Re: Alternative to draft-ash-mpls-diffserv-te-class-types-00.txt ?

[Balazs Szviatovszki <Balazs.Szviatovszki@eth.ericsson.se>]

I suppose the idea behind higher priority for control traffic is to assure proper link-state routing operation in sever overloads. Check out this draft:

<draft-ash-ospf-isis-congestion-control-01.txt>  
"Proposed Mechanisms for Congestion Control/Failure Recovery in OSPF & ISIS Networks"

Still, I would not dare to say that there should not be preemption among other non-control traffic types. Recall, the draft of Jim, proposed that it should be configurable which class-type could preempt which one <draft-boyle-tewg-ds-nop-00.txt> : 

            class voice use priority 2
	    class data use priority 4
	    [mpls preempt <yes|limited|map|no>]
----------> [preempt map voice over data]
	    [class mute <list>]

Previous idea was that higher priority can preempt any lower priority. I think this is the concept actually coded in many MPLS implementations. 

Balazs


"Naidu, Venkata" wrote:
> 
> Wai Sum:
> 
>   I didn't understand why control traffic is so different?
>   Draft recommends, no preemption of LSPs and/or transport
>   links across CTs, except for control-traffic CT. (Why?)
> 
>  * I mentioned my concern about CT6 because, control traffic is
>    also *some data* in IP sense. For good example, I can send
>    OSPF/RSVP Hellos in one particular CT and all other Control
>    messages (updates etc) in other CTs. Don't you agree?