Subject: draft-ietf-v6ops-mech-v2-06 and TTL when encapsulating

From: Pekka Savola <[email-masked]>
Date: Fri, 17 Sep 2004 14:37:57 +0300 (EEST)

Hi,

(co-chair hat on)

A couple of IESG people felt a bit unfortable with 
draft-ietf-v6ops-mech-v2-06.txt, the paragraph about which TTL to use 
when encapsulating (section 3.2).  Now it says:

   The TTL of the encapsulating IPv4 header is selected in an
   implementation dependent manner.  The current suggested value is
   published in the "Assigned Numbers" RFC [RFC3232][ASSIGNED].  The
   implementations MAY also consider using the value 255.
   Implementations MAY provide a mechanism to allow the administrator to
   configure the IPv4 TTL as the IP Tunnel MIB [RFC2667].

At least, they argued that the sentence about TTL=255 should be
removed.  One also argued that the whole paragraph is unnecessary,
because there should be nothing tunneling-specific here. (However,
there are a number of implementations which allow specifying the TTL
for just tunneling, so at least there are implementations..)

The TTL=255 suggestion is useful because it can be rather reliably be
used to figure out how many hops the particular tunnel packet has
traversed.

Do WG participants have opinions about this?

 1) (try to) convince the IESG to keep it as is
 2) remove the TTL=255 suggestion
 3) remove everything or almost everything
 4) rewrite the paragraph (suggestions are welcome)
 5) something else, what?

Off-list reply is also fine.

(hat off)

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings