>At 8:29 PM +0000 6/25/03, Hemingway wrote: > > The main differences being that >> >> a.) the FR switch typically doesn't learn the DLCI numbers dynamically, >> rather the service provider needs to configure it hop-by-hop, and >> >> b.) the DLCI is not a globally unique identifier, like the MAC address in >> the case of an Ethernet switch, rather has only local significance and it >> might change along the path (aka PVC) from switch to switch. > > >Actually, there is such a thing as a "universal" DLCI. PVO and I and a >couple of other folks researched this thoroughly one Saturday a couple of >years ago. It is an extension to the standard, and allows( going from memory >here ) for an extended DLCI field that supports a 15 bit identifier. This >means that a unique DLCI is assigned to every customer device in the cloud.
The DLCI field is actually infinitely recursively extensible, not just to 15 bits. But there's a reasonable question -- why try to make a connection-oriented L2 service do what IP or MPLS can do more flexibly? > >To my knowledge, no telco supports this, for a lot of reasons, not the least >of which is the complexity and the lack of capacity to support end to end >across several provider networks. > >An enterprise running it's own frame network, say using Stratacom equipment, >for example, might find this of value. How would this be superior to simply routing, where you have IP addresses? I suppose that if you had the Stratacoms and couldn't afford to get rid of them... > >I've done a couple of quick looks on CCO and have not found any links. My >recollection is that we researched outside of cisco to find the info, and >there may be some links on CCO but my phrasing is not turning them up > >just another bit of pretty much useless information I've run across over the >years. :-> The standards-speak is recursive extensibility, but I doubt Cisco supports it -- it doesn't solve problems for which there isn't a better solution. People forget the origin of Frame Relay: it was intended as a low-speed access service to ATM. The Gang of Four popularized it as a general interface, just as the ATM Forum popularized UNI. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71385&t=71263 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
