[e2e] about TE

[Ayyasamy, Senthilkumar (UMKC-Student)]

Hi all,
Though i am cross-posting..I am really confused about some features of TE.
Their was one particular mail in the TE working group about the possbility of using erlang calculations in TE .His mail also talk about alll traffic theory stuff which is basically done for traffic modelling..I have came across a wonderfull IEEE communication paper " traffic theory and Internet " which discusses the statistical characteristics of Internet traffic at different time scales.The author also indicate the limitations of service differentiation as a means for guaranteeing QoS and highlight the importance of traditional traffic engineering approaches in ensuring that the network has sufficient capacity to handle offered demand through derived results (<http://www.comsoc.org/ci/public/preview/roberts.html>) .I have mentioned about this paper sometime back.
The author at one place mentions that "Most providers systematically practice overbooking, 'allocating' available bandwidth several times over. Although this clearly violates the notion of service protection, perceived quality of service is satisfactory in most cases. It is tempting to deduce from this that reservation is not realnecessary as long as admission control is employed to protect the QoS of existing traffic" .So,like I also have a question like if traditional traffic models itself provides a way for all TE capabilities ..why is the need for TE mechanisms proposed by IETF ITEWG like service differentiation and QoS stuff all ..
After going through most of the drafts in ITEWG..i got the idea that "This WG provides some mechanisms and frame work for TE and have not concentrated much on actual TE mechanisms..please clarify in this regard ...what is the actual objective of ITEWG other than giving inputs to other Wg's like MPLS and CCAMP...Is the WG coordinate the activities of all other sub-IP wg working in this area..
This is my third question..when there are mechainsms for doing TE in IP networks itself ??? why cant they just be used..I have seen some literature in this side..really interesting works .(.http://www.research.att.com/~jrex/papers/ieeenet00.ps ) and also one other paper on the same subject (<http://smg.ulb.ac.be/Preprints/Fortz99_29.html>)....... These papers has convinced me that TE can be done in IP networks rather putting our time and energy in all multiservice networks.....so  what is the real advantage of MPLS for TE which IP networks cant provide ...The paper which you gave as a part of our course CS520 did give a reason like using non-shortest paths..Is there is any advantage other than this or is this feature brings the whole advantage of TE for MPLS networks
In a nutshell, we can view three choices for TE 
1. Traditional traffic modelling taken from the well tested telephone networks by all possion modelling ,FBM , erlang calculation and all those stuff
2. Using IP network TE as proposed by Dr.Jennifer and et all in "NETSOPE " and also by optimizing OSPF weights 
3.Use the option of Multiservice networks like MPLS to TE by service diff and other QoS optimization principles....
Can they not combine all this work and provide a posisble solution
Also one more question regarding this issue...when we  have BW why should we do TE ???? Is there is any place where we need TE mecahnisms even when their is infinite BW .
This is a question posted in TEWG but no answers.
Thanks in advance,
senthil.
AYYASAMY SENTHILKUMAR         5000,oak street
Masters in Computer networking     #twin oaks apt625  
Dept. of telecommunication            kansas city  
university of missouri                     Missouri-64112
kansas city ,MI-64112                   phone:816-531-2005