Subject: [BEHAVE] Comments on draft-ietf-behave-v6v4-xlate-05 (review)

From: Kentaro Ebisawa <[email-masked]>
Date: Thu, 31 Dec 2009 05:30:26 +0900

Hi Xing,

Other than the items still discussed in the ML, I have 4 more comments
on the draft-ietf-behave-v6v4-xlate-05.

1. [Page 14]  2.5.  Translator sending ICMP error message
>    If the packet is discarded, then the translator SHOULD be able to
>    send back an ICMP message to the original sender of the packet,
>    unless the discarded packet is itself an ICMP message.  The ICMP
>    message, if sent, has a type of 3 (Destination Unreachable) and a
>    code of 13 (Communication Administratively Prohibited).  The
>    translator device MUST allow to configure whether the ICMP error
>    messages are sent, rate-limited or not sent.

There are some cases which translator drops packet and send ICMPv4 packet
other than Type 3, Code 13 like when doing part of path MTU discovery.
So we should mention "unless otherwise specified in this document or
[I-D.ietf-behave-v6v4-xlate-stateful]" like below :

...
    message, if sent, has a type of 3 (Destination Unreachable) and a
    code of 13 (Communication Administratively Prohibited) unless
    otherwise specified in this document or in [I-D.ietf-behave-v6v4-xlate-stateful].
...

2. [Page 19]  3.2.  Translating ICMPv6 Headers into ICMPv4 Headers
>    ICMPv6 error messages:
> 
>       Destination Unreachable (Type 1)  Set the Type field to 3.
>          Translate the code field as follows:
...
>          Code 4 (port unreachable):  Set Code to 3 (port unreachable).

I think we should add below (code 5, 6 should be droped) :

            Other Code values:  Silently drop

>       Packet Too Big (Type 2)  Translate to an ICMPv4 Destination
>          Unreachable with code 4.  The MTU field needs to be adjusted

Add Type for clarification.

       Packet Too Big (Type 2)  Translate to an ICMPv4 Destination
           Unreachable (Type 3) with code 4.  The MTU field needs to be adjusted

3. [Page 21]  3.4.  Translator sending ICMPv6 error message
>    If the packet is discarded, then the translator SHOULD be able to
>    send back an ICMPv6 message to the original sender of the packet,
>    unless the discarded packet is itself an ICMPv6 message.  The ICMPv6
>    message, if sent, has a type of 1 (Destination Unreachable) and a
>    code of 1 (Communication with destination administratively
>    prohibited).  The translator device MUST allow configuring whether
>    the ICMPv6 error messages are sent, rate-limited or not sent.

As discussed in "[Page 14]  2.5.  Translator sending ICMP error message",
we should mention "unless otherwise specified in this doecument or
[I-D.ietf-behave-v6v4-xlate-stateful]" like below :

...
    message, if sent, has a type of 1 (Destination Unreachable) and a
    code of 1 (Communication with destination administratively
    prohibited) unless otherwise specified in this doecument or
    [I-D.ietf-behave-v6v4-xlate-stateful].
...

4. [Page 23]   7.  Appendix A: Translating pointer in Parameter Problem

We need to modify this based on the feedback during the WGLC.
(Noted just as a reminder)

Regards,
-- 
Kentaro Ebisawa <[email-masked]>