Re: QoS - Calculating path latency

Hey Dave,
it might be that the R2 read serialization happens exactly as (during)
R1 write serialization ? Then, they do not add up, but only one of them
is used to account them both.

-Carlos

Dave Serra @ 12/01/2013 16:41 -0300 dixit:
> I have a question. I've been reading Wendell Odom's cisco press book 'Cisco
> QoS, Exam Certification Guide'. In it he calculates total latency for the
> path as processing delay, serialization delay, propagation delay, etc... My
> question is why do we calculate serialization delay only as the packet is
> leaving the interface and being placed on the wire and not ALSO when the
> packet is being received by the remote router. Surly there is some delay to
> take an incoming packet off of the wire and store the bytes in memory prior to
> processing it. So in other words, in the network as PC1-->R1-->R2-->PC2 why
> are we not including the delay to get the packet off of the wire and into
> R2. ie, assume packet is already in R1--> processing delay, seralization
> delay of R1, propagation delay to reach R2 and then serialization delay again
> to get the packet into R2 for its processing?
>
> BTW, I know I grossly
> missquoted Odom by only including processing delay, serialization delay,
> propagation delay, etc... He has a lot more delay types in his book. My
> question really only focuses on the packet that is in R1 and getting into R2
> so I omitted the others.
>
> I appreciate anyone's feedback.
>
> Thanks guys.
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net