Targetted LDP sessions

[nisha_kulkarni]

Can someone please let me know something more abt Targetted LDP Sessions. All I know about it is that

Targeted LDP Sessions between nondirectly connected LSRs are supported using an extended discovery mechanism. Targeted hello messages are periodically sent to a specific IP address. The default HELLO

time for targeted LDP sessions is 45 seconds.

Some documentation with an example will be highly use for me.

Regards,

NISHA

[Harold Ritter · Accepted solution]

Targetted LDP sessions more or less like the regular LDP sessions, exception made that the UDP hellos are sent using a unicast IP address instead of a multicast address.

Targetted LDP sessions are mainly used for AToM to exchange VC labels or if LDP is used over TE tunnels.

Hope this helps,

[nisha_kulkarni]

Hi..

Okk I got what u mean to say..But when we talk of VPLS, is it so that we'll be using targetted LDP instead of normal LDP sessions ????

[romccallum]

yes. They shall be done automatically - just like EoMPLS in the point to point fashion.

[Harold Ritter]

When using VPLS, the targetted LDP session doesn't replace the normal (directly connected) LDP sessions. You still need LDP to run in the core to propagate IGP labels. The targetted LDP session on the other hand is used to exchange VC labels between the PEs.

Hope this helps,

[nisha_kulkarni]

Hi There...

Alrite..I got what mean to say...Now when we talk H-VPLS, we have something called as MTU (Multi tenant units) in order to reduce the burden of Full mesh between the PEs. Let's consider an e.g where a new PE joins the VPLS domain X. It is said that, only configuration between the new PE and it's respective MTU is needed. Now my question over here is, will u be running a targetted LDP or normal LDP sessions between the MTU and it's respective PE of that VPLS domain???

Regards,

NISHA

[Harold Ritter]

Actually, the multi tenant unit (aka the PE-CLE in H-VPLS terminology) doesn't use either LDP or targetted LDP with the PE.

QinQ (dot1q tunneling) is used between the PE-CLE and the PE to take many vlans coming from the customers and to encapsulate them in one vlan towards the SP core.

Please refer to the following to presentations for detailed information about VPLS.

http://www.cisco.com/warp/public/732/Tech/mpls/l2vpns/vpls/preso/

Hope this helps,

[nisha_kulkarni]

Hi...

Thanks for the info...

That solves my quesries...

NISHA