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7-381/19/05 ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
Configuring Trunks
Configuring APS Trunk Backup and Fast APS 1+1 for ATM Direct Trunks
7. In the Add Logical Port dialog box, select the PNNI tab (Figure 7-13).
Figure 7-13. Add Logical Port: PNNI Tab
The PNNI tab enables you to configure the PNNI administrative weight status by 
assigning an administrative weight to each QoS category. This weight allows you 
to configure the network to favor one path over another path for a given category. 
The weights of all the network interfaces along a path are added up, and switches 
choose the path with the lowest cumulative weight when making routing 
decisions. For example, suppose that VBR-RT traffic has two available paths for 
reaching a given destination: one path has a weight of 1000 and the other path has 
a weight of 4000. If the call requests VBR-RT QoS and administrative weight as a 
metric, and if the path has sufficient bandwidth and other metric resources, the 
switch will choose the path with the weight of 1000. 
In a network that supports, for example, both CBR and UBR calls, you can 
configure PNNI administrative weight values so that the switch will choose one 
path for the CBR calls and a different path for the UBR calls.