MPLS VPN option C

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Jan 18th, 2008
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in option C we are using the neighbor a.b.c.d send-label on ASBRs... now what that command exactly does? is that generating new label? or it send the existing label... if yes then which one?

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arun kumar Sun, 01/20/2008 - 21:19
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The send-label command on e-BGP between ASBR's will generate labels for PE routers of two AS (PE-AS1 & PE-AS2 along with RR-AS1 & RR-AS2).

So when the traffic flows between NNI (ASBR's) traffic will flow with two labels.

First one is the label for PE-AS1 or PE-AS2 learned via BGP with send-label command(depends how the traffic flow)

Second label is for VPNV4 prefixes (which is exchanged via RR-AS1 and RR-AS2).

Without send-label command the traffic between ASBR's will flow only with inner label and ASBR's will not have any knowledge about VPN labels and LSP break will happen...

Hope this helps.. Pls rate if u find this useful...


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