Expand Configuration and Management Manual (G06.24+)

Troubleshooting
Expand Configuration and Management Manual—523347-008
21-35
Network Congestion
Network Congestion
Slow response time indicate network congestion, which can be caused by the following
conditions:
•
Too much traffic for the current network capacity.
•
A node or nodes that are fully operational but unable to process the traffic, causing
bottlenecks.
•
Peak loading of the network, causing temporary congestion.
•
A downed path causing rerouting of traffic to other nodes (see Path Down on
page 21-36).
•
A link or links down in a path, reducing the net capacity of the path (see Line(s)
Down on page 21-37).
•
High number of errors on a path, reducing its net efficiency (see Slow Response
Time on page 21-33).
The first three items usually point to assumptions that were made about network
capacity, network growth, or processing power, any one or more of which were lower
than required to efficiently operate the network.
For more information about network design and planning, refer to Section 3, Planning a
Network Design and Section 4, Planning for ServerNet Clusters.
Node Not Available
The following symptoms can indicate that a node is unreachable:
•
File-system error 66, 140, 218, or 248 is returned to the application or by the
Expand subsystem SCF INFO PROCESS $NCP, LINESET command.
•
When the Expand subsystem SCF PROBE PROCESS $NCP command is used to
probe the node, it fails (file-system error 250).
Your first attempt at resolving the problem should be at the End-to-End (Layer 4) level
of the Expand line-handler process. To check the Layer 4 connection, use the following
Expand subsystem SCF command to examine the failing node’s routing table:
INFO PROCESS $NCP, NETMAP, TO node-name
An example of an INFO PROCESS, $NCP NETMAP display is shown in Example 21-5
on page 21-9.
If the best-path route is indicated in the INFO PROCESS $NCP, NETMAP display with
a plus sign (+), then the $NCP-to-$NCP connection request is outstanding and the
connection has not yet been established between the selected node and the displayed
node through this path.
Note. If the best-path route is indicated with an asterisk (*), the selected node is connected to
the displayed node through the path (the best-path route).