HP Serviceguard A.11.20- Managing Serviceguard Twentieth Edition, August 2011

NETWORK_POLLING_INTERVAL, the IP monitor will detect the recovery of an IP address typically
within 8–10 seconds for Ethernet and with 16–18 seconds for InfiniBand.
IMPORTANT: HP strongly recommends that you do not change the default
NETWORK_POLLING_INTERVAL value of 2 seconds.
See also “Reporting Link-Level and IP-Level Failures” (page 76).
Constraints and Limitations
• A subnet must be configured into the cluster in order to be monitored.
• Polling targets are not detected beyond the first-level router.
• Polling targets must accept and respond to ICMP (or ICMPv6) ECHO messages.
• A peer IP on the same subnet should not be a polling target because a node can always ping
itself.
• On an HP-UX system, an IP-level failure on the standby interface will not be detected until the
IP address fails over to the standby.
• On an HP-UX system, after the IP address fails over to the standby, the IP monitor will not
detect recovery on the primary interface.
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 70) 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 69) and “Monitoring LAN Interfaces and Detecting Failure: IP
Level” (page 73) 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 70).
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
76 Understanding Serviceguard Software Components