Maintenance Mode Overview for Subscriber Aware Policy Enforcement
With Junos OS maintenance mode, you can take certain network functionality offline to perform specific maintenance tasks without disrupting service. When the traffic detection function (TDF) domains, TDF gateways, TDF subscribers, TDF interfaces, subscriber polices, or service PICs 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 (However, maintenance mode is not required to add PCC rules or rulebases to a dynamic PCEF profile.)
Delete or modify a PCC rule
Delete or modify a PCC rulebase
Delete or modify a Diameter profile
Delete or modify a flow description
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 elements carry no traffic and thus do not need to be gracefully halted. However, you can create new network elements in maintenance mode as an environment in which to test configurations before deploying them.