Nortel Web OS 10.0, Application Manual

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Web OS 10.0 Application Guide
Chapter 10: Health Checking
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212777-A, February 2002
Link Health Checks
Link health check is performed at the Layer 1 (physical) level. The server is considered to be
up when the link (connection) is present and the server is considered to be down when the link
is absent. These checks are used on servers that do not respond to any other health checks.
Intrusion Detection Servers (IDSs) fall into this category. Many IDSs have two physical
interfaces. One is used to detect intrusions, and the other is used to generate logging. The first
interface detects intrusions but it does not have TCP/IP stack. So it is not possible to perform
any health check other than Layer 1 health checking on the IDS. As long as the physical link
between the switch and the IDS is up, it indicates the IDS is alive.
To perform this health check, a link option has been added to the real server group health com-
mand. The real server number is used to determine which port the server is connected to. For
example, real server 1 is assumed to be connected to port 1. The valid IDS real server numbers
are from 1 to 9 when health check is in use.
Configuring the Switch for Link Health Checks
Configure the switch to verify if the IDS server is alive by performing the following tasks:
1. Select the health check menu for real server group 1.
2. Set the health check type to
link
for real server group 1.
3. Apply and save your configuration.
>> # /cfg/slb/group 1
>> # Real server group 1# health
Current health check type: tcp
Enter health check type: link
>> # Real server group 1# apply
>> # Real server group 1# save