Subject: iTTL determination with Ethernet frames

From: [email-masked]
Date: Mon, 09 Dec 2002 11:27:33 +0100

Hi everyone,
I have the following question about Time to Live (TTL) Processing in 
MPLS Networks (Updates RFC 3032) draft.
The draft describes the TTL processing with incoming IP/MPLS packets.
Consider the following scenario.
The incoming flows are Ethernet TLS flow traversing an intervening MPLS 
network. The typical scenario is to assign each flow, entering and 
leaving the MPLS network from the same end points, with a VC label 
(following Martini's draft) and encapsulate all the obtained VC tunnels 
into a single tunnel LSP, in order to offer all the clients the same 
service. That is, on each incoming Ethernet frame will be pushed a stack 
of two label.

In this case, what should the iTTL be, since it cannot be inferred 
neither from an IP header nor from a MPLS header?

Wouldn't it be a good idea to extend the content of the draft to the 
case of transport of layer 2 frames over MPLS as well?

Thanks for spending your valuable time.
Regards Roberto