6


Example:
Device(config-router)# address-family ipv6
 

Enters address family configuration mode.

 
Step 15 advertise passive-only


Example:
Device(config-router-af)# advertise passive-only
 

Configures IS-IS to advertise only IPv6 prefixes that belong to passive interfaces.

 
Step 16 end


Example:
Device(config-router-af)# end
 

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

 

Configuration Examples for IS-IS IPv6 Advertise Passive Only

Example: Configuring IS-IS Instances on a Device to Advertise Only Passive Interfaces

Device> enable
Device# configure terminal
Device(config)# router isis area1
Device(config-router)# net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
Device(config-router)# interface loopback 0
Device(config-if)# ipv6 address 2001:688:1001:1000::1/128
Device(config-if)# exit
Device(config)# interface Ethernet 0/0
Device(config-if)# ipv6 address 2001:688:1001:100A::1/64
Device(config-if)# ipv6 router isis area1
Device(config-if)# exit
Device(config)# router isis area1
Device(config-router)# passive-interface loopback 0
Device(config-router)# address-family ipv6
Device(config-router-af)# advertise passive-only
      

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

IS-IS commands

Cisco IOS IS-IS Command Reference

Configuring the integrated IS-IS routing protocol

“Configuring a Basic IS-IS Network” module of the IP Routing: ISIS Configuration Guide

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

MIBs

MIB

MIBs Link

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http:/​/​www.cisco.com/​go/​mibs

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

Feature Information for IS-IS IPv6 Advertise Passive Only

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 www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Table 1 Feature Information for IS-IS IPv6 Advertise Passive Only

Feature Name

Releases

Feature Information

IS-IS IPv6 Advertise Passive Only

15.2(4)M

Cisco IOS XE Release 3.6S

Allows you to configure the IS-IS instance on a device to advertise only IPv6 prefixes that belong to passive interfaces and exclude other connected IPv6 prefixes.

The following command was introduced or modified: advertise passive-only (IPv6).