WCCP service groups, service numbers, service IDs and well known services
A FortiGate unit configured as a WCCP server or client can include multiple server or client configurations. Each of these configurations is called a WCCP service group. A service group consists of one or more WCCP servers (or routers) and one or more WCCP clients working together to cache a specific type of traffic. The service group configuration includes information about the type of traffic to be cached, the addresses of the WCCP clients and servers and other information about the service.
A service group is identified with a numeric WCCP service ID (or service number) in the range 0 to 255. All of the servers and clients in the same WCCP service group must have service group configurations with the same WCCP service ID.
The value of the service ID provides some information about the type of traffic to be cached by the service group. Service IDs in the range 0 to 50 are reserved for well known services. A well known service is any service that is defined by the WCCP standard as being well known. Since the service is well known, just the service ID is required to identify the traffic to be cached.
Even though the well known service ID range is 0 to 50, at this time only one well known service has been defined. Its service ID 0, which is used for caching HTTP (web) traffic.
So to configure WCCP to cache HTTP sessions you can add a service group to the WCCP router and WCCP clients with a service ID of 0. No other information about the type of traffic to cache needs to be added to the service group.
Since service IDs 1 to 50 are reserved for well know services and since these services are not defined yet, you should not add service groups with IDs in the range 1 to 50.
| FortiOS does allow you to add service groups with IDs between 1 and 50. Since these service groups have not been assigned well known services; however, they will not cache any sessions. Service groups with IDs 51 to 255 allow you to set the port numbers and protocol number of the traffic to be cached. So you can use service groups with IDs 51 to 255 to cache different kinds of traffic based on port numbers and protocol number of the traffic. Service groups 1 to 50; however, do not allow you to set port numbers or protocol numbers so cannot be used to cache any traffic. |
To cache traffic other than HTTP traffic you must add service groups with IDs in the range 51 to 255. These service group configurations must include the port numbers and protocol number of the traffic to be cached. It is the port and protocol number configuration in the service group that determines what traffic will be cached by WCCP.