Subject: ATM-LSR do they use OSPF/IS-IS or PNNI??

From: "MP LS" <[email-masked]>
Date: Wed, 18 Apr 2001 10:02:29 +0200

Hello all,

I have some questions becasue something is verry strange to me.
I just assumed that ATM-LSRS used an IP routing protocol (IGP) just for 
finding the topology of the network.

But last i read an doccument and there they described that When you change 
an ATM switch to an ATM-LSR it will use PNNI instead of a IGP for IP. Can 
anyone make this clear for me??

Thanks a lot.

Greetings,

Niels Sitters.

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From: Zhi Hao Hong <[email-masked]>
Date: Wed, 18 Apr 2001 16:11:22 +0800

Cisco have OSPF support several years ago.
Thanks.

At 10:02 2001-4-18 +0200, MP LS wrote:
>I just assumed that ATM-LSRS used an IP routing protocol (IGP) just for finding the topology of the network.
>
>But last i read an doccument and there they described that When you change an ATM switch to an ATM-LSR it will use PNNI instead of a IGP for IP. Can anyone make this clear for me??
>
>Thanks a lot.
>
>Greetings,
>
>Niels Sitters.
>
>

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From: Robert Raszuk <[email-masked]>
Date: Wed, 18 Apr 2001 01:19:43 -0700

> an ATM switch to an ATM-LSR it will use PNNI instead of a IGP for IP.

No way :).

R.

> MPLS wrote:

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From: Geoff Bennett <[email-masked]>
Date: Wed, 18 Apr 2001 11:14:37 +0100

Hi Niels,

There may be some confusion arising depending on how you configure the ATM
switch.  In effect there are three modes of operation for this device...

1.  Pure ATM.  In this case the switch will operate UNI and NNI interfaces,
and will run PNNI as its routing protocol (PNNI is both an IGP and EGP).
UNI and PNNI signalling will happen on VCI 5.

2.  Pure MPLS.  In this mode, there is no ATM signalling, and no PNNI.
MPLS routing and signalling (OSPF, ISIS, CR-LDP, RSVP-TE, etc.) will pass
over VCI 32 (note, please check the latest draft for the actual VCI number,
it's a while since I read this info).

3.  Ships in the Night (SIN).  In this case, both ATM and MPLS Control
Planes operate simultaneously.  ATM signalling happens on VCI 5, and MPLS
signalling on VCI 32.  VCs that are set up as a result of signalling are
"owned" by one or other of these control planes.   SIN would allow an
operator to continue to run high revenue voice services (and maybe existing
Frame Relay or native ATM services...they make money too)  over the ATM
"character" of the switch.  They can then run the loss-making Internet
services over the MPLS character.

I think there are ideas floating around about a more integrated control
plane for ATM/MPLS switches based on PNNI, but I don't think these have
made it to draft as yet.

Cheers,
Geoff

At 10:02 18/04/01 +0200, MP LS wrote:
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Geoff Bennett                             								Tel: (33) 497 21 43 62
Director of Technology, OCTO               						Fax: (33) 497 21 43 50
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From: Robert Raszuk <[email-masked]>
Date: Wed, 18 Apr 2001 01:19:43 -0700

No way :).

R.

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From: shen jing <[email-masked]>
Date: Wed, 18 Apr 2001 17:38:49 +0800

> UNI and PNNI signalling will happen on VCI 5.

I don't think this will happen in real world , because MPLS integrate
IP routing and switching mechanism. As it uses ATM switch as transit stage
solution, it has to use SIN style equipments. While, it will go to pure MPLS in
future. If PNNI is used as routing procedure, it should be the situation where
ATM switch path is used as tunnel for MPLS.

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From: Geoff Bennett <[email-masked]>
Date: Thu, 19 Apr 2001 16:58:59 +0100

Actually Option 1 does, and will continue to happen in the real world.

Apart from ATM's use as a Traffic Engineering plane in "conventional" IP
networks, it is used in a number of other service architectures.  The
common factor for these services is that they provide high revenue to the
Service Provider.  Currently MPLS does not do this (actually this is
unfair...MPLS may well provide high REVENUE, but it does not provide high
EARNINGS).  Note, that MPLS is beginning to offer "value-added IP services"
such as VPNs, but it's not clear yet whether these services actually
operate at a profit, or just at a lower loss than best effort (ie.
Internet) IP services.

For the near to mid-term future, the DSL market will ensure that bother the
pure ATM and the SIN model will continue at the edge of the network.  The
DSL market is very dependent on local regulatory and market conditions, so
I don't want to make specific comments, but in general the view is that
ADSL specifically can generally demonstrate an ROI within 2 years, assuming
the ADSL has an ATM network behind it in order to support high revenue
voice services.

Cheers,
Geoff

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From: Geoff Bennett <[email-masked]>
Date: Thu, 19 Apr 2001 16:58:59 +0100

Cheers,
Geoff

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