Troubleshooting guide

6-26
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 6 Troubleshooting Switch Router ATM Network Connections
Troubleshooting SVC Connections on a PNNI Routing Network
If the prefix appears correctly on the terminating node, continue to the following section, “Checking
PNNI Topology.”
Checking PNNI Topology
The show atm pnni topology command and show atm pnni election peers command display the actual
topology of connected switch router nodes that the originating node (RemFl1Ls1 in this example) has
learned. Confirm that an unbroken path of nodes and links with the status up can be found between the
originating and terminating switch routers (or for hierarchy, to a terminating end ancestor LGN).
Use the following commands to examine the node PNNI topology and switch router connectivity:
Follow these steps to display the actual topology of the connected nodes that the originating switch
router has learned:
Step 1 Use the show atm pnni topology command to display the actual topology of the connected switch router
nodes.
Step 2 If the terminating node is not shown or if necessary links are down or missing for an unbroken path,
it indicates that the originating switch router (RemDvLs1 in this example) cannot find a path to the
terminating node. Either a physical problem exists at the indicated network failure location, or else PNNI
is unable to update its database to reflect the actual network condition.
Step 3 Use the show atm pnni election peers command to confirm whether this node has connectivity to any
particular node within the same peer group.
Note Use the show atm pnni identifiers command to determine which nodes are represented by
the node numbers that are internally assigned.
If a peer node is missing or is shown as NO for the Connected column, then PNNI considers that there
is no path to that node.
Step 4 Check for physical problems by executing the show atm pnni interface command on the indicated
failing nodes. If no physical problems are shown for the indicated failing nodes, proceed to the
“Troubleshooting the PNNI Database” section on page 6-30.
If an unbroken path does exist based on the topology display, but debugging the PNNI routing showed
that the destination was not initially PNNI_SUCCESS, it might mean that there are routing restrictions
based on QoS, CAC, scope, or other path constraints that could not be met.
Command Purpose
show atm pnni topology Displays the actual topology of the
connected nodes.
show atm pnni election peers Displays the connectivity to a specific
node within a peer group.