BoF on Unidirectional Link Routing

[Walid Dabbous <Walid.Dabbous@sophia.inria.fr>]

Hello,

I contacted Joel Halpern to ask for a BoF session on 
UniDirectionnal Link Routing during the next IETF in Montreal.
He advised me to ask you for the scheduling of this session.
A mailing list has been set up
udlr@sophia.inria.fr (for UniDirectional Link Routing). 
An announcement on the IETF mailing list will be done soon.

Regards,

Walid Dabbous


Here follows a proposed agenda and the problem description

-------------------------

Proposed agenda items: (to be completed)

Presentation of the problem 	Walid Dabbous, INRIA

Discussion of the proposed
solutions for RIP, OSPF, DVMRP  Emmanuel Duros, INRIA


-----------------------

The problem of Unidirectional link routing

Today, all the routing protocols assume that communication is
bidirectional between directly-connected routers. Links may be
asymmetric, e.g., have different delays and throughputs in different
directions, but they have to be duplex.

With the emergence of satellite networks, communication can be
unidirectional. Feeds transmit information to satellites which is
broadcast to a set of receivers. In that configuration, there is no
possibility for receivers to communicate with feeds since there is no
up-link.

In that particular configuration routing protocols are not
operational. Indeed, routers exchange protocol messages only with their
neighbors. A feed will never receive protocol messages from a receiver
since communication is unidirectional. For instance, a feed that uses
RIP (Routing Information Protocol), will never advertise routes via
satellite links because it never processes responses that come from
receivers. Therefore, IP datagrams will not be sent over the satellite
network.

Routing is based on the exchange of routing information to discover the
topology of the network. Feeds must in somehow get this information from
receivers. This might be feasible if feeds and receivers can also
communicate via regular connections. Receivers will send protocol
messages to the unicast address of each feed instead of sending
broadcast messages. 

This leads us to modify the code of every routing protocol in order to
handle unidirectional links.  We propose three drafts that presents the
modifications which can be applied to common routing protocols (RIP, OSPF,
DVMRP). These drafts can be obtained from:

ftp://zenon.inria.fr/rodeo/udlr/*.txt

For further information please contact
Walid.Dabbous@inria.fr
or
Emmanuel.Duros@inria.frWalid Dabbous


------------------------------

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