goodloe@xenon.UUCP (Tony Goodloe) (12/22/88)
with regards to FDDI: what is the distinction between "wrapping" and "bypassing"? thanks in advance.
kwe@bu-cs.BU.EDU (kwe@bu-it.bu.edu (Kent W. England)) (12/24/88)
In article <140@xenon.UUCP> goodloe@xenon.UUCP (Tony Goodloe) writes: >with regards to FDDI: what is the distinction between "wrapping" and >"bypassing"? thanks in advance. I am familiar with the terms from Pronet-80 and I assume they carry over intact to FDDI, but wrapping and bypassing are descriptive terms. "Wrapping" is when a dual link goes down (infamous backhoe cut) and the nodes on each end of the failed link detect the loss of primary and secondary rings and loss of neighbor and then they "wrap" the primary and secondary rings together, connecting the two counter-rotating rings together into a single ring in the shape of a "C". Full connectivity restored. "Bypassing" is when the FDDI node detects a problem with the local ring or host and disconnects the local network from the backbone. It bypasses a failed or inactive host/ring. This maintains the two counter-rotating rings intact and fully operational, since the bypassing node is repeating frames around the ring and is fully participating in the dual ring management, etc. It's a necessary token ring fault management technique. Kent England, Boston University