Managing Serviceguard Nineteenth Edition, Reprinted June 2011

The following constraints apply to peer polling when there are only two interfaces on a subnet:
• If one interface fails, both interfaces and the entire subnet will be marked down on each node,
unless Local Switching (page 66) is configured and there is a working standby.
• If the node that has one of the interfaces goes down, the subnet on the other node will be
marked down.
Reporting Link-Level and IP-Level Failures
Serviceguard detects both link-level and IP-level failures; see “Monitoring LAN Interfaces and
Detecting Failure: Link Level” (page 66) and “Monitoring LAN Interfaces and Detecting Failure: IP
Level” (page 70) for information about each level of monitoring. Any given failure may occur at
the link level or the IP level. In addition, local switching may occur, that is, a switch to a standby
LAN card if one has been configured; see “Local Switching ” (page 66).
The following examples show when and how a link-level failure is differentiated from an IP-level
failure in the output of cmviewcl (1m).
As you can see, if local switching is configured, the difference is the keyword disabled, which
appears in the tabular output, and is set to true in the line output, if the IP Monitor detects the
failure. If local switching is not configured, the output is the same whether link-level or IP monitoring
detects the failure.
Example 1: If Local Switching is Configured
If local switching is configured and a failure is detected by link-level monitoring, output from
cmviewcl -v will look like something like this:
Network_Parameters:
INTERFACE STATUS PATH NAME
PRIMARY down (Link and IP) 0/3/1/0 lan2
PRIMARY up 0/5/1/0 lan3
cmviewcl -v -f line will report the same failure like this:
node:gary|interface:lan2|status=down
node:gary|interface:lan2|local_switch_peer=lan1
node:gary|interface:lan2|disabled=false
node:gary|interface:lan2|failure_type=link+ip
But if the IP Monitor detects the failure (and link-level monitoring does not) cmviewcl -v output
will look something like this:
Network_Parameters:
INTERFACE STATUS PATH NAME
PRIMARY down (disabled) (IP only) 0/3/1/0 lan2
PRIMARY up 0/5/1/0 lan3
cmviewcl -v -f line will report the same failure like this:
node:gary|interface:lan2|status=down
node:gary|interface:lan2|local_switch_peer=lan1
node:gary|interface:lan2|disabled=true
node:gary|interface:lan2|failure_type=ip_only
In this case, you would need to re-enable the primary interface on each node after the link is
repaired, using cmmodnet (1m); for example:
cmmodnet —e lan2
Example 2: If There Is No Local Switching
If local switching is not configured and a failure is detected by link-level monitoring, output from
cmviewcl -v will look like something like this:
Network_Parameters:
INTERFACE STATUS PATH NAME
How the Network Manager Works 73