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draft-ietf-mpls-in-ip-or-gre-01.txt to PS

  • From: Mark Duffy <mduffy@quarrytech.com>
  • Date: Tue, 12 Aug 2003 14:19:14 -0400
  • Cc: George Swallow <swallow@cisco.com>, Yakov Rekhter <yakov@juniper.net>, mpls@UU.NET

Hi Eric,

At 11:31 AM 8/12/2003 -0400, Eric Rosen wrote:
>On the  Tunnel MTU issue, you are  correct that the text  is confusing.  How
>about:
>
>         In some cases, the tunnel head receives, for
>         encapsulation, an IP packet, which it first encapsulates
>         in MPLS and then encapsulates in MPLS-in-IP or
>         MPLS-in-GRE.  If the source of the  IP packet is
>         reachable from the tunnel head, and if the result of this
>         encapsulation

I think "this encapsulation" above should be changed to read "the MPLS 
encapsulation" or the equivalent.  "this encapsulation" in this context 
seems to refer to both the MPLS *and* the MPLS-in-IP/GRE.  However, it is 
only the size of the IP packet plus the MPLS label stack that should be 
compared to the Tunnel MTU.

>would be a packet whose size exceeds the
>         Tunnel MTU, then the value which the tunnel head SHOULD
>         use for the purposes of fragmentation and PMTU discovery
>         outside the  tunnel is the Tunnel MTU value minus the
>         size of the MPLS  encapsulation.

Thanks, Mark