semantics ambiguity with interas-in/out: clarification sought

 cengiz at ISI.EDU (Cengiz Alaettinoglu) writes:
  * 
  * as-in: AS1 pref1 polexpr1
  * interas-in: AS1 lid rid pref2 polexpr2
  * 
  * with the above description, the routes imported through (rid, lid)
  * connection is:
  * 	polexpr1 or polexpr2
  * with the following preferences:
  * 	pref2 polexpr2
  * 	pref1 (polexpr1 setminus polexpr2)
  * 
  * Is this right? (If it is, including above more formal formulation
  * might help more implementors).
  * 
Nope 0 there is no relation between the prefs. Also as-in must describe the
set of al interas-ins.

  * Eg.
  * as-in: AS1 100 AS2 AS3 AS4
  * interas-in: AS1 lid rid 90 AS2 AS4 AS5
  * 
  * that is import routes in
  * 	AS2 AS3 AS4 AS5
  * with the following preferences
  * 	90 AS2 AS4 AS5
  * 	100 AS3
  * 
  * Is this right?
  * 
See above - there is no relation between the cost in as-in and the pref in
interas-in. 
  * More complicated E.g.
  * as-in: AS1 100 AS2 AS3 AS4
  * interas-in: AS1 lid rid 90 (AS2 AS4 AS5) AND NOT AS3
  * 
  * Note that "(AS2 AS4 AS5) AND NOT AS3" is equivalent to "AS2 AS4 AS5".
  * Hence this example is identical to previous one and there is no way to
  * avoid importing routes in AS3.
  * 
  * Actually with the current definitions there is no way that the local
  * policies can be a restricted version (subset) of global
  * policies. (Unless the global policy is "NOT ANY" and everything is
  * done through local policies. Of course, this is not intended.)
  * 
  * Is this right?
  * 
Nope  as the original assumption is not right. Why not check the text 
in the light of changes  I made in the final draft just released. Hopefully,
this is a little clearer than before.

	--Tony.



-------- Logged at  Sun Sep 18 18:47:23 MET DST 1994  ---------