The MPLS-OPS Archive

[Sudeep Goyal <sudeepg@cse.iitb.ac.in>]

In repsonse to your question asked about DiffServ path setup, I'll make a 
try:
  Resource reservation can be done either through signalling wherein we 
use some signalling protocol (example is RSVP in case of IntServ, LDP
in case of MPLS) to reserve source for some QoS requirement we have. Here, 
we reserve resources on per flow or sometimes, on aggregate basis.

In case of diffserv, the treatment is per-hop and per-class. It is simple 
per class treatment at each hop. And therefore, in order to provide 
end-to-end proper guarantee, we use bandwidth broker kind of architecture over Diff-serv 
network. Refer to Aquila architecture (European IST project. 
http://www-st.inf.tu-dresden.de/aquila/) which provides end-to-end QoS in 
DiffServ network and it has a mechanism of signalling that ensures 
end-to-end guarantee. But, this signalling doesnot go through the core 
routers, but only edge routers.

  And i think that if you would want to provide end-to-end QoS, you would 
need some kind of signalling though.

Therefore, Diffserv is more so used in the backbone networks for 
QoS wherein we want to provide aggregated class based diferentiated 
service without any need of signalling requirements.

  My attempt to help you resolve your doubt.

regards,
sudeep




-- 
The winds and waves are always on the side of the ablest navigators.
-Edward Gibbon

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