Aaron Ajello wrote: > > This is probably a very simple concept question, but I've asked > a couple people and haven't gotten a solid answer. > > If I've got two frame relay spoke sites connected point to > point with a hub site and a server in one spoke site copies a > file to a server in the other spoke site, does all the traffic > pass through the hub site, or is it switched within the frame > cloud?
All the traffic passes through the hub site. > > I guess what I'm wondering is does a frame cloud act somewhat > like a lan, where initially packets will go through the default > gateway and be routed and then the following packets will be > switched? A frame cloud does act like a LAN but a LAN without a router (and no broadcasting, but that's another story). You mixed metaphors by sticking in the router, which is a layer up. The only reason a LAN switch can route and then switch is because it's really a router (dare I say L3 switch!? :-) Or it is in communication with a router, running Cisco's Multilayer Switching Protcol (MLSP), and has an understanding of L3 addressing. A Frame Relay switch is just a L2 switch. It really does behave quite a bit like a classic LAN L2 switch. It has a switching table that has a set of entries that say, "if packet comes in on this DLCI, it goes out on that DLCI." This is similar to a L2 bridging/switching cam table, although there are differences. The Frame Relay switch understands the virtual circuits that have been provisioned to the customer. With a hub and spoke topology, the spokes don't have a virtual circuit to each other. They just have a virtual circuit to the hub. So imagine a hub and spoke topology with Chicago being the Hub. Make Los Angeles and Miami the spokes. Chicago has two virtual circuits: DLCI 100 goes to Los Angeles DLCI 200 goes to Miami Los Angeles has just one virtual circuit: DLCI 777 goes to Chicago Miami has just one virtual circuit DLCI 888 goes to Chicago A switch in Chicago has two entries in its switching table: incoming = 100, outgoing = 777 incoming = 200, outoing = 888 A switch in Los Angeles has the following entry in its switching table incoming = 777, outgoing = 100 A switch in Miam has the following entry in its switching table incoming = 888, outgoing = 200 If you can get your hands on enough routers, set up one of them to be a Frame Relay switch in a hub-and-spoke topology. Just a switch, no routing. It's truly an eye opener to manually configure its switching table (and it is generally done manually, unlike a LAN switch.) Actually, from what I understand, there can be intermediate DLCIs in the cloud too, but that's a high-level view. Someone can correct me if I'm wrong about it. I'm a bit tired after the NetBIOS biopsy or was it a lobotomy. :-) Priscilla > > thanks. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71277&t=71263 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
