2.4.10 Physical Topology MIB (ptopomib)

NOTE: This charter is a snapshot of the 42nd IETF Meeting in Chicago, Illinois. It may now be out-of-date. Last Modified: 14-Aug-98


Ken Jones <kjones@baynetworks.com>

Operations and Management Area Director(s):

Harald Alvestrand <Harald.Alvestrand@maxware.no>
Bert Wijnen <wijnen@vnet.ibm.com>

Operations and Management Area Advisor:

Harald Alvestrand <Harald.Alvestrand@maxware.no>

Mailing Lists:

General Discussion:ptopo@3com.com
To Subscribe: ptopo-request@3com.com
Archive: ftp ftp.3com.com (login: ptopo, passwd: ptopo)

Description of Working Group:

Document Editor: Gilbert Ho (Gilbert_Ho@3mail.3com.com)

The goals of this working group are:

o to agree on and document the common framework/model for discussing physical topology o to standardize a set of managed objects that provide physical topology information o to document media specific mechanisms to communicate topology information.

The managed objects should provide sufficient information to allow a management workstation to navigate across a set of agents in order to learn the topology of arbitrarily large networks, and these objects should be as independent as possible from the specific underlying networking media which comprise the network. These objects will be the minimum necessary to provide the ability to support the physical topology discovery, and will be consistent with the SNMP framework and existing SNMP standards.

In defining these objects, it is anticipated that the working group will leverage existing work for representing port-based information, such as in the Repeater MIB (RFC 1516 or later) and may also leverage work in the entity MIB for describing logical and physical relationships.

The working group will define the general requirements for topology mechanisms in order to support the proposed MIB. It will also identify existing topology mechanisms for common LAN media types and may propose new topology mechanisms for LAN media types where required. It is a goal of the common topology MIB to allow the use of either standard or proprietary topology mechanisms within the underlying media.

At this time, it is not a goal of the working group to support the collection or representation of logical topology information, such as VLAN configuration or subnet structure. It is anticipated that this could be an area for future work items, so some consideration will be given to extensibility of the models and to the MIB. However, this consideration must not be allowed to impede progress on the primary focus of physical connectivity.

Goals and Milestones:

Oct 96


Working Group formation approved by IESG Solicit input (proprietary MIBs, model)

Nov 96


Hold Interim meeting in San Jose

Nov 96


Post Internet-Draft for topology MIB

Nov 96


Post Internet-Draft for topology model

Dec 96


Working Group meeting at IETF-San Jose to review the initial IDs

Feb 97


Post revised Internet-Draft(s)

Mar 97


Review Internet-Draft(s) at IETF meeting

Jun 97


Submit final version of Internet-Draft(s) to IESG for consideration as a Proposed Standard


No Request For Comments

Current Meeting Report

IETF #42 WG Minutes
Chicago, IL August 25, 1998
WG Chair: Ken Jones (Ken_Jones@BayNetworks.com)
Minutes: Andy Bierman (abierman@cisco.com)

Review Material:
[1] Physical Topology MIB
[2] Physical Topology Discovery Protocol and MIB

1. Agenda Review
2. Discussion of IBM patent disclosure issues
3. WG Last Call discussion

Executive Summary:

The working group is almost finished with the two drafts in progress ([1] and [2]). A
"WG Last Call" was supposed to be issued on these drafts four months ago, but IBM
announced to the WG mailing list that IBM considered the PTOPO work to be in violation
of one of their patents. Since then, the WG has been trying to determine the best way to

1) Agenda Review

There were no changes made to the agenda.

2) Discussion of IBM patent disclosure issues

On April 29, 1998, John Tavs of IBM announced to the PTOPOMIB mailing list that
IBM believes the PTOPO work ([1] and [2]) to infringe on a Network Device Information
Exchange patent (U.S. patent #5276440). In accordance with IETF procedures, IBM has
announced its intent to enforce this patent, and its intent to license the "PTOPO
technology" in a non-discriminatory manner.

Harald Alvestrand presented some background material on the IETF's position on
encumbered technology, and explained the options open to the WG.

John Tavs presented the IBM position at the WG meeting.

The WG spent some time debating the merits of the IBM patent. Since none of the WG
members present were qualified attorneys, this discussion was not particularly useful, and
therefore none of these comments are documented in the minutes.

The WG was presented with 3 options, and an informal "straw-poll" was conducted.

1) Disband the WG

3 votes -- very few members felt the work should be terminated.

2) Publish the drafts with the disclaimers as specified in RFC 2026, section 10.3.2 and

12 votes; this option allows the WG to complete its charter quickly, and was the
most popular. The WG Chair conducted another straw-poll at this point:

3) Attempt to change the drafts so they do not conflict with the patent.

0 votes; WG doesn't know what (if anything) needs to be changed. IBM is not
willing to discuss possible changes to the PTOPO technology with the WG, so this
option was not seen as practical. Also, many WG members do not believe the
patent has merit, and do not wish to change the technology because of it.

4) WG Last Call discussion

The WG Chair is expected to issue a WG Last Call for both drafts, after they are re-published.


None received.

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