Giuseppe Larosa Mon, 02/02/2009 - 07:20
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

ello Wang,


the config files that you have tried to attach are not complete.


However, notice that a vpnv4 router can have mutiple RT attached to it.

So you need to verify if the route you see on R5 have multiple RTs


in that case you can have the answer.


to have an exact match that says if one of the RTs is xx:yy deny the route you should use extended extcommunity list


Hope to help

Giuseppe




shivlu jain Mon, 02/02/2009 - 08:47
User Badges:
  • Silver, 250 points or more

Giuseppe


Does cisco support more than 30 rt values attached in bgp update route?


regards

shivlu jain

Giuseppe Larosa Mon, 02/02/2009 - 10:19
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

Hello Shivlu,


according to RFC


http://www.ietf.org/rfc/rfc2858.txt


there is a byte wide field for the number of SNPAs (note I don't see any reference to route target here it is very general)


and a byte wide field to say how many bytes form a SNPA.


So it looks like possible to associate 30 RTs to a vpnv4 prefix but be aware that memory usage can grow very quicky.


see also


http://www.ietf.org/IESG/Implementations/mp-bgp-implementation-report.txt


this is not very new but provides info about different vendors implementations of MP-BGP.


But this is theory and implementation may put some limit to the number of RTs


Hope to help

Giuseppe


Harold Ritter Tue, 02/03/2009 - 14:18
User Badges:
  • Cisco Employee,

Giuseppe,


IOS would allow you to have up to 128 RT extended communities in one BGP update message. Bear in mind that the maximum BGP message size being 4096, it would not leave you much space for anything other than the extended communities.


Regards

Harold Ritter Tue, 02/03/2009 - 14:23
User Badges:
  • Cisco Employee,

Giuseppe,


Sorry, 128 is actually the old limitation. I just checked and the latest 12.0S code would allow in excess of 500 RT extended communities. I don't know if anyone would like to go that far though.


Regards

Actions

This Discussion