[e2e] two questions about the Internet

[Hari Balakrishnan]

Erich,

> 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.  

For the 1996 Atlanta games, IBM actually ran multiple servers for the Olympics, 
but they weren't transparent (i.e., they had distinct DNS names).  The data 
being referred to here was collected at Southbury, CT.  The other sites were, 
if I recall, at Keio (Japan), Cornell (NY), Karlsruhe (Germany), and Hursley 
(UK).

The Southbury site was connected via T3 links to 4 US NAPs: Chicago (Bellcore & 
Ameritech), SF Bay Area (Bellcore and PacBell), NY (Sprint), and DC (MFS 
Datanet).

> 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.

Sounds about right, if you believe the load-balancing was working correctly.  
:}  (I'm not saying it wasn't!)

Hari

> 
> -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