The MPLS WG Archive

[George Swallow <swallow@cisco.com>]

Ping -

Totally agree that something along these lines is necessary.

Some comments:

The draft should say explicitly that the Echo and LSP-Ping messages
are sent down the LSPs.

If you have multiple LSPs between two nodes then it may be hard to
determine that an LSP has failed, since you will get Echo-Reply
messages from the other tunnels.  The draft should recommend use of
the Identifier field in the Echo message in this case.  

You don't give a message type for the LSP-ping.  Were you thinking of
a new message?  Perhaps the Notify message could be used?

There needs to be a means of clearing the LSP-echo object from the
RESV message.  (So that the test can be repeated at a later point).
I would simply add a timer that gets set when you first insert the
LSP-ping object in the RESV message and renewed each time you receive
a subsequent LSP-ping message.  Once the messages cease, the timer
will fire and you then send a RESV message without the LSP-ping
object.

You might add a note to the intermediate node processing that says
the text in only there to emphasize good practice.  It doen't really
impose any new requirements.

...George

==================================================================
George Swallow       Cisco Systems                   (978) 244-8143
                     250 Apollo Drive
                     Chelmsford, Ma 01824