NSE-8G™ Standard Product Data Sheet
Preliminary
Figure 33 Relabeled Graph
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12.13.5 Experimental Results
The performance of PMC-Sierra’s Open Path Algorithm has been studied by implementing it in
C++ and running extensive random connection tests. Tests for NSE/SBS applications of this
algorithm used a single NSE-8G connected to 12 SBSs, each carrying a full complement of DS0
connection. Many runs were completed in which an initially unloaded switch is presented with a
sequence of random call establishment requests up to the point of 100% switching loads. These
runs were carried out on a 600 MHz Alpha running Linux. In all of these runs, no otctet open path
search took longer than 10µs, thus supporting up to 100,0001 DS0 call establishments per second.
T1s and other aggregates require the establishment of multiple octet open paths; complete T1s
can be established at about 3,700 T1/sec. The reasons for this surprisingly good performance are
explained in the separate open path algorithm document. It is our opinion that these rates are
sufficiently high that the call establishment algorithm should not be a bottleneck in any
application of the NSE/SBS, and that this rate is sufficiently high to permit the NSE/SBS to be
used for PSTN call establishment rates (up to 100,000 calls/sec in a switch supporting 96,768
full-duplex calls, with the switching core implemented in 1 NSE-8G and 12 SBS chips).
12.13.6 Multicast
Scheduling general multicast connections is an entirely different class of problem. With
unrestricted multicast, the underlying architecture is non-blocking up to capacity dictated by the
number of slots in a frame, but finding the non-blocking schedule is NP-hard. There is no
polynomial time running algorithm known to solve this class of problem.
There are two approaches to solving the multicast problem:
•
Heuristic algorithms that have statistical probability of success for simple versions of the
problem; (and)
•
Restricted multicast, where the form of restriction provides a means to solve the scheduling
problem.
1 This ignores inband or uP to NSE limitations.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010850, Issue 1
162
PMC [ PMC-SIERRA, INC ]
