[16NG] Re: Last Call: draft-ietf-16ng-ipv6-over-ipv6cs (IPv6 Over the IP Specific part of the Packet Convergence sublayer in 802.16 Networks) to Proposed Standard

Hi James,

Response inline:

On 3/14/07 11:14 AM, "ext James Carlson" <james.d.carlson@sun.com> wrote:

> Basavaraj Patil writes:
>> A slightly revised version of the I-D is now available at:
>> http://people.nokia.net/~patil/IDs/draft-ietf-16ng-ipv6-over-ipv6cs-09.txt
> 
> I've read through the document as well as (most of) the mailing list
> discussion, and I don't see anything that directly addresses one
> possible issue here.
> 
> That issue is the exclusive use of IPv4 or IPv6 on Packet CS.  Why
> must it be exclusive?  The first four bits of the datagram tell you
> conclusively whether you're looking at IPv4 or IPv6, so why is strict
> segregation needed?

Not sure I understand what you mean by segregation... The same packet CS is
used for IPv4 as well as IPv6. There are no separate CS' per se.
The classification rules segregate an IPv4 packet from an IPv6 packet and
map it to the appropriate transport connection (CID) over the air interface.

> 
> Can't both run on the same link?

I guess you mean both IPv4 and IPv6 packets on the same transport connection
(CID), right? Why would you want to do that even if you could? It is cleaner
to setup separate transport connections and use specific classifiers for
each of these which gives you more control over the type of QoS or bearer
for each. But to answer your question more specifically:
No. When the transport connection is established there is a parameter which
specifies the CS that the connection will use and it is specified in Sec
11.13.19.1 of IEEE P802.16-REVd/D5-2004. The options in the table indicate
that the connection will support only IPv4 (1) or IPv6 (2) etc.

> 
> (I'm also a bit concerned that this proposal will end up rediscovering
> RFC 1547 over time, as other unnegotiated point-to-point mechanisms
> have in the past, and the reasons why PPP's negotiation exists.  I'm
> certainly not arguing for the use of PPP over Ethernet CS -- that'd be
> worse still -- but I think the IEEE may have made a mistake in
> defining an IP Packet CS rather than a PPP Packet CS.)

IEEE is specifying what is called as GPCS (generic packet CS) and I think
that some of these will be addressed therein.

-Raj

>-- 
>James Carlson, Solaris Networking              <james.d.carlson@sun.com>
>Sun Microsystems / 1 Network Drive         71.232W   Vox +1 781 442 2084
>MS UBUR02-212 / Burlington MA 01803-2757   42.496N   Fax +1 781 442 1677

_______________________________________________
16NG mailing list
16NG@ietf.org
https://www1.ietf.org/mailman/listinfo/16ng