Re: Question about logical link in Link bundling

[Maarten Vissers <mvissers@lucent.com>]

Debanjan,

Just a thought... those 12 DS3s terminating on the same router (and
providing access to 12 MPLS links) may terminate at the other ends on 12
different routers. With one physical (OC12) interface you have now made
(with the help of the transport network) connections with 12 other
routers. Very cost effective... 

Ofcourse you don't need a DS3 to be present in the STS1 is the router at
the other end of the transport network has a EC1 of (channelised) OC-N
interface. In this case you may deploy direct mapping of MPLS into STS1
payload (via PPP/HDLC or the new GFP encapsulation).

One further cost reduction step (for the case there are e.g. only 5
other routers connected) is to use STS1 virtual concatenation with GFP
encapsulation of MPLS. You can now size each of the 5 STS pipes between
1 and a Xi STS1s (STS-1-Xv) as long as the sum of X1+X2+X3+X4+X5 <= 12.

Regards,

Maarten

Debanjan Saha wrote:
> 
> Fong,
> You're right. A channelize OC-12 can have 12 DS-3s (STS-1)within it.
> However, if all of them are terminating on
> the same LSR, I'm not sure why you'll use a channelized
> OC-12 and not an OC-12c.
> 
> Debanjan
> 
> -----Original Message-----
> From: Fong, Man Wing [mailto:MFong@WhiteRockNetworks.com]
> Sent: Tuesday, May 08, 2001 5:04 PM
> To: 'Bala Rajagopalan'; mpls@UU.NET; 'Kireeti Kompella'
> Cc: ccamp@ops.ietf.org
> Subject: RE: Question about logical link in Link bundling
> 
> Bala,
> 
> Correct me if I am wrong. For my understanding, a channelized OC-12
> interface can support 12 channels (12 logical DS3 interfaces). Some even
> capable of defining logical interface within those DS3 channel to support
> T1. Then, each logical DS3 interfaces can create a (logical) link to the
> remote routers' DS3 interfaces. The original used of the channelized OC-12
> interface is to reduce the cabling and additional equipment cost and labor
> cost at the central location. Since it is a channelized interface, I
> believe, it would not allow the user to use it as an OC-12c interface. By
> applying link bundling on that, now you can size your pipe whatever you want
> upto the maximum BW (in this case, it will be STS-12c). In addition, using
> O-UNI, you will get a true bandwidth on demand.
> 
> Just a thought.
> 
> Man Wing
> 
>  -----Original Message-----
> From:   Bala Rajagopalan [mailto:BRaja@tellium.com]
> Sent:   Tuesday, May 08, 2001 3:24 PM
> To:     'Fong, Man Wing'; mpls@UU.NET; 'Kireeti Kompella'
> Cc:     ccamp@ops.ietf.org
> Subject:        RE: Question about logical link in Link bundling
> 
> Hello,
> 
> I'm a bit confused by the question. If you
> had a channelized OC-12 link, wouldn't you
> just advertise it with suitable Min Reservable
> Bw values to indicate that it can carry lower
> granularity traffic? In other words, why would
> you introduce the notion of a "logical" link
> in this case?
> 
> REgards,
> 
> Bala Rajagopalan
> Tellium, Inc.
> 2 Crescent Place
> P.O. Box 901
> Oceanport, NJ 07757-0901
> Tel: (732) 923-4237
> Fax: (732) 923-9804
> Email: braja@tellium.com
> 
> > -----Original Message-----
> > From: Fong, Man Wing [mailto:MFong@WhiteRockNetworks.com]
> > Sent: Monday, April 30, 2001 3:31 PM
> > To: mpls@UU.NET; 'Kireeti Kompella'
> > Cc: ccamp@ops.ietf.org
> > Subject: Question about logical link in Link bundling
> >
> >
> > Hi All,
> >
> > From "draft-kompella-mpls-bundle-05.txt", it indicates that
> > multiple links
> > between two LSRs can be bundled as a single link to improve
> > the routing
> > scalability. Apparently, it can be used to bundle multiple links from
> > multiple physical interfaces (e.g. multiple T1s, DS3s, OC-12s, OC-48s,
> > etc...) to be a single link. However, can it be used to
> > bundle logical links
> > like T1s in channelized T3, or DS3s, STS-3c in channelized
> > OC-12 interface?
> >
> > Thanks.
> >
> > Regards,
> > Man Wing
> >
> >
> >
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