The only problem with this approach is the idea that you can divource a standards based approach like MPLS with the vendor specific implimentation of switching methodologies. On the Cisco platform, for example, MPLS is deeply tied into CEF, for somewhat logical reasons - Cisco saw no need to reinvent the wheel, and didn't want to go down the path of a new forwarding technology. The platforms are STILL using proprietary switching methods - they always will, as it is a distiguisher. You seem to imply that if you use MPLS, you won't be using other methods of distributed or fast switching on your routers. This simply is not the case. On Cisco's you will still use CEF, and on Junipers you will use ASIC-based FPC switching. MPLS is not useful in and of itself as a switching mechanism. However, it is useful for TE, VPNs, etc. If you enable MPLS on your network to get "better performance", "faster speeds", or a "more reliable core", you will be disappointed in the end, as the performance is the same, speed is the same, and reliability is lower due to immature code. - Daniel Golding -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of Quibell, Marc Sent: Thursday, November 15, 2001 1:04 PM To: 'mcohen@thrupoint.net'; nanog@merit.edu Subject: RE: MPLS in metro access networks I guess you answered your own question: "And I'm not sure what faster switching/routing has to do with MPLS:)" As far as CEF and such goes, I couldn't disagree with that (as I was not comparing MPLS to other optimized forwarding techniques), however, MPLS is not a vendor-proprietary forwarding mechanism, which means that I can deploy it worldwide, or state-wide, whatever the case may be, in my network and have the benefit of using only ONE protocol with MPLS-enabled/aware routers/switches. A definate plus over the other proprietary fast switching techniques you mentioned. Your last statement indicates "added services" have nothing to do with the the fast switching processing of MPLS, when in fact these services depend upon the faster delivery of the non-proprietary fast switching of MPLS. As quoted from the rfc: "This memo presents an approach for building core Virtual Private Network (VPN) services in a service provider's MPLS backbone. This approach uses Multiprotocol Label Switching (MPLS) running in the backbone to provide premium services in addition to best effort services." Marc -----Original Message----- From: Michael Cohen [mailto:mcohen@thrupoint.net] Sent: Thursday, November 15, 2001 11:20 AM To: nanog@merit.edu Subject: RE: MPLS in metro access networks 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@icn.state.ia.us] Sent: Thursday, November 15, 2001 10:59 AM To: 'mcohen@thrupoint.net'; 'nanog@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@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@icn.state.ia.us] Sent: Thursday, November 15, 2001 10:46 AM To: 'mcohen@thrupoint.net'; nanog@merit.edu Subject: RE: MPLS in metro access networks Are we talking about Multiprotocol Label Switching? Marc -----Original Message----- From: Michael Cohen [mailto:mcohen@thrupoint.net] Sent: Thursday, November 15, 2001 10:45 AM To: nanog@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@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of Quibell, Marc Sent: Thursday, November 15, 2001 10:20 AM To: 'srihari varada'; nanog@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@txc.com] Sent: Thursday, November 15, 2001 10:12 AM To: nanog@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