The MPLS WG Archive

[shen jing <jshen@cad.zju.edu.cn>]

> 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.

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.


>
> 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:
> >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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> ================================================================
> Geoff Bennett                                                                                           Tel: (33) 497 21 43 62
> Director of Technology, OCTO                                                            Fax: (33) 497 21 43 50
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