2.3.4 Internetworking Over NBMA (ion)

NOTE: This charter is a snapshot of the 41st IETF Meeting in Los Angeles, California. It may now be out-of-date. Last Modified: 27-Mar-98


Andy Malis <malis@ascend.com>
George Swallow <swallow@cisco.com>

Internet Area Director(s):

Jeffrey Burgan <burgan@home.net>
Thomas Narten <narten@raleigh.ibm.com>

Internet Area Advisor:

Jeffrey Burgan <burgan@home.net>

Mailing Lists:

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Description of Working Group:

Note: This Working Group is jointly chartered by the Routing Area. The Routing Area Director: Joel Halpern (jhalpern@newbridge.com)


The Internetworking Over NBMA Working Group was formed to combine the work of two previous working groups, IP Over ATM (ipatm) and Routing Over Large Clouds (rolc), because these two groups were often working very closely together on similar, if not identical, problems and solutions. The group will be evolutionary, not revolutionary; it will continue the work in the previous groups on the NBMA Next Hop Resolution Protocol (NHRP), IPv4 over ATM, and IPv6 over ATM.


This WG will focus on the issues involved in internetworking network layer protocols over NBMA (non-broadcast multiple access) subnetwork technologies, such as ATM, Frame Relay, SMDS, and X.25 private and public networks. The group will endeavor to make all its solutions applicable to the entire range of network layer protocols and NBMA subnetworks. We recognize, however, that there will be cases where specific optimizations to IPv4, IPv6, and particular subnetwork technologies will result in better service to the user.

The group will focus on protocols for encapsulation, multicasting, addressing, address resolution and neighbor discovery, interactions with and optimization of internetworking-layer routing protocols when run over NBMA subnetworks, and protocol-specific network management support, as appropriate. The working group will submit these protocols for standardization.

The working group may also produce experimental and informational documents, including "Best Current Practices" guidelines, as required.

For ATM, the WG will continue the ipatm WG's transition from the LIS model described in RFC 1577 to the generalized NHRP model developed by the rolc WG, including a transition plan for existing networks.

The working group will coordinate its activities with the following other working groups:

1) Integrated Services over Specific Lower Layers (issll), for coordinating Quality of Service (QoS) issues and the implementation of IP integrated services capabilities (RSVP, the service models, etc.) over NBMA networks.

2) IP Next Generation (ipng), for IPv6 over ATM coordination.

The working group will also coordinate its work with other relevant standards bodies (e.g., ATM Forum, Frame Relay Forum, ANSI T1S1, ITU-T) and make recommendations to these organizations regarding the requirements for IP internetworking where the current published subnetwork standards, practices, or functionality do not meet the needs of internetworking.

The working group will not develop subnetwork layer standards.

Goals and Milestones:



Begin work on internetworking over Frame Relay SVCs (RFC 1490 extension), using NHRP for address resolution.



Revise drafts on NHRP, 1577 revisions, server synchronization (applicable to both NHRP and ATMARP), multicast server and broadcast for ATM, IPv6 neighbor discovery, ATM UNI 4.0 signaling (RFC 1755 update), Classical IP and NHRP MIBs, NHRP applicability, ATMARP to NHRP transition plan, and router-router NHRP.



IAB and IESG review of WG Status, and plans. This meeting will be scheduled to occur during SIGCOMM '96.



Submit NHRP, RFC 1577 revisions, and server synchronization to the IESG as a Proposed Standard, complete the ATMARP to NHRP transition plan and NHRP applicability statement, revise drafts on multicast server and broadcast for ATM, IPv6 neighbor discovery, classical IP and NHRP MIBs, router-router NHRP, ATM UNI 4.0 signaling (RFC 1755 upd



Submit IPv6 neighbor discovery, classical IP and NHRP MIBs, router-router NHRP, ATM UNI 4.0 signaling (RFC 1755 update), multicast server and broadcast for ATM, and NHRP for Frame Relay SVCs to the IESG.



Publish the IP over ATM Framework document (now RFC 1932), submit the MARS draft to IESG as a Proposed Standard.

Jan 98


Update for RFC1490 (to be submitted as Standard)

Jan 98


Update for RFC1293 (to be submitted as Draft Standard)

Feb 98


Submit IPv6 over NBMA, ATM, and FR drafts to IESG for consideration as a Proposed Standard.

Feb 98


Submit Distributed MARS Service Using SCSP to IESG for consideration as an Informational RFC.

Feb 98


Submit NHRP MIB to IESG for consideration as a Proposed Standard.

Mar 98


Submit ILMI-Based Server Discovery for ATMARP to IESG for consideration as a Proposed Standard.

Mar 98


Submit ILMI-Based Server Discovery for MARS to IESG for consideration as a Proposed Standard.

Mar 98


Submit Intra-area Unicast based upon OSPF ARA to IESG for consideration as a Proposed Standard.

Mar 98


Submit ILMI-Based Server Discovery for NHRP to IESG for consideration as a Proposed Standard.

Mar 98


Submit Ion Security I-D to IESG for consideration as a Proposed Standard.

