Appeal No. 2000-0330 Page 2
Application No. 08/684,871
network. ATM cells received at the first switching node are
duplicated to be transmitted to the second switching node via
both paths. Normally, only cells arriving via the main path are
forwarded by the second node; cells arriving via the substitute
path are suppressed. Upon a malfunction of the main path,
however, cells arriving by the substitute path are forwarded by
the second node; cells arriving by the main path are suppressed.
The different routes of the main and substitute paths can
cause the paths to operate with different network transit times,
which results in a “shift” in the reception of cells arriving via
the paths. The appellant explains that for a high-rate network
featuring optical fibers, a 100 km route difference between the
two paths can cause a shift in transit time of a millisecond.
(Spec. at 1-2). For ATM cells comprising 53 octets and paths
having a rate of several Mbit/s, he adds, such a shift can cause
the loss or duplication of ten cells when a switch is made from
main to a substitute path. (Id. at 2.) To avoid such loss or
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007