The MPLS WG Archive

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

>Hi,
>
>I've one question on LDP. What should be the behaviour of the LDP module
>when it receives the label mapping message for a FEC when the label
>retention mode is liberal and that FEC (e.g. partial IP prefix) is not
>visible to the local routing module? Should it store the label just 
>received
>or send out label release message?

"Should" store it


>Here, the routing module just doesn't
>have any information abt. this IP prefix. On querying, the routing module
>returns "route not available" or "no information abt. the route".
>
>As per the LDP specs., it's implicit/apparent that label distribution
>entities and routing entities should work in tandem and should remain in
>synch. So, what should be the behaviour in this special case where LDP sees
>some FEC but that FEC is not visible to routing entity?

Before the Routing information could be propagated,
the label mapping may be sent.
This may be 'cos of a timing difference between the
LDP and Routing entities [due to implementation behaviour].
The Routing entity may be able to send the routing information later
[say in a time frame of a few seconds after the label mapping message]

>
>The following from RFC 3036, doesn't talk abt. this case explicitly:
>LMp.12 Is MsgSource the Next Hop for FEC? If so, goto LMp.14.
>Should the boolean expression in the step mentioned above be considered
>"FALSE" in this specific scenario?
>Any response will be greatly appreciated.
>Thanks.
>Prem
>

chetan

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