distance vector algorithms

[Tony Li <[e-mail]>]

Hi Martha,

   Using path vector algorithms for policy-based routing and applying
   route selection criteria based on source and transit policies means
   that gateways executing these algorithms do not necessarily accept the
   most recent routes that they learn about.  They judge each route
   according to its consistency with their policies.  That is exactly as
   it should be.  However, such route selection also means the possibility
   of the type of looping I described in the previous messages.  Hence,
   path vector algorithms for policy-based routing should have increased
   loop detection capabilities, to reduce the probabilities of such loops.
   Even so, I do not believe that these algorithms can ever eliminate this
   type of looping problem.

The mechanism that I described in my previous message completely
eliminates looping problems.  It is not an addition, but is already
present in BGP.

Tony