Troubleshooting guide

6-35
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 6 Troubleshooting Switch Router ATM Network Connections
Troubleshooting PNNI Peer Group Leaders
Step 5 Use the show atm pnni election peers command to see which other peer nodes are known by a local
node. Only those nodes listed as connected are eligible to be the preferred PGL for a local node.
Switch# show atm pnni election peers
Node No. Priority Connected Preferred PGL
~~~~~~~~ ~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~~~~~
1 0 Yes NONE
Switch#
Step 6 If the expected leader still does not become PGL, check the current FSM state by using the show atm
pnni election command (preferably on the switch router that acts as the PGL). The following subset of
election states might indicate possible user correctable conditions if they remain unchanged for an
extended period:
• PGLE Starting—Waiting for the first interface hello state machine to be started on a link. Be sure
that at least one NNI is connected to another switch router (or LGN) and that the hello state machine
on at least one interface is in a state other than down.
• PGLE Awaiting—Waiting for the first interface to reach the hello 2way_in Hierarchical state. It
automatically transitions to the calculating state after waiting for the search peer interval as
displayed by the show atm pnni election command.
• PGLE Awaiting Full, PGLE Initial Delay—Waiting for the first neighbor state machine to reach the
full state and for an initial delay to allow peers to exchange election information. If the election gets
stuck in the awaiting full state, proceed to the “Checking PNNI Neighbor Database
Synchronization” section on page 6-30 to debug neighbor state machine problems.
• PGLE Awaiting Unanimity—This node prefers itself as PGL and is waiting for other nodes to reach
unanimity. It automatically transitions to another state after waiting for the override delay as
displayed by the show atm pnni election command.
• PGLE Hung Election: Not PGL—After waiting for the override delay, less than two-thirds of the
other nodes are advertising it as their preferred PGL. This might result from a change in the topology
or other network parameters. In that case, it should recover by itself. It can also indicate a defective
node or link. Use the show atm pnni election peers command to check for the current connectivity
to other nodes within the same peer group.
• PGLE Awaiting Reelection—The node has lost connectivity to the current PGL. It automatically
transitions to another state after waiting for the re-election interval as displayed with the show atm
pnni election command. Use the show atm pnni election peers command to check for connectivity
to the original PGL and to the other nodes within the same peer group.
• PGLE Operating: Not PGL—The node has lost the election for PGL. To force this node to be the
PGL, reconfigure the election priority to a value higher than the current PGL as listed with the show
atm pnni election command, or else lower the election priority of the current PGL.
For other PGL election problems not isolated by these steps, use the debug atm pnni election command
to turn on debugging messages that show the election events and state changes leading up to the election
outcome as well as some additional election error conditions.
Turn off debugging messages with the no debug all command.