Specifications

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Cisco IGX 8400 Series Provisioning Guide, Release 9.3.3 and Later Releases
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Chapter 3 Cisco IGX 8400 Series Nodes
IGX Network Management
Specifying Channel Utilization
Use the cnfchutl command to specify the expected utilization of Frame Relay, data, or voice channel as
a percentage of the channel’s total capacity. The specified value can be in the range of 0 to 100 percent;
100 percent is the default for data and Frame Relay channels. The default for voice channels is
60 percent. To display the utilization of a particular trunk, use the dsptrkutl command. This command
displays a details on the packets transmitted over the trunk. The user can specify the rate in seconds at
which the screen is updated. Use the dspload command to display the load for a specified trunk at a
node.
Specifying Class of Service
Use the cnfcos command to specify a class of service (CoS) for a Frame Relay, data, or voice channel
connection. The class of service is the delay in seconds before the network reroutes a connection in the
event of a trunk failure. The range is 0 to 15. By spreading out the CoS numbers to vary the rerouting
delay, one class of connections has a chance to reroute before the other class starts to reroute.
Specifying Priority Bumping
Priority bumping allows both BPX and IGX connections that are classified as more important (via CoS
value) to bump existing connections that are less important, when network resources become scarce.
While the existing Automatic Routing Management feature is capable of automatically redirecting all
failed connections onto other paths, use the priority bumping command, cnfbmpparm, to activate the
priority bumping feature in order to retain important connections when network resources are
diminished to a point when all connections cannot be sustained. Network resources are reclaimed for the
more important connections by bumping (or derouting) the less important connections. Priority bumping
is triggered by insufficient resources (such as bandwidth) resulting from a number of events, including
changes to the network generated by the addcon, upcon, cnfcon, cnfpref, cnftrk, and deltrk
commands, by a trunk line or card failure, or by a node failure. The most typical event is a trunk failure.
In priority bumping, connections are defined by their Class of Service (CoS) value. Connections tagged
with the lowest CoS, zero, are the most important to maintain. Connections tagged with the highest CoS,
15, have the lowest priority. Connections that have a CoS value in between 0 and 15 are progressively
less important as they ascend upward.
The CoS values are categorized into a set of 8 bands. These bands can be configured to meet the specific
needs of each network. For information on the default settings used when priority bumping is enabled,
see Table 3-3.
Note Configuring priority bumping requires a thorough knowledge of AutoRouting capabilities (also known
as Automatic Routing Management) available bandwidth, and CoS values.
Table 3-3 Default Settings for Priority Bumping
Band012345 6 7
CoS 0/1 2/3 4/5 6/7 8/9 10/11 12/13 14/15