Understanding Session Characteristics for J Series Services Routers

Sessions are created, based on routing and other classification information, to store information and allocate resources for a flow. Sessions have characteristics, some of which you can change, such as when they terminated. For example, you might want to ensure that a session table is never entirely full to protect against an attacker's attempt to flood the table and thereby prevent legitimate users from starting sessions.

Depending on the protocol and service, a session is programmed with a timeout value. For example, the default timeout for TCP is 30 minutes. The default timeout for UDP is 1 minute. When a flow