[e2e] two questions about the Internet

[Erich Nahum]

George Michaelson writes:
> 
> The 96 Olympics were hosted behind multiple backends, geographically
> distributed? I thought Nagano was, I went to a seminar by IBM on it.
> 
> Because if so, there were presumably frontend boxes making decisions
> on backend server, which would either intuit best-fit path or else
> map it into some simple model like BGP AS or link-based region and
> so skew RTT in favour of shorter-hop and/or ligher-load hosts.

96 (Atlanta) was the first olympics that IBM hosted, and I believe it was
just one complex in Southbury, CT.  98 (Nagano) and 2000 (Australia)
were hosted by 4 main sites: Bethesda (for Europe), Shaumberg IL and 
someplace in Ohio (for the Americas) and Tokyo (for Asia).  The
request routing was done on a very course-grain level, basically
through the routing tables.  E.g., if you were in Europe,
olympics.com pointed to Bethesda. I think it was done at
the routing layer and not through DNS. 

The front ends of each cluster were IBM network dispatcher TCP
sprayers, which routed to back-end nodes on the same LAN.  So
I believe the RTT distribution seen by a complex would be the same
across nodes within that cluster.

-Erich

-- 
Erich M. Nahum                  IBM T.J. Watson Research Center
Networking Research             P.O. Box 704
nahum at watson.ibm.com            Yorktown Heights NY 10598