MPLS in metro access networks

Michael Cohen mcohen at thrupoint.net
Thu Nov 15 17:20:26 UTC 2001


I still have to disagree that MPLS results in faster switching/routing in
modern service provider networks.  Modern vendor caching mechanisms are just
as fast if not faster than MPLS processing.  With the small overhead of MPLS
labels and LDP I highly doubt that you're getting any performance increase
over Cisco's CEF or Juniper's FPC architecture.  I also doubt that speed is
a benefit that service providers consider when deciding whether or not they
want to implement MPLS.  Added services that run on top of MPLS like VPNs,
traffic engineering, and fast rerouting capabilities (all mentioned in the
original post) are more likely the benefits considered.  Perhaps when label
switching was first being marketed (Ipsilon and Cisco in 1996) there were
some speed benefits but now I think it's the services that use MPLS that are
the major benefit.

-Michael Cohen

-----Original Message-----
From: Quibell, Marc [mailto:mquibell at icn.state.ia.us]
Sent: Thursday, November 15, 2001 10:59 AM
To: 'mcohen at thrupoint.net'; 'nanog at merit.edu'
Subject: RE: MPLS in metro access networks


soooo...Label switching assigns labels to packet headers which results in
less time and processing looking up routes, and instead relies upon a label
index for forwarding decisions? Hence my statement "faster switching/routing
and less processing":)

Marc



-----Original Message-----
From: Michael Cohen [mailto:mcohen at thrupoint.net]
Sent: Thursday, November 15, 2001 10:56 AM
To: Quibell, Marc
Subject: RE: MPLS in metro access networks


I hope so:)

-----Original Message-----
From: Quibell, Marc [mailto:mquibell at icn.state.ia.us]
Sent: Thursday, November 15, 2001 10:46 AM
To: 'mcohen at thrupoint.net'; nanog at merit.edu
Subject: RE: MPLS in metro access networks


Are we talking about Multiprotocol Label Switching?

Marc


-----Original Message-----
From: Michael Cohen [mailto:mcohen at thrupoint.net]
Sent: Thursday, November 15, 2001 10:45 AM
To: nanog at merit.edu
Subject: RE: MPLS in metro access networks



And I'm not sure what faster switching/routing has to do with MPLS:)  I
believe one of the ideas behind MPLS benefiting metro access networks is
using MPLS to deliver layer 2 VPNs across an MPLS enabled core thus
simulating leased lines for access clients...but I'm sure somebody will
correct me if I'm wrong.  There seems to be some hype for Martini draft VPNs
and large enterprise customers in metro areas.

Cheers,

-Michael Cohen

-----Original Message-----
From: owner-nanog at merit.edu [mailto:owner-nanog at merit.edu]On Behalf Of
Quibell, Marc
Sent: Thursday, November 15, 2001 10:20 AM
To: 'srihari varada'; nanog at merit.edu
Subject: RE: MPLS in metro access networks



I would think faster switching/routing and less processing would be wanted
in any mid-to-large sized network...I'm not sure what load balancing and
fault restoration has to do with MPLS....

Marc



-----Original Message-----
From: srihari varada [mailto:varada at txc.com]
Sent: Thursday, November 15, 2001 10:12 AM
To: nanog at merit.edu
Subject: MPLS in metro access networks


Hello:

I have heard some stressing the role of MPLS in metro access networks.
It is difficult for me to visualize the need for it in them while it
is not so difficult to understand the utility (load balancing and fault
restoration etc.) of it in the metro backbone networks.

To characterize metro access networks in the context, the following is
provided:
-- aggregates traffic from residential (arriving via broadband access
   links such as xDSL, Cable) and business consumers (arriving via
broadband access links such as
   xDSL and high speed links such as Ethernet or SONET)
-- funnels aggregated traffic to metro backbone networks for destination

    hosts in the local metro region or remote regions across the
internet regional
   and backbone networks. Majority of such access networks are SONET/ATM
based (I didn't come
   across any case of Gig Ethernet. However, I do not preculde it).

Thus, there are two questions:
-- Are there known RBOCs/ILECs and CLECs entrenching MPLS in the said
   network scope? (I do not see many major ILECs in the un-official MPLS
service
   providers list being circulated but it may mean little)
-- If so, what motivates them to do so? Any analysis of the driving
forces is appreciated.

Regards,

Srihari Varada




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