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iplpdn-minutes-90dec.txt
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1993-02-17
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CURRENT_MEETING_REPORT_
Reported by George Clapp/Ameritech
IPLPDN Minutes
Opening Remarks
This was the first meeting of the IP over Large Public Data Networks
Working Group, and the meeting began with some introductory remarks
describing the reasons for the formation of the group.
SMDS is a new data service which may be tariffed by public carriers in
the United States beginning in 1991. A Working Group within the IETF,
IP over SMDS, has drafted a document specifying the operation of IP over
SMDS, in which they assumed that relatively small logical IP subnetworks
would be supported by SMDS. This document meets what is perceived to be
a near-term need for the industry. The group, however, felt that it
would be desirable to support public IP connectivity over SMDS, in which
any IP device may communicate directly with any other IP device attached
to the SMDS network. Three problems were identified which required
solutions before this goal could be reached:
1. A scheme to encapsulate IP datagrams and to identify the higher
layer protocol.
2. Routing in very large networks.
3. Address resolution in very large networks (mapping the protocol
address to the corresponding hardware address).
The concern with the latter two issues was that existing solutions to
routing and address resolution may generate excessive overhead when used
in very large networks. Bob Hinden and Noel Chiappa wished to form a
new Working Group to address these issues but felt that the problems
were common to all public data networks. Therefore, Frame Relay, ISDN,
and the work of the PDN Routing Working Group, which dealt with X.25
networks, were folded into this group as well.
Tasks and Work Done
Discussion of the anticipated usage of these different public data
networks led to a clarification of the tasks at hand and of the current
state of approaches to those tasks, as depicted below:
1
The figure depicts the three issues of encapsulation, address
resolution, and routing, and the environment in which a proposed
solution is to be used. ``Private'' denotes a Virtual Private Network
implemented over a Public Data Network (PDN); ``public'' denotes global
IP connectivity across a PDN. This graph was applied to the different
PDNs.
SMDS
Private Public
--------------------------------------
encapsulation | | |
& protocol | SMDS PDU, | SMDS PDU, |
identification | 802.2, & SNAP | 802.2, & SNAP |
| | |
--------------------------------------
| | |
address | ARP | ? |
resolution | | |
| | |
--------------------------------------
| | |
routing | existing | ? |
| solutions | |
| | |
--------------------------------------
Frame Relay
Private Public
--------------------------------------
encapsulation | | |
& protocol | ? | ? |
identification | | |
| | |
--------------------------------------
| | |
address | static | ? |
resolution | table | |
| | |
--------------------------------------
| | |
routing | existing | ? |
| solutions | |
| | |
--------------------------------------
X.25 Packet Switching
Private Public
--------------------------------------
encapsulation | | |
2
& protocol | RFC 877 | RFC 877 |
identification | | |
| | |
--------------------------------------
| | |
address | static | ? |
resolution | table | |
| | |
--------------------------------------
| | |
routing | existing | ? |
| solutions | |
| | |
--------------------------------------
ISDN Circuits
Private Public
--------------------------------------
encapsulation | | |
& protocol | ? | ? |
identification | | |
| | |
--------------------------------------
| | |
address | static | ? |
resolution | table | |
| | |
--------------------------------------
| | |
routing | existing | ? |
| solutions | |
| | |
--------------------------------------
Encapsulation and Higher Layer Protocol Identification
There is no commonly agreed upon scheme for the encapsulation of IP
datagrams and for the identification of higher layer protocols for frame
relay or for circuit ISDN. The group discussed the possibility of using
PPP or 802.2 LLC/SNAP for this purpose. There was some question whether
this work should be done within the IPLPDN Working Group or within a new
Working Group created expressly for this purpose. The opinion was
expressed that people interested in this topic are encouraged to
investigate the issues and to draft documents.
Routing and Address Resolution
3
A server model is a possible solution to the issues of scaling for
routing and address resolution. It was pointed out that the functions
of both address resolution and routing may be performed by a single
server, and that the server may respond to a routing query for an IP
address with the PDN address corresponding to that IP address, or to the
next hop for that IP address. Noel Chiappa pointed out that the current
approach uses a two step process:
1. Translate destination IP address to next hop IP address.
2. Translate next hop IP address to hardware (or PDN) address.
32 Bit CRC for IP Over SMDS
Rick Szmauz asked that the ``IP over SMDS'' document specify that the
optional 32 bit CRC of SMDS be used for all IP transmissions over SMDS.
He felt that the use of the CRC would more nearly meet the common
expectations of a MAC service. The group decided not to adopt this
change for both technical and procedural reasons. Technically, the
group felt that the 10 bit ``per cell CRC'' provided adequate error
control and, procedurally, it was felt that this issue should have been
discussed the previous day by the IP over SMDS Working Group.
Possible use of BGP as a Solution to Large Scale Routing
There was an extended discussion of the use of BGP (RFCs 1163 and 1164)
as a solution to the problem of large scale routing. The approach
appeared promising to those familiar with the routing protocol, and Paul
Tsuchiya, Russ Hobby, and George Clapp volunteered to draft something
before the next IETF meeting in March, 1991.
Attendees
Anne Ambler anne@spider.co.uk
Karl Auerbach karl@eng.sun.com
Terry Bradley tbradley@wellfleet.com
Caralyn Brown cbrown@ENR.Prime.com
Alan Bryenton
Duane Butler dmb@network.com
George Clapp meritec!clapp@uunet.uu.net
Tracy Cox tacox@sabre.bellcore.com
Caroline Cranfill rcc@bss.com
Avri Doria avri@clearpoint.com
Dino Farinacci dino@esd.3com.com
Peter Ford peter@lanl.gov
Vince Fresquez vince@druhi.att.com
Robert Gilligan gilligan@eng.sun.com
4
Juha Heinanen jh@funet.fi
Christine Hemrick cfh@thumper.bellcore.com
Robert Hinden hinden@bbn.com
Russell Hobby rdhobby@ucdavis.edu
Gary Kunis gkunis@cisco.com
Richard Libby libby@c10sd6.stpaul.ncr.com
Andrew Malis malis@bbn.com
Robert Meierhofer meierhofer@stpaul.ncr.com
Brad Parker brad@cayman.com
Yakov Rekhter yakov@ibm.com
Ray Samora rvs@proteon.com
Marc Sheldon ms@uni-dortmund.de
Daisy Shen daisy@ibm.com
Emil Sturniolo
Laszlo Szerenyi
Rick Szmauz szmauz@hifi.enet.dec.com
Sally Tarquinio sally@gateway@mitre.org
William Townsend townsend@xylogics.com
Paul Tsuchiya tsuchiya@thumper.bellcore.com
Gregory Vaudreuil gvaudre@nri.reston.va.us
Richard Woundy rwoundy@ibm.com
David Zimmerman dpz@dimacs.rutgers.edu
5