In your previous mail you wrote:

   A router is supposed to send Time Exceeded ICMP when hoplimit goes to zero.
   
   However, it should not send this error, if the packet itself is an ICMP
   error, right?
   
   Now, in IPv6 I see a potential problem in implementing above. If there are
   unknown extension headers in front of the ICMP, as follows:
   
     IPv6 [ext. hdrs] ICMP6[Time Exceeded] ...
   
   If the router doesn't implement that particular extension header (for
   example AH, but also something totally new), how is it supposed to know that
   it should not generate a new ICMP Time Exceeded? (extension headers cannot
   be skipped without knowing them, as not all extension headers follow the
   same structure).
   
=> this was already discussed in this mailing list. The answer is to
send the Time Exceeded if it is too expensive (or impossible with ESP)
to know if the packet is an ICMP and to rely on ICMP rate limit in order
to keep some bandwidth for other traffic.

[EMAIL PROTECTED]
--------------------------------------------------------------------
IETF IPng Working Group Mailing List
IPng Home Page:                      http://playground.sun.com/ipng
FTP archive:                      ftp://playground.sun.com/pub/ipng
Direct all administrative requests to [EMAIL PROTECTED]
--------------------------------------------------------------------

Reply via email to