[c-nsp] MPLS VPN Problem - EoS conflict

Ibrahim Abo Zaid ibrahim.abozaid at gmail.com
Tue Dec 23 05:23:24 EST 2008

Hi All

I was implementing MPLS VPN topology and by mistake i was configuring PE-LP
used for MP-BGP peering with a worng mask /24 instead of /32 (remote PE-LP
mask is /32) .

by T.S , i discovered that P router upstream of this PE was dropping
incoming MPLS packets with the below error message

tagsw_replace_header: Pkt drop -- EoS conflict, incg label 18 hwinput Fa0/0

discovering FIB

3#sh mpls forwarding-table | in 18

18     Untagged      1230       Se0/1      point2point

so when the mask was /24 , PE advertise label as untag label so incoming
traffic over MPLS interface will be conveted to IP traffic and looking up in
LFIB , it will forward it down MPLS interface to PE as native IP packet
while it should MPLS packet with label-3

I need to know why that happens ? , does LDP-Adv tells S-bit setting in
incoming packets according to label type ?

BTW , the problem solved after changing LO mask to /32 and it has been
advertised as Imp-Null

18     Pop tag      0          Se0/1      point2point

your responses is highly appreciated

best regards

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