Subject: RE: draft-gan-fast-reroute

From: [email-masked]
Date: Sat, 13 Oct 2001 12:13:37 +0200

Dave,

I agree on your reply. I want to add 1 more remark: The path MTU of the 
detour LSP reflects the MTU of the path [node 2 - node 4] while the path 
MTU of the main LSP is the MTU of the path [node 1, node 2, node 3, node 
4, egress] between node 1 and the egress node. If the detour takes over in 
node 2, I would expect the path MTU of the main LSP to reflect the MTU of 
the path [node 1, node 2, detour (node 2 - node 4), egress]. After all, 
one does want to avoid fragmentation in the middle of an LSP.

>>
>>        Node1 ====> Node2 ======> Node3 =====> Node4 ======> Egress
>>                       v                       ^
>>                       |                       |
>>                       +-----------------------+
>>

Best regards,

        Francis.

--------------------------------

To:
Sundara Murugan <[email-masked]>, "'Arthi Ayyangar '" 
<[email-masked]>, Francis ARTS/BE/ALCATEL@ALCATEL
cc:
"'Alia Atlas '" <[email-masked]>, "[email-masked] '" <[email-masked]>

Subject:
RE: draft-gan-fast-reroute

Sundara:

If the detour MTU must be >= the main LSP MTU, how is this achieved? If I
understand the protocol flows correctly, you only know what you got, you
cannot request a specific MTU. So there is not a method to easily find a
useful detour, and does this not disqualify perfectly good detour
opportunities when the RESV MTU for the main path exceeds the service
requirement?

thanks
Dave