Cabletron Systems Smart 04-0053-01 - Manual (Page 55)

SmartSwitch ATM User Guide 3-11
PNNI Routing Managing Parallel PNNI Links
The physical connection from switch SWA2 to switch SWB2 is now advertised as a second logical link within the
parent peer group (see Figure 3-4).
Figure 3-4 Aggregation token values and parallel links
3.3.2 PNNI Link Timing
By default, if a PNNI link loses connectivity, the link fails after three (3) seconds. This short amount of time is designed
as a buffer in case of minor latency. By waiting three seconds before releasing resources and tearing down the
connection, a minor latency occurrence (less than three seconds) will not bring the link down, and will keep the PNNI
network from going through the process of reconfiguration.
Note Link failure is determined either by hardware, when a “loss of frame” is detected;
or by the signaling software, when the QSAAL link goes down.
Level 72
First Logical link
First Physical
Link
SWA1
SWA2
SWA3 SWB1
SWB2
SWB3
Second Physical Link
Second Logical Link
Aggregation Token = 0 Aggregation Token = 1