Maintenance Mode Overview for Service Control Gateway
With Junos OS maintenance mode for Service Control Gateway, you can take certain network functionality offline to perform specific maintenance tasks without disrupting service. When the traffic detection function (TDF) domains, gateways, subscribers, and the like need maintenance, entering maintenance mode prevents these subscriber services elements from accepting new requests. You have the option of allowing all existing services to complete, or clear them. When ready, you can proceed with critical maintenance functions with a minimum of service disruption. Subscribers who attempt to access a gateway that is in maintenance mode receive a message that the service is not supported.
If you want to perform any of the following operations, you must do so in maintenance mode:
Delete or modify the addresses of certain TDF (mif) interfaces.
Delete or change the type of a TDF domain.
Change TDF interface configuration parameters.
Change a TDF interface for a TDF domain.
Change a static time-of-day profile.
Delete or modify a policy and charging enforcement function (PCEF) profile.
Delete an address pool or modify its parameters.
You can perform all other maintenance tasks outside of maintenance mode.
The maintenance mode procedures listed do not include adding elements. New gateways, TDF domains, and such carry no traffic and thus do not need to be gracefully halted. However, you can create new Service Control Gateway network elements in maintenance mode as an environment in which to test configurations before deploying them.