Re: Route Limiting (summarization)

From: Sage Vadi (sagevadi@yahoo.co.uk)
Date: Sat Jan 11 2003 - 02:38:06 GMT-3


Hi Nathan,

With an IGP we can create summary-addresses, with BGP
we can use the aggregate attribute.

It seems to me by your question you are probably
tinkering with BGP, and that means supress-maps if you
are talking about ACLs/PLs.

Here is an example of summarization wiht supress-maps
in BGP.

router bgp 4
~cut~
aggregate-address 132.0.0.0 255.0.0.0 suppress-map
AGGREGATE <-- suppress based on PERMIT ACL
~
!
ip access-list standard AGGREGATE
permit 132.108.10.0 0.0.0.255 <-- note it is PERMIT
NOT deny, PERMIT, PERMIT!!!
!
route-map AGGREGATE permit 10
match ip address AGGREGATE <-- match ACL AGGREGATE
!

* 132.0.0.0/8 162.108.10.5 0 4 i <-- aggregate
* 132.108.4.0/22 162.108.10.5 0 4 1 ? <-- one
specific, NB: has denied 132.108.10.0/24 being
advertised

NB: you might want to read up on IGP/BGP
summarization.

Cheers,
Sage



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