Re: [TE-wg] TE use in today's networks

[Jennifer Rexford <jrex@research.att.com>]

> I suspect that one of the papers referenced is:
>
>	http://infocom.ucsd.edu/papers/744.pdf

Two other papers (posted on the TE-WG list back in December 1999) include

  - A. Feldmann, A. Greenberg, C. Lund, N. Reingold, and J. Rexford,
    "NetScope: Traffic Engineering for IP Networks," IEEE Network 
    Magazine, March/April 2000.
      http://www.research.att.com/~jrex/papers/ieeenet00.ps

  - B. Fortz and M. Thorup, "Internet Traffic Engineering by
    Optimizing OSPF Weights," Proc. IEEE INFOCOM, March 2000.
      http://www.ieee-infocom.org/2000/papers/165.ps

> There are serious considerations to be overcome before this is
> practically implementable (ie, 10 significant digits on routing
> metrics).

The techniques in the papers listed above work with integer weights.
Experimental results seem to suggest that a small number of different
weight values are often sufficient in practice.

> Additionally, there are subsequent ops problems with implementing it
> (ie, dramatic impact when one link drops).

Depending on which link fails, the network load after the failure
isn't all that bad.  Although some failures can cause problems, often
one or two weight changes after the failure is enough to bring the
network back to a happy place (analogous to the need to fail over to
backup paths in MPLS).

> I suspect that this issue has been hammered to death on a mailing
> list somewhere, anone have pointers?

There has been some discussion recently on the IRTF-RR list...
Another reference listed there is

  http://www.eng.tau.ac.il/~shavitt/pub/DIMACS01-17.ps

-- Jen