RE: WG last call: draft-ietf-tewg-diff-te-reqts-04.txt

["Sudhakar Ganti" <sganti@tropicnetworks.com>]

Jerry,

Answers in line ..

-Sudhakar

> > 1) How would an LER use the knowledge of BC model in
> >    the path setup/compassion?
> 
> As one example (there are lots I believe), the LER might use the BC 
> model in conjunction with the LSDB/TED to do constraint based routing 
> of an LSP.

The LSDB/TED has available bandwidth information for a TE Class. 
Let us say that there is enough bandwidth available for the TE-Class 
and the LSP maps to that TE-Class. But the links use different 
BC model. Do you reject the LSP setup because the models 
are different, though bandwidth is available?

> > 4) What is the impact of different models in a network?
> 
> I suppose it depends on how different the models are.
> For example, if each link in a network has 100 units of bandwidth,
> and:
> - half the links have 1 unit of bandwidth allocated to CT1, 99 units
> to CT2;
> - other half of the links have 99 units of bandwidth
> allocated to CT1, 1 unit to CT2; That's pretty incoherent.  
> Perhaps you can create an example to show how it is 
> beneficial to use different BC models on the links.
> 

In this example say BC0 = CT1 and BC1 = CT2. Then this
example assigns different values for the same BC, that
is a local policy and cannot be checked by the DS-TE
solution. My example is on first link BC0 = 20; BC1 = 
80 (complete partitioning of link bandwidth among two 
traffc types, i.e, BC0 is for CT1 and BC1 is for CT2). 
Second link has BC0=20; BC1=100 (sharing, i.e, BC0 = CT1 and 
BC1 = CT1+CT2). It works perfectly fine as long the TE-Class 
available bandwidth is computed correctly.

-Sudhakar