The MPLS-OPS Archive

[Christopher Lewis <chrlewis@cisco.com>]

OK, here's a really simple view from an IP rather than ATM background :-)

With ATM connections, the resources needed for the VC are defined at setup 
time and resources are reserved along the VC path for that VC. ATM CAC is 
still in the control plane AFAIK. In MPLS, resource reservations are also 
in the control plane, so to make them "hard" a policer has to make sure 
that only the amount of traffic of a certain type that matches the 
reservation for that traffic type enters the network. So if you reserve 100 
Meg through a TE tunnel for high priority traffic and CAR ensures that no 
more than 100 Meg of high priority traffic is allowed in to the network, 
things are fine and pretty much equivalent to ATM guarantees IMHO. Of 
course, this requires co-ordination of two different features to ensure you 
get what you want, which is obviously more administration, but it seems 
possible to me. Maybe an NMS/OSS vendor opportunity to make something that 
keeps track of this for the service provider?

Perhaps if there are specific questions on the docs referenced in the link 
below you could let me know?

Chris

At 05:29 AM 1/28/2002, Jacinto Velasco wrote:


>People,
>
>My background is ATM with an IP component and only recently I joined this
>MPLS world. I have been reading discussions,White Papers, Tech Notes... on
>QoS, CoS and DiffServ for MPLS and could not yet find a white paper or
>equivalent that put some light on those issues, also I have notice within
>the MPLS-distr-list several e-mails asking for such info again and again...
>. From what I have read I could not see any clear method to guarantee a
>real QoS in mpls that convinced me (remember I come from the ATM world),
>it`s always a sort of... , theres a big cloud behind it for me and probably
>for some other people.
>
>Do you have any documentation or sites you can re-direct me that puts some
>light on this issue.
>
>
>Regards,
>
>Jacinto Velasco
>Marconi
>Senior Systems Eng. (Broadband Routing&Switching)
>(Embedded image moved to file: pic32237.pcx)
>
>Marconi Iberia S.A
>C/ Caléndula, 93
>Minipark III Edificio E
>El Soto de la Moraleja
>28109 Alcobendas
>(Tel:  +34 91 229 40 82 (directo)
>(Tel:  +34 600 999 482 (movil)
>(Tel:  +34 91 229 40 00 (centralita)
>2Fax  +34 91 229 40 75
>*E-mail: jacinto.velasco@marconi.com
>
>
>
>Christopher Lewis <chrlewis@cisco.com> on 28/01/2002 03:57:14
>
>To:   <saqibj@margallacomm.com>
>cc:   <mpls-ops@mplsrc.com>
>
>Subject:  Re: Guaranteed QoS using MPLS?
>
>
>With the caveat that the amount of traffic the application will send is
>known prior to the network being setup to service that level of traffic,
>yes.
>
>Try http://www.cisco.com/warp/public/732/Tech/mpls/mpls_techdoc.shtml
>
>This link shows how this can be done on Cisco networks by combining diff
>serv QoS and MPLS traffic engineering capabilities. This combination used
>to be called Guaranteed bandwidth services, but was changed to diff-serv
>aware traffic engineering. For this to work properly, a policer at ingress
>is necessary for the traffic eningeered tunnels to really function as you
>want.
>
>Chris
>
>At 06:36 PM 1/27/2002, Saqib Jang wrote:
>
>
> >Could MPLS be used to provide "virtual circuits"
> >for IP applications having specific QoS requirements.
> >For example, could MPLS be used to create guaratee QoS
> >across an IP core for an application that requires
> >no more that .1% packet loss? Do existing MPLS routers
> >have such capabilities or would this require implementing
> >a new MPLS standard?
> >
> >Also, how would an MPLS LER classify traffic that uses
> >dynamic port numbers (e.g. SIP)?
> >
> >Saqib
> >
> >Margalla Communications, Inc.
> >3301 El Camino Real, Suite 220
> >Atherton, CA 94027
> >(650) 298-8462 (W)
> >(650) 274 8745 (C)
> >(650) 368-8198 (F)
> >saqibj@margallacomm.com
> >http://www.margallacomm.com
> >
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