Talk:Multiprotocol Label Switching
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Is MPLS a protocol? Should the category be changed to Network protocols? - Sridev 21:05, 16 Aug 2004 (UTC)
- Well, yes and no. MPLS is more of a packet format, along with some simple processing rules for forwarding packets in that format. Whether that makes it a protocol is kind of a theological question. The MPLS spec is mostly there to allow people to build compatible hardware. You also need (in most cases) a setup protocol - which you may or may not consider part of MPLS (there are several different alternatives) - before packets can flow. Noel 07:57, 25 Oct 2004 (UTC)
Wire format + Semantics = Protocol. --Koshua 03:19, 7 Jan 2005 (UTC)
"Label Lookup and Label Switching [...] can take place directly into fabric and not CPU."
It would be nice to provide some explanation of this statment... why is this so? And re: a few paragraphs earlier, *why* was it so challenging ("impossible") "to forward IP packets entirely in hardware"? These are offered as a motivation for why this subject is important, but it's not explained (or linked) well enough to be understood. DKEdwards 00:31, 21 October 2006 (UTC)
I agree. Also, the link associated with the word "fabric" does not appear to work at the moment. Simeon Williamson 14:49, 9 November 2006 (UTC)
MPLS is now also used in Ethernet Switching
Historical note that I thought was a little too detailed to go into the article - Tag Switching was originally Cisco's response to Ipsilon's high-speed switching product. (This was back from when everyone "knew" that switches could run faster than routers, and Ipsilon's clever marketing of their system [which used ATM switches] was proving vey effective.)
Another detail note: the issue with queueing delays and voice is that for voice to work, it needs to have low jitter (i.e. delay variance). You can get this in one of two ways: i) Have a big playback buffer, which allows you to smooth out the jitter, but which is (or was) expensive, and also increased the delay across the channel - and human conversational mechanisms tend not to work well with high-delay channels, or ii) Build a system with low delay and low jitter, for which you have to have short queueing delays, for which you have to have cells (a la ATM) on slow (and T1 was common when ATM was done) links if you intend to also carry large datagrams. Noel 07:57, 25 Oct 2004 (UTC)
In addition to MPLS, If I may suggest that a specific note be made on G-MPLS or Generalized MPLS. This is to basically to reflect the extension of MPLS into the time, wavelength, and fiber paradigm. The IETF common control and measurement plane (CCAMP) are working on standardizing the network plane across such multiple domains. http://www.ietf.org/html.charters/ccamp-charter.html
[edit] Does the Experimental Bits section make sense?
I couldn't figure out that the Experimental Bits section made sense at all.
In the MPLS presentations I've seen, multiple tunnels between the same endpoints are used all the time - exactly because one can apply QoS differentiation to different tunnels. In fact, lots of the time, MPLS networks are sold as "this is the solution to the QoS problem". Delete section? --Alvestrand 08:23, 9 January 2006 (UTC)
- Sad. It's documented here: [1]. --Alvestrand 15:51, 28 January 2006 (UTC)
I would take issue with the 'MPLS Deployment' and 'Competitor to MPLS' sections that refer to MPLS working in an IPv4 or IP-only environment as it is also supported in IS-IS environments.
I agree, MPLS doesnt care about L3 protocols when making forwarding decisions, it puts a 32 bit label in between the L2 and L3 headers. --Skydivemayday 03:01, 20 October 2006 (UTC)
Also, while ASICs have increased routing speed, they have done nothing to help with the fact that there are a variety of L2 transports deployed (ATM, Frame Relay, Ethernet, and SONET) which take a bit of work to interconnect every time you need to get from point 'A' to point 'B' and you would have to traverse these different types of L2 environments. MPLS adds an 'abstraction' layer which, when coupled with the VPN capability, reduces the amount of provisioning required.
If any comparisons to L2TPv3 are to be made, it should also be noted that MPLS supports both point-to-point and multipoint VPNs and L2TPv3 truly is IP-only and point-to-point. Joseph chapman 04:09, 24 April 2006 (UTC)
[edit] QoS topics missing
MPLS is everywhere described as being the ultimate solution to QoS problems by supporting Integrated Services (IntServ) and Differentiated Services (DiffServ) at the same time. It can also be used in traffic engineering for things like load balancing on ip-networks (because it's not using shortest path routing like ip always does) and defining backup paths in the case of network failure.
I think these things should be added because for a lot of internet service providers and other communication companies these are the main reasons for using mpls and, of course, as a replacement for atm. A lot of telco companies are now offering voice over ip and tv over ip so for them mpls is a way for ensuring QoS (which is of great importance for realtime services).
06:46, 01 October 2006 (UTC)
