Re: udlr

[Patrick Cipiere <Patrick.Cipiere@ensim.com>]

> I would like to know in the satellite infrastructure what udlr implies 
> practically?

The goal of UDLR is to make a unidirectional network interface behave
as if it was bidirectional.
Assuming you have a receive only satellite card, you need also another 
bidirectional network interface card (a serial interface with a modem
and PPP works fine)
This second interface is used for the backchannel.

> Does it mean that you have to put a server in front of the 
> gateway

I think you call gateway the machine which holds the satellite network 
card (xmit side).
Depending of the openness of this gateway you might have the second
network interface in the gateway, or if the gateway is a blackbox, you
might have an IP gateway in front of the satellite gateway.

> and a software on each client receiving the satellite?

Yes, in our (INRIA) implementation you need a supplement for the
satellite interface driver and a daemon to encapsulate the level 2
datagrams in the backchannel.

> It's a level 2. What happens to the Ethernet packets? Is it
> encapsulated into a sort of UDLR packets and then forwarded to the
> the gateway.

Yes, level 2 datagrams are encapsulated in the backchannel using GRE.

Hope this will help,
Patrick.