Jimmy wrote: > > Hi, > Sorry if the following question sound stupid to you. let say i > have 4 nodes. > > B > / > A C > / > D > > If BLSR is employed, how do i know in which direction is the > packet flow > from A to C.
Depends on how you build the cross-connects in the SONET boxes. Many products, such as Cisco's, use point-and-click GUIs that automatically choose the best path and build the cross-connects for you. Or you can manually build them however you like. It simply requires that you move from box to box through the ring and cross connect incoming STS so-and-so to outgoing line-group so-and-so. >Should it flow through B or D? What is the > criteria for > choosing the path? It's really your choice. A better illustrative scenario would be traffic between A and B. As a general rule, you'd choose the direct path vs. going through C & D - especially since you can "re-use" protection bandwith for low-priority traffic. Say you establish an STS in slot 6 between A & B. You can now establish an STS in slot 6 between A & D, D & C, and C & B. Of course, when there's a ring failure, those re-used connections are killed so that the primary traffic can be protected. This varies somewhat by vendor though. It's just a generalization. > For BLSR/2, since it mentioned half BW for transmission and > half for > protection, therefore i can say the transmission rate is BW/2 > rite? Sorta. Refer back to what I said earlier. But yes, in its purest form, a 2-fiber BLSR ring uses half of the ring capacity for working traffic and the other half is reserved for protection (in an OC-48, STS1-1 would be protected by STS1-25, STS1-2 would be protected by STS1-26...). But traffic engineering in the SONET world often isn't as simple as it seems. Revenue-generating rings are usually provisioned quite differently than, say, a high-priority "mission" ring. > Any information will be appreciated !If possible, send me notes > abt it so > that i can have a better idea. Thanks alot! www.sonet.com used to be a good source for info but appears to have been highjacked. Just use a good search engine and your bound to find plenty of info on ring architecture. > > Cheers ! Same to ya. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58118&t=58082 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
