12-42
Cisco SCE 2000 and SCE 1000 Software Configuration Guide
OL-7827-12
Chapter 12 Value Added Services (VAS) Traffic Forwarding
VAS over 10G
How to Configure the Minimum Time between Link Switches
• Options, page 12-42
• How to Configure the Delay between Link Switches, page 12-42
• How to Revert to the Default Delay Configuration, page 12-42
You can configure the minimum time allowed between two consecutive link switches. This parameter
applies only after a link switch and before any health check has succeeded.
Note that the system assumes the servers are UP while the health check initializes (initialization occurs
as a result of every change in the configuration related to the health check or after a link switch, and it
lasts until the first health check success or failure). This means that even if the servers are actually
DOWN or not even connected, it is assumed that they are UP and user traffic is forwarded to them. Once
the health check fails, the servers are declared to be Down, and user traffic is no longer forwarded to
them.
In VAS over 10G topology, the default delay between two consecutive link switches (30 seconds) is less
than the time it takes for the health check to fail. This means that once a VAS server group fails, the SCE
platform switches immediately to the second link.
In cases where there is at least one failed VAS server group on both links, the SCE platform will flip
continuously between the links, and as described above, most of this time the state of the servers will be
UP.
To avoid the constant flip between the links in such a case, it is recommended to configure a
link-switch-delay time greater than 3 minutes.
It is also recommended to monitor the SNMP traps conveying messages on changes in server status.
Options
The following option is available:
• switch-time — The time in seconds to hold between two consecutive link switches on initial health
check state.
–
Default = 30 seconds
How to Configure the Delay between Link Switches
Step 1 From the SCE(config if)# prompt, type VAS-traffic-forwarding traffic-link auto-select
link-switch-delay switch-time and press Enter.
How to Revert to the Default Delay Configuration
Step 1 From the SCE(config if)# prompt, type no VAS-traffic-forwarding traffic-link auto-select
link-switch-delay and press Enter.
You can also use the default form of the command:
default VAS-traffic-forwarding traffic-link auto-select link-switch-delay
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