TCP Mapping

["Liu, Hong" <Hong.Liu@neustar.biz>]

Eric,

I would like to give a high level answer to your two questions. For details,
please see our draft coming up...

As you may have mentioned, there are two aspects of "EPP PUSH" (I am using
the term in a broad sense here):

First, the semantics of EPP PUSH, which is your second question. My
definition is the server pushing unsolicited data to the client during an
EPP session. By that, I mean a counterpart of <poll>. So conceptually, this
is very simple. Procedurally, it involves three steps:

o Negotiation of PUSH capability between the server and the client during
session establishment.
o Server-pushed message exchange after the session is setup as
"push-enabled".
o Session teardown post-processing (if required).

I have explained the first step in my previous email to you. The last step
may or may not be necessary, depending on whether we allow concurrent PUSH
over multiple sessions, and whether we allow changing session property on
the fly (e.g., from not push-enabled to push-enabled and vice versa). 

When I say "server" and "client", they are defined in the context of base
EPP and its TCP mapping. In the BEEP mapping, they may be better labeled as
peering receiver and sender. If they are to be defined in a transport
neutral manner, we may need to either redefine the two terms or come up with
new terms for them. I would prefer to keep them as defined in the base EPP,
but your suggestion is welcome.

Second, the syntax of EPP PUSH extension, which is your first questoin. This
is the topic I brought up to the list for discussion. The key question is
how to tag the server-pushed message. Using the "P"-bit in the Total Length
field is one way, defining a new <push> command and corresponding response
and some new result codes is another. Suppose we proceed with the second
approach. Then a new XML schema will define their syntax as extension,
referred to by an EPP PUSH URI. The <push> command at the minimum will carry
the data elements of a <poll> response. The EPP PUSH URI will also be used
in the session establishment step for the server to advertise this extension
and for the client to subscribe to the extension.

Of course, there are other details that need to be iron out. I hope that I
have answered your questions on a high level.

--Hong

-----Original Message-----
From: Eric Brunner-Williams in Portland Maine
[mailto:brunner@nic-naa.net]
Sent: Sunday, June 30, 2002 6:24 PM
To: Liu, Hong
Cc: 'ietf-provreg@cafax.se'; brunner@nic-naa.net
Subject: Re: TCP Mapping


Hong,

How is your extension supposed to work?

Exactly what do you mean by "EPP PUSH"?

Eric