[Irtf-rr] Re: AW: Differentiated Routing, not only plain rambo-SPF

[shen jing]

Hummel,

> 
> Gold:  A smallest size tree of toll roads, highways, state roads, country roads.
> Silver:A smallest size tree of highways, state roads, country roads.
> Bronze:A smallest size tree of state roads, country roads, and highways only if no path otherwise.
> 
> QoS parameters (speed, packet loss rate, MTU size,..) may define the type of road.

Do you means to restrict DSCP to be 3bits? 


> 
> 1st and 2nd road system may be different at least  w.r.t. their kernel parts. (The kernel part be that
> center of the smallest size tree, which is used by at least m ingress/egress combinations).
> Either traffic starts out with a) proper DSCP-Y-1st, resp. DSCP-Y-2nd, or b) is  changed from DSCP-Y-1st to
> DSCP-Y-2nd at the rim of the kernel if some current traffic load information advises so. I prefer a) and if possible such
> that any microflow will entirely take one single route.

So, that means to use alternative path for overflowed traffic?  In fact,
someone has proposed similar

method. Perhaps you are interested in the following paper:

http://www.cs.virginia.edu/~rv3s/pubs/compnet_paper.pdf 

> 
>
> Stability:
> We may toss a dice at the ingress,i.e. determine a random number Y between 0.0 and 1.0. 

I think this determines when a second path is adopted for traffic
routing, in fact we do not
need to use a random number if MPLS is used. At this situation, I think
what we need is to 
monitor load on a LSP, if the load is more than 70% of the effective
bandwidth another LSP is
adpoted. If distributed routing is used ( as that of current IP
network), traffic dispersion 
have to be triggerred by heuristic method mentioned by you.

> 
> Extensibility:
> So far I have no solution, on how to determine a smallest size tree made out of OSPF-links and EBGP/IBGP-hops.

As I think, a routing system built on time-varying network status will
do harm to both
stability and extensibility, because it could not be expected to all
routers converge to the same 
point within a short time period. 

Some others have been working on resource management in DiffServ
networks, the page located 
at:

http://standards.ericsson.net/rmd/

In deed, I'm very interested in this idea but I think it need more
clarification.

Hope to hear from others.





-- 
Jing Shen

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

Tel: +86-571-87932423

Email: jshen@cad.zju.edu.cn

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