Subject: RE: WG next steps

From: "Tony Li" <[email-masked]>
Date: Sat, 16 Nov 2002 11:23:11 -0800

|   The end to end principle implies that each host should have
|   all the information and should receive IGP.

The end to end principle is that the network should not replicate
a function that has to be performed by the hosts.

How does this imply that the host should participate in routing?

In fact, an argument for loose coupling suggests that the host
should do as little routing as possible.

Tony

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From: Masataka Ohta <[email-masked]>
Date: Sun, 17 Nov 2002 04:37:57 +0859 ()

Tony Li;

> a function that has to be performed by the hosts.

Wrong.

> How does this imply that the host should participate in routing?

From rfc1958:

   To quote from [Saltzer], "The function in question can completely and
   correctly be implemented only with the knowledge and help of the
   application standing at the endpoints of the communication system.
   Therefore, providing that questioned function as a feature of the
   communication system itself is not possible. (Sometimes an incomplete
   version of the function provided by the communication system may be
   useful as a performance enhancement.")

> should do as little routing as possible.

There is no such argument.

							Masataka Ohta

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From: Eliot Lear <[email-masked]>
Date: Sat, 16 Nov 2002 13:19:07 -0800

Reading further down that very same RFC 1958:

                             vvvvvvvvvvv
    To perform its services, the network maintains some state
                             ^^^^^^^^^^^
    information: routes, QoS guarantees that it makes, session
    information where that is used in header compression, compression
    histories for data compression, and the like. This state must be
    self-healing; adaptive procedures or protocols must exist to derive
    and maintain that state, and change it when the topology or activity
    of the network changes.

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From: Masataka Ohta <[email-masked]>
Date: Sun, 17 Nov 2002 09:00:32 +0859 ()

Eliot;

>     To perform its services, the network maintains some state

So? Did someone forbid the network perform routing?

						Masataka Ohta

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From: Iljitsch van Beijnum <[email-masked]>
Date: Sun, 17 Nov 2002 20:30:25 +0100 (CET)

> How does this imply that the host should participate in routing?

Isn't that obvious? If we can make the end-hosts do routing, the e2e
principle dictates routers should no longer do this.

You could pervert this logic into the position that IP should do away
with hop-by-hop routing and do source routing instead.

:-)

Iljitsch