> > And in that space, MPLS is rapidly catching up as an alternative to >> ATM and raw SONET. It's no accident it's called "ATM without cells". >> MPLS, and especially MPLS VPNs, do have more of a telco learning >> curve than ATM. > >At the risk of starting a religious war, I've never understood why MPLS is >so IP-centric. It's not called IPLS, it's called MPLS. With only a few >exceptions, most MPLS initiatives I see presume that devices are running an >IP stack to handle control-plane mechanisms.
Look at the evolved GMPLS specification, which deals with wavelengths, time slots, and physical ports as well as packets. Their payloads are definitely not limited to IP, but could involve SONET/SDH frames, lambdas, etc. In the ATM world, PNNI certainly is more evolved than standard OSPF, but it still would need extension for current concepts of traffic engineering. Why do the work twice, once for IP and once for ATM? Optical routing is another concern; I've been bothered that layer 1 optical folk again are reinventing routing algorithms usually described as "based on OSPF," but that really aren't that different than OSPF with additional constraints and the opaque LSA. > >MPLS in its original conception seemed to have the potential to be a perfect >drop-in replacement for ATM. But only if MPLS incorporated all the ATM >signalling parameters, which hasn't really been implemented (there has been >some work done, but I would contend that the amount of IP-signalling work >done and the amount of ATM-signalling work done is at least 10:1) I'm not sure which parameters you have in mind. Q.2931? Are you thinking more of telephony function support or QoS? Where do you see SS7 and OSS networks fitting in this? One of the arguments being made is that separate SS7 networks are dead anyway, and IP routed OSS networks are a logical place to put them. >. >Instead, practically all MPLS interworking proposals for ATM presume that >the ATM devices be upgraded with IP or somehow speak to another device that >does ATM and IP/MPLS translation. Is this really necessary? Because of all >the installed base of ATM out there, forcing them to do this interworking in >order to incorporate MPLS just means greater resistance to it and ultimately >a slower uptake of MPLS. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=53820&t=53737 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
