Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

bgp community number

when I do a sh ip bgp community ? I get the following on two routers.

route-views.oregon-ix.net>sh ip bgp community ?

aa:nn community number

local-AS Do not send outside local AS (well-known community)

no-advertise Do not advertise to any peer (well-known community)

no-export Do not export to next AS (well-known community)

| Output modifiers

<cr>

jo100-r5>sh ip bgp comm

jo100-r5>sh ip bgp community ?

<1-4294967295> community number

local-AS Do not send outside local AS (well-known community)

no-advertise Do not advertise to any peer (well-known community)

no-export Do not export to next AS (well-known community)

| Output modifiers

<cr>

one router has a community number <1-4294967295> and the other one has aa:nn

what is the difference? Is it IOS feature?

2 ACCEPTED SOLUTIONS

Accepted Solutions
Hall of Fame Super Silver

Re: bgp community number

Chandra

Yes it is an IOS feature. You can use the command ip bgp-community new-format to have the router format the community with the AS:value format.

HTH

Rick

Silver

Re: bgp community number

Yes, this is an IOS feature. The first router has what is called a "new format" of BGP community. They are both 32 bit numbers, but in "new format" the community is specified in "aa:nn" where "aa" is your AS number and "nn" is an arbitrary number. It was created for practival purposes, because 65000:1 was easier to write and manage than for example 3128683542.

To turn on or off the new format feature use "ip bgp-community new-format" global configuration command.

Hope this helps.

Please rate all helpful posts.

4 REPLIES
Hall of Fame Super Silver

Re: bgp community number

Chandra

Yes it is an IOS feature. You can use the command ip bgp-community new-format to have the router format the community with the AS:value format.

HTH

Rick

New Member

Re: bgp community number

Thanks, for the help

Silver

Re: bgp community number

Yes, this is an IOS feature. The first router has what is called a "new format" of BGP community. They are both 32 bit numbers, but in "new format" the community is specified in "aa:nn" where "aa" is your AS number and "nn" is an arbitrary number. It was created for practival purposes, because 65000:1 was easier to write and manage than for example 3128683542.

To turn on or off the new format feature use "ip bgp-community new-format" global configuration command.

Hope this helps.

Please rate all helpful posts.

Cisco Employee

Re: bgp community number

Chandrathilaka,

The following command is configured on the first but not on the second router:

R1(config)#ip bgp ?

new-format select aa:nn format for BGP community

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
431
Views
0
Helpful
4
Replies