Re: DVB & all (Re: ipsat BoF)

[Joel Halpern <jhalpern@ca.newbridge.com>]

TCP Relay and related issues fall into the TCP Sat working group, where
there are many debates on the right way to do this.  (My personal
prejudices run end-to-end, but there are alteratives such as relays,
spoofs, etc.)

As for the routing mechanism, I believe that the current UDLR mechanisms
would give the best approximation consistent with internet routing
philsophy.  The downstreams would have UDLR tunnels back to each of the
transmitters, and would exchange routing with each of them.  The routing
system would select the shortest path to the destination.  No, this does
not let the receiver select which satellite transmitter is used.  Just as
normal routing does not let the receiver choose which router is used to
reach it.  Those are routing issues.  Adjust the metrics to reflect the
polcies.  Use BGP to deliver explicit policy.

On Tue, 4 Aug 1998, nghia PHAM wrote: (in response to a note from me)

> We have the following satellite topology with our Skyplex onboard
> multiplexing:
> A number of udl feeds transmit their packets to
> the same satellite transponder which, with onboard processing,
> concentrates the uplink streams into a single downlink stream.
> 
> I would like to see a routing mechanism which allows a udl receiver to
> specify a
> route so that the last hop to it must transit through any of a given 
> set of udl feeds (dynamically detected by the receiver). The selected 
> udl feed should preferably result in the best throughput, 
> heuristically, the closest to the server being queried. 
> 
> I would like also to know whether it makes sense to have, assuming
> the udl receiver is the end point of a TCP connection, a kind 
> of TCP relay whereby on the satellite hop the TCP parameters may be 
> different (e.g. larger window, no slow start...) from that the of the path
> from the server to the udl feed.
> 
> I do not know whether this is complex or trivial but if there is a BoF 
> in Chicago as requested by Walid, I can make a presentation
> of our Skyplex system.
> 
> Regards,
> 
> Nghia PHAM      npham@eutelsat.fr , nghia_pham@compuserve.com
> Digital Systems Division
> EUTELSAT - European Telecommunication Satellites Organisation
> (www.eutelsat.org) 
> 

Yours,
Joel M. Halpern                         jhalpern@newbridge.com
Newbridge Networks Inc.