North American Network Operators Group

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IPv4HT - Re: Usage of IPv6 flow label

  • Date: Tue Nov 21 12:54:23 2000

Thank you for your comment. In my opinion, there is a difference between a
"service" and a bunch of routers,
which may be in service or not. If the NANOG people want to focus on the
"service" of having an end-to-end
network with SIMPLE IPv4 (i.e. TOS not changed in transit)**, then they
should be able to point out to people
which companies (deploying the service, not building routers), abide by the
policy of allowing a user to insert
any 8 bit value into the IPv4 TOS field, and have that same value emerge on
the other side of the cloud that
NANOG claims to collectively "operate".

Furthermore, I would think that companies engaged in deploying the "service"
would want to make sure they
point out to their customers that they provide, true, end-to-end, IPv4 IP
Header Transport [IPv4HT].
(let's leave TCP and UDP out of this). I would also think that companies NOT
providing this service would
realize that there may be no motivation for those companies that do provide
the service to deal with the
headaches that non-conforming companies create. In short, they should stop
routing to them. Also, I would
think that the sales people from companies that DO provide IPv4HT, would
want to point out to the current
customers of those companies who do not, that they are using a NotWork, as
opposed to a NetWork.
As a service to the community, NANOG can easily run some tests to see which
companies provide IP4HT
and which do not. I have been personally surprised that some large
companies, do not even know what their
global policy is.

As an aside, one could consider other fields of data communications, and
consider what would happen if
people walked up after the fact and "re-wrote the rules". Most people are
probably familiar with 8-bit PCM
voice streams, imagine an end-to-end "service" where for years people were
able to get a clear-channel
8-bit PCM stream. Imagine, that everything worked fine, they place a 5 in
one end and a 5 comes out the
other end, they place the next sample, a 67 in one end and a 67 comes out
the other. Now, imagine some
equipment that comes along and randomly changes the 5 to a 6 or a 4, and the
67 to a 68 or a 66. Imagine
what would happen if people had built software assuming a 5 in one end comes
out a 5 at the other, not a 6
or a 4. Don't you think that network operators would come together and
collectively realize that they have
a major mess on their hands if they continue to change the values of the
data stream that the CUSTOMER
was told will be delivered, end-to-end, with a best effort, and not be
changed from what the customer
supplied ?

There are not really that many bits in an IPv4 header. In my opinion,
companies should FIRST focus on
making sure they have a global cloud that can reliably transport the bits in
the IPv4 header from "end-to-end".
I think it is up to technologists to make sure that sales people know that
they need to inform their customers
that they provide IPv4HT, and if that differentiates them from another
company that changes the customer's
bits in transit, then so be it. At some point, it seems to me that we should
be able to identify a collection of
vendors who provide IPv4HT. For people that want IPv4HT service, I can not
imagine why they would not
want to use those vendors. Why by a "service" from companies who do not
provide the service ?

**  [Yes, folks...I know TTL and checksum change, please do not send me
private mail describing
your recent "ta-da" revelation, that those fields "change".]

Jim Fleming

----- Original Message -----
From: Thomas Eklund <[email protected]>
To: 'JIM FLEMING' <[email protected]>; 'Jim Bound' <[email protected]>;
'Alex Conta' <[email protected]>
Cc: 'Steve Deering' <[email protected]>; 'Michael Thomas' <[email protected]>;
'Francis Dupont' <[email protected]>; 'Jun-ichiro itojun
Hagino' <[email protected]>; 'Hesham Soliman (EPA)'
<[email protected]>; 'Metzler Jochen'
<[email protected]>; 'Ipng (E-Mail)' <[email protected]>;
<[email protected]>
Sent: Tuesday, November 21, 2000 10:27 AM
Subject: RE: Usage of IPv6 flow label

> > In my opinion, the IPv4 TOS should also be "e-2-e"...
> > ...clients should set it....routers should leave it alone....
> IPv4 ToS or IPv6 Traffic Class field is 8 bits and today most routers use
> bits for them for diffserv (DSCP) and then it is per defintion PER hop
> behaviour and having possibility to re-write it at ingrees/egress router
> your domain
> ..
> -- thomas
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