WCCP mode allows only a single appliance in a WCCP service group. If a new appliance attempts to contact the router, it discovers that the other appliance is handling the service group, and the new appliance sets an Alert. It periodically checks to determine whether the service group is still active with the other appliance, and the new appliance handles the service group when the other appliance becomes inactive.
Note: WCCP clustering allows multiple appliances per service group.
Limitations and Best Practices
Following are limitations and best practices for (non-clustered) WCCP mode:
- On appliances with more than one accelerated pair, all the traffic for a given WCCP service group must arrive on the same accelerated pair.
- Do not mix inline and WCCP traffic on the same appliance. The appliance does not enforce this guideline, but violating it can cause difficulties with acceleration. (WCCP and virtual inline modes can be mixed, but only if the WCCP and virtual inline traffic are coming from different routers.)
- For sites with a single WAN router, use WCCP whenever inline mode is not practical.
- Only one appliance is supported per service group. If more than one appliance attempts to connect to the same router with the same service group, the negotiation will succeed only for the first appliance.
- For sites with multiple WAN routers serviced by the same appliance, WCCP can be used to support one, some, or all of your WAN routers. Other routers can use virtual inline mode.