Nov 98


NHRP client guidelines

Nov 98


Use of Proxy PAR

Nov 98


Router-Router NHRP

Dec 98




Request For Comments:







Issues affecting MARS Cluster Size



Multicast Server Architectures for MARS-based ATM multicasting.



Management Information Base for Frame Relay DTEs Using SMIv2



IP Broadcast over ATM Networks



Using the MARS model in non-ATM NBMA networks.

Current Meeting Report

Minutes of the Internetworking Over NBMA (ion) Working Group

The ION working group met in one session on Monday 30 March 1998, from 13:00 û 15:00, and was chaired by Andy Malis <malis@ascend.com> and George Swallow <swallow@cisco.com>. Andy Malis took the minutes.

Andy presented the introductory overheads. Joel Halpern stated that he is going be obtain the source to the router-to-router NHRP draft and produce an update. Cliff Wang is in the process of updating the SCSI MIB, and welcomes additional co-authors. Updates to the charter workplan are April 1998 for the IPv6 set of drafts, April 1998 for the NHRP MIB, May 1998 for ILMI-based server discovery, and August 1998 for SCSP for ATMARP.

Kenichi Kitami, the Study Group 11 chair in the ITU, presented "Expected Directions for Broadband and Multimedia Signaling", especially with respect to signaling additions to assist IP over ATM applications. Several proposed additions to ITU signaling include new Generic Identifier Transport and User-User Information Elements. Applications would include transfer of Internet-related information during session establishment. Two examples are QoS information for the IP layer and a VC identifier for MPLS.

Muneyoshi Suzuki presented "Assignment of the Information Field and Protocol Identifier in the Q.2941 Generic Identifier and Q.2957 User-to-user Signaling for the Internet Protocol", which was a continuation of work he first presented at the Washington meeting. He presented the changes in draft-suzuki-git-uus-assignment-02.txt and discussed the open issues. This draft is also going to be presented to the MPLS WG.

Joan Cucchiara presented the current status of the NHRP MIB, draft-ietf-ion-nhrp-mib-03.txt. She presented an overview of the MIBÆs groups and tables. There are three groups, the general group, the nhc group, which needs to be supported in the client, and nhs group, for servers.

There are two open issues she would like feedback for on the list:

1. There was a request on the list to add MPOA-specific information to the MIB. She feels that this is a duplication of the MPOA MIB, and would prefer not to add it.
2. Adding a nhrpClientNexHopResTable object for debugging û it would hold an error return code. However, this is very transient information, and she doesnÆt plan it at this time.

The following work is still outstanding:

Please provide feedback and comments on the list. She plans one more revision of the MIB, followed by last call in April.

Felix Wu presented his and Cliff WangÆs SCSP Security Analysis, draft-wang-ion-sec-scsp-00.txt. Felix discussed security concerns about the current draft, based upon their work on OSPF security analysis. He gave a quick SCSP overview, and showed examples of possible attacks against SCSP. SCSP already has a security mechanism that uses hop-by-hop authentication, but Felix described an attack from an insider that had access to a trusted SCSP entity. Other possible attacks include attempted denial of service.

OSPF already has the ability to digitally sign link state advertisements, and this same sort of mechanism could be used for SCSP, by digitally signing the cache state updates. However, this could lead to additional denial of service attacks because of the performance hit that comes from the use of public key cryptography. Their suggestion is to detect problems after they occur rather than try to prevent them (intrusion detection). They recommend that SCSP enhance the detectability and robustness of the protocol. There was some amount of contention between whether an implementation should try to fight back, because this could create a lot of traffic on the network and itself become a denial of service attack. Jim Luciani suggested instead notifying the NMS that there was a problem occurring. There was no consensus in the meeting for adding additional security mechanisms to SCSP at this time.

Peter Schulter spoke on the current status of the Ipv6 drafts, draft-ietf-ion-ipv6-01.txt and draft-ietf-ion-ipv6-atm-01.txt. Peter gave an overview of the current contents of the drafts. There is still one open issue with the baseline specification û a new option number is required from the ipng working group. Once the option number is assigned, the baseline document will be ready for last call. There was a typo regarding the IP MTU in the ATM draft, and this will be corrected. Once that is done, it will also be ready for last call. The updates are expected soon.

Jim Luciani presented NHRP with mobile NHCs, draft-luciani-ion-nhrp-mobile-nhc-00.txt. This goes back to work that was originally proposed over two years ago. While some provisions were made in the current NHRP specification for mobility, the current security mechanism does not promote mobility, since it requires a pairwise trust relationship between the NHC and a large number of potential NHSes.

JimÆs suggested modification is to add a new TLV for registration and purges. It will have end-to-end semantics between the NHC and the serving NHS. This will allow the NHC to register with its home NHS in a secure manner. The NHC only needs a trust relationship with its home NHS, and not the other NHSes that relay its registration and purge requests. He asked that it be sent out for WG last call.


Assignment of the Information Field and Protocol Identifier
Expected Direction for Broadband and Multimedia Signaling
Security Analysis to Server Cache Synchronization
ION - Agenda

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