The Routing Over Large Clouds Mailing List Archive by date

[salo@msc.edu (Tim Salo)]

> To: salo@msc.edu (Tim Salo)
> Subject: Re: NHRP/MARS version number location. 
> Cc: rolc@nexen.com, ip-atm@matmos.hpl.hp.com, gja@thumper.bellcore.com
> Date: Thu, 28 Dec 1995 23:40:13 -0500
> From: James Luciani <luciani@nexen.com>
> 	[...]
> > However, as you show below, the MARS header doesn't really have a
> > version number...
> 
> What is ar$op.version then? 
> 	[...]

As you say below, it identifies a protocol, not a version of a protocol.

Note that I assert that my use of the term "version" is consistent with
the use of the term in other Internet protocols.  Specifically, 
"version," as it appears to be used in other IETF protocols, indicates
a variant of a protocol that performs roughly the same function as the
previous version of the protocol and that version n+1 is expected to
replace version n.

I don't believe that NHRP and MARS are versions in the sense that one
in intended to replace the other.

(Do we need to solicit opinions from the broader IETF community about
the appropriate definition of the term "version?")

> > So, it appears that what you have been calling a "version" number is
> > really a protocol identifier.  In other words, there is no protocol
> > version number within the MARS header, only a [mislabeled] field which
> > indicates the protocol.
> 
> Again, you missed the point of the harmonization of the NHRP and MARS.
> The version number identifies the instance of the address resolution
> protocol.

It sounds like you just affirmed my assertion that the MARS "version"
number is actually a protocol identifier.

As I mentioned earlier, you might find it instructive to examine the
use of the version field other Internet protocols.

Note that my recommendation that a protocol ID and protocol version
number be placed early in the packet is independent of any
discussion of harmonization.

On the other hand, I believe that NHRP and MARS should be be allowed to
evolve independently.  It appears that the evolution of NRHP and MARS
will be driven by different factors: perhaps NHRP by a better understanding
of short-cut routing and MARS by changes in the functionality of
ATM switches and UNI versions.

Do you believe that harmonization will allow NHRP and MARS to evolve
independently?

-tjs