Subject: Calculation of Fixed Delay

From: Neetu Gupta <[email-masked]>
Date: Thu, 20 Jul 2000 13:57:32 +0530

Hi,
    I've a question regarding computation of Fixed Delay.

For providing QoS, we need end to end latency along the path over which
LSP is to be created. Latency includes both fixed and Variable delay.
Fixed Delay at a particular node can be set in Minimum Path Latency
Field in Adspec object of RSVP Path Message. Fixed delay includes both
processing and propagation delay.

Suppose MPLS is on ATM, we can get processing delay (of ATM Header and
Segmentation and Ressembly ) from the ATM Switch.

My question is :
How do we calculate the delay in MPLS related processing and propagation
delay?

By MPLS related processing, I mean the processing at Ingress LER which
will do forwarding of unlabelled packet which comes in. There could be
requriement for Fragementation also if the MTU sizes don't conform to
our requirement.
It is also stated in drafts that propagation delay is neglegible as
compared to processing delay. But if I wish to include it in my latency
calculation then is there any method to do so.

Thanx in advance.

-neetu