Editors' note: These minutes have not been edited.
Montreal IETF Proceedings
Routing Area
UDLR BOF
Minutes of the UniDirectional Link Routing BOF session, Friday, June
28 (one session)
Reported by: Walid Dabbous, INRIA Sophia Antipolis
The goal of the meeting was to present and discuss the support of
unidirectional link in Internet routing protocols.
Walid Dabbous started by presenting the general problem: How to offer
a low-cost, high bandwidth connection to the Internet based on
broadcast satellite networks. As low-cost DVB hardware is receiver
only, the support of these satellite networks within the Internet
requires changes in common routing protocols.
Two access modes were described, namley the "basic access" mode
where each receiver has a satellite dish, and the "subnetwork access"
mode where the satellite dish is installed on a subnetwork router. The
subnet could be e.g. an ISP net receiving Mbone traffic on the satellite
link
The problem in the basic access mode is the dynamic mapping IP
addresses onto media addresses (on the unidirectional satellite
network). It was proposed to investigate the feasibility of a solution
based on the use of a static management table, and to compare it to a
solution based on a modification of ARP.
The problem in the subnet access mode is to support dynamic routing
even though it is not possible to receive routing update packets from the
receivers-only DVB hardware on the satellite subnetwork.
Two solutions for this problem were presented. The first one by
Emmanuel Duros from INRIA, in which he proposed modifications for
RIP, OSPF and DVMRP to support dynamic routing in the presence of
unidirectional links. The main idea is to allow routing udpates to be
sent to the sources sending on the satellite network (the feeds) via
regular Internet connections. Authentication is used to allow routing
updates packets received on an interface different from the one
concerned by them to be taken into account. The solutions are described
in detail in
ftp://zenon.inria.fr/rodeo/udlr/doc/draft-ietf-general-
udlr-00.txt
Another solution was presented by Yongguang Zhan from Hughes
Research Laboratories. This solution is based on the set up a tunnel to
the feeds and to send routing packets on it. This requires no changes to
the routing protocols, but may be harder to manage.
There were also a presentation made by Jun Murai from the WIDE
project, on WISH (Wide Internet With Harmonisation). In his
presentation, Jun described the Internet satellite based network
installed in Japan. No routing solutions were supported. Jun expressed
his interest in testing the proposed solutions on WISH.
Henry Sinnreich from MCI addressed the problem of link layers. He
said Ethernet like link layer are preferred (instead of MPEG2-like
transport). Harry Hakulinen from Nokia Research proposed to write an
internet draft proposal to explain how to encapsulate IP packets on top
of DVB transport.
Intersting questions, remarks and comments were raised and will be
discussed on the udlr mailing list
[email protected]. To subscribe
send e-mail to:
[email protected] Archive is at:
ftp://zenon.inria.fr/rodeo/udlr/archive.txt
The main decisions at the end of the BOF were to proceed both INRIA
and Hughes solutions in a coordinated way. These solutions are being
implemented and it is expected that INRIA experiment its solution on a
European scale (with the MERCI project partners) using DVB cards and
satellite capacity provided by Eutelsat.
Another BOF session in San Jose will be requested to present the resutls.
Decision on the possible start of a Working Group will be taken after
this second BOF session.
