Nortel Networks WEB OS 212777 - Manual (Page 222)

Web OS 10.0 Application Guide
222 n Chapter 10: Health Checking
212777-A, February 2002
DSR Health Checks
Direct Server Return (DSR) health checks are used to verify the existence of a server-provided
service where the server replies directly back to the client without responding through the vir-
tual server IP address. In this configuration, the server will be configured with a real server IP
address and virtual server IP address. The virtual server IP address is configured to be the same
address as the user’s virtual server IP address. When DSR health checks are selected, the spec-
ified health check is sent originating from one of the switch’s configured IP interfaces, and is
destined to the virtual server IP address with the MAC address that was acquired from the real
server IP address’s Address Resolution Protocol (ARP) entry.
Web OS 10.0 allows you to perform health checks for DSR configurations. For more informa-
tion, see
“Using Direct Server Return” on page 142 . The switch is able to verify that the server
correctly responds to requests made to the virtual server IP address as required in DSR config-
urations. To perform this function, the real server IP address is replaced with the virtual server
IP address in the health check packets that are forwarded to the real servers for health check-
ing. With this feature enabled, the health check will fail if the real server is not properly config-
ured with the virtual server IP address.
N OTE – viphlth is enabled by default. This has no effect on the health check unless the real
server is configured with DSR.
Configuring the Switch for DSR Health Checks
1. Select the health check menu for a real server group.
2. Enable DSR VIP health checks for a real server group.
For more information on DSR, see “Using Direct Server Return” on page 142 .
3. Apply and save your configuration.
>> # /cfg/slb/group 1 (Select the Real Server Group 1 menu)
>> Real server group 1# viphlth enable|disable
>> DSR VIP Health Check# apply