[c-nsp] Inter-AS option B - filter based on IPv4+ Labels?

Oliver Boehmer (oboehmer) oboehmer at cisco.com
Wed Aug 6 03:01:11 EDT 2008


Vikas Sharma <> wrote on Wednesday, August 06, 2008 5:00 AM:

>  Hi,
> 
> In Inter-AS - option B, I have an option of filtering with BGP
> attributes ASPATH, ext communities, RDs checks. Can I filter based on
> IPv4+ Labels? i.e. set route maps to filter and send only the
> desirable prefixes are injected into the BGP table and propagated
> using IPv4+ Labels to the adjacent ASBR? Can you point me the web
> page? 

you can filter on the IP prefix "part" of the vpnv4 RD:<prefix> update
(match ip address ...), however this filter ignores the RD so a "deny
10.0.0.1" would filter 10.0.0.1 from all vpns using this address.
If you have control over the vpn's address space (i.e. if those are your
"own" VPNs), it would be an option.

Filtering based on the VPN label is not possible (and would not make
sense as the label is dynamically allocated).

	oli


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