07-26-2009 02:38 PM
hi,
If two routers are forming LDP neighbor relationship but no label swapping is taking place.
Is is due to CEF or anything to do with BGP relationship between these neighbors.
Please share the experience.
Thanks in advance
Subodh
07-26-2009 03:41 PM
Hi Subodh,
no Labels are assigned to BGP routes. Labels are only assigned to directly connected routes and IGP-learned routes.
Please share your topology here.
07-26-2009 10:14 PM
Hi Subodh
You can also assign the labels with the help of BGP with in case of your scenario it is not required. If the basic configs are properly configured then it might be the issue of CEF. Please post the outputs of show mpls forwarding-table.
regards
shivlu jain
07-26-2009 11:03 PM
Hi Shivlu,
Of course, labels are assigned to BGP routes but only in MPLS VPN case running MP-iBGP.
07-27-2009 11:41 PM
Hello Amit,
>> Of course, labels are assigned to BGP routes but only in MPLS VPN case running MP-iBGP.
in some inter-AS or CSC scenarios you can use BGP to exchange labels the so called BGP with labels but it is an advanced topic.
usually if CEF is not enabled when you try to do sh mpls forwarding it clearly states CEF not running.
There are then some specific issues for example when using loopbacks for testing purposes with OSPF as IGP:
OSPF will try to advertise a /32 unless you configure
int loop m
ip ospf network point-to-point
LDP labels are installed if a corresponding prefix is found in CEF table and with the same outgoing interface/ IP next hop.
Hope to help
Giuseppe
07-28-2009 03:41 PM
Hi Giuseppe,
I am aware of Inter-AS/CSC where labels are forwarded using neighbor
In MP-eBGP (in case of BGP Confederation implementation), new labels can be assigned using next-hop-self command.
Actually, I replied keeping into perspective a single AS. I guess, I should have been more specific.
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