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Configuring PNNI Routing
PNNI Routing Protocol Overview
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000 1/19/0521-13
Logical Port and Protocol Types
In Lucent’s PNNI implementation, you can configure both virtual and direct PNNI
logical ports. When you use Navis EMS-CBGX to configure PNNI logical ports, the
logical port type is ATM NNI, and the protocol type is PNNI 1.0.
PNNI Administrative Weight
When you configure a logical port, you can assign an administrative weight to each
Quality of Service (QoS) category. This weight allows you to configure the network to
favor one path over another path for a given QoS category, when the path constraint
for an ATM virtual circuit (VC) is administrative weight. The weights of all the
network interfaces along a path are added up. Switches choose the path with the
lowest cumulative weight when making routing decisions, assuming that all links can
provide the resources requested by the call.
The following examples describe how PNNI administrative weight configurations can
function in a PNNI network:
• Suppose that variable bit rate-real time (VBR-RT) traffic has two available paths
for reaching a given destination. One path has a weight of 1000 while another path
has a weight of 4000. The switch will choose the path with the weight of 1000, if
the call requests VBR-RT QoS and administrative weight as a metric and if the
path has sufficient bandwidth and other metric resources.
• In a network that supports both constant bit rate (CBR) and unspecified bit rate
(UBR) calls, PNNI administrative weight values can be configured so that the
switch will choose one path for the CBR calls and a different path for the UBR
calls.
For information about configuring PNNI administrative weight parameters, see
Table 21-7 on page 21-52.
Note – Administrative weight (Admin Cost) is the default routing metric.
Administrative weight is not used if you select a different routing metric (end-to-end
delay or cell delay variation [CDV]). For more information about routing metrics, see
“Setting QoS Parameters” on page 3-51.
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