Subject: Guaranteed Delay Class Modification ?

From: [email-masked] (SanJeev Rampal)
Date: Tue, 20 Feb 1996 10:48:24 -0500 (EST)

The delay bound for the guaranteed delay class includes a `b/R' term 
to account for the fact that on a link which uses a rate enforcing scheduler 
(such as WFQ), a session is always guaranteed a clearing rate of `R' (at 
least). 

However, if we have an end-to-end path comprised solely of network elements  
which {\em do not} employ such rate enforcement, then there should be no need 
for this term. In such a case, every network element will simply contribute 
to the `D' term of the end-to-end delay bound and the sum of the worst case 
per-hop delays will be the worst case end-to-end delay. 

Hence, there should be some provision in the PATH message to indicate 
whether a rate enforcing scheduler has been encountered yet. Also 
the delay bound calculation in the receiver should be changed as follows : 
If atleast one rate enforcing server has been encountered by the PATH message 
by the time it reaches the receiver, then the receiver should use b/R + C/R + D
as the delay bound else it should simply use D. 

Are these statements correct ? Comments welcome.  

Sanjeev.