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prefix FEC advertised over targeted LDP session

I am doing MPLS L2VPN interop testing with foundry XMR, IOS establishes the targeted LDP session with XMR fine and VC FECs are exchanged. However, I noticed that IOS is also advertising prefix-FEC mappings to XMR. This is puzzling me, since there is no directly link between Cisco and XMR, LDP does not have a link neighborship between Cisco and XMR, why would IOS advertise prefix-FEC? IOS should know that the lables it advertises are never going to be used by a targeted peer. The targeted LDP session is meant for VC-FEC mapping exchange only.

XMR only advertises VC-FEC over this targeted LDP session unless link-hello is also heard from its peer, in which case, both prefix-fec and VC-fec are advertised

Cisco Employee

Re: prefix FEC advertised over targeted LDP session


This is the default behavior indeed and shouldn't cause any issue beyond the extra labels installed in the LIB.

You can easily change that behavior if you desire so by applying label filtering as follow:

no mpls ldp advertise-labels

mpls ldp advertise-labels for 1 to 2


access-list 1 permit any


access-list 2 deny

access-list 2 permit any

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
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