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[MPLS-OPS]: Jitter and MPLS

  • From: Jing Shen <jshen@cad.zju.edu.cn>
  • Date: Mon, 09 Dec 2002 21:00:17 +0800
  • Organization: State Key Lab of CAD&CG

alok,



> 
> I cant figure this point
> 
> are you comparing ethernet--MPLS--IP--TCP frame with ethernet--IP--TCP
> frame? well then your frame size is larger....thats about the only
> difference i see.

That's the reason. The reason why we take that is, we do not consider 
MPLS as mechanism carrying TCP packet, and MPLS is to add new mechanism 
to IP networks, so the overhead is considered to be the one affecting 
throughput. If we want o compare payload of MPLS with payload of IP,
I can't find any acceptable parameters to be compared.


> 
> yes, but lets assume that u had a scenario where the MPLS+payload(be it IP
> of anything) was compared with IP+(payload) ...where payload is of equal
> size, then what is the result? do realise your switching on a smaller
> "label" than an whole IP address....and I also assume your switching table
> is not optimized for "aggregates etc"..it depends on your switching
> mechanism.
> 

We don't want to compare aggregation situation, but want to focus on
e2e performance difference.


> 
> well, we put L2 headers in each hop too and in cases of ethernet/Multiaccess
> media, the L2 header depends on the next-hop... you would have ASICs doing
> it on the interface/FT.
> 
> according to your logic, FR interfaces should give the same
> problem.....specially on MultiAccess topologies...
> 
> >
[snip]


-- 
Jing Shen

State Key Lab of CAD&CG
ZheJiang University(YuQuan)
HangZhou, Z.J. 310027
P.R.China

Tel: +86-571-87932423
Mobile: (0)13516813753
Email: jshen@cad.zju.edu.cn

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