The MPLS WG Archive

["Chetan Pinto" <chetanpinto@hotmail.com>]

>Hi,
>
>In RFC3036 section 2.6.2.2 says
>     When operating in Downstream on Demand mode with liberal label 
>retention,
>an LSR might choose to request label mappings for all known prefixes from
>all peer LSRs.
>
>   As per my understanding there won't be any restriction when we learn any
>routes from IP and we obtain the mappings by sending Label Request for all
>the learnt FEC's (FEC aggregation/without aggregation) if we find the 
>required
>session/adjacenecy with the peer. So DoD acts as liberal in nature.......

Let us try to keep the "advertisement mode" and the "retention method"
separate. You can have a combination of DoD or DU with
Liberal or Conservative retention. Hence, DoD cannot be liberal by itself.

>
>   Does this mean any filtering is done for achieving conservative in DoD 
>or
>am I missing something........
If u are using DoD on a particular interface:
If using liberal retention, request labels for all FECs even
if the LDP peer is not a next hop for all FECs
If using Conservative retention, request labels for only those
FECs which u deem the LDP peer is the next hop.
This is the kind of filtering you would be talking about
The filter would in fact be the "match" of "LDP peer" for "FEC next hop"

chetan

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