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Minutes of the BOF
Here follows the minutes of the Bof session.
You comments are welcome/encouraged!
I'll send more detailed questions that were raised during
the BoF session for discussion in a subsequent mail.
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 udlr@sophia.inria.fr.
To subscribe send e-mail to: udlr-request@sophia.inria.fr
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.
Walid Dabbous
INRIA U.R. de Sophia Antipolis | Email : dabbous@sophia.inria.fr
2004, Route des Lucioles BP 93 | Phone : +33 93 65 77 18
06902 Sophia Antipolis CEDEX France | Fax : +33 93 65 77 65