Managing Serviceguard Fifteenth Edition, reprinted May 2008

Understanding Serviceguard Software Components
How the Network Manager Works
Chapter 3102
Whenever a LAN driver reports an error, Serviceguard immediately
declares that the card is bad and performs a local switch, if applicable.
For example, when the card fails to send, Serviceguard will immediately
receive an error notification and it will mark the card as down.
Serviceguard Network Manager also looks at the numerical counts of
packets sent and received on an interface to determine if a card is having
a problem. There are two ways Serviceguard can handle the counts of
packets sent and received. In the cluster configuration file, choose one of
the following values for the NETWORK_FAILURE_DETECTION parameter:
NOTE For a full discussion, see the white paper Serviceguard Network
Manager: Inbound Failure Detection Enhancement at
http://docs.hp.com -> High Availability -> Serviceguard ->
White Papers.
INOUT: When both the inbound and outbound counts stop
incrementing for a certain amount of time, Serviceguard will declare
the card as bad. (Serviceguard calculates the time depending on the
type of LAN card.) Serviceguard will not declare the card as bad if
only the inbound or only the outbound count stops incrementing.
Both must stop. This is the default.
INONLY_OR_INOUT: This option will also declare the card as bad if
both inbound and outbound counts stop incrementing. However, it
will also declare it as bad if only the inbound count stops.
This option is not suitable for all environments. Before choosing it, be
sure these conditions are met:
All bridged nets in the cluster should have more than two
interfaces each.
Each primary interface should have at least one standby
interface, and it should be connected to a standby switch.
The primary switch should be directly connected to its standby.
There should be no single point of failure anywhere on all
bridged nets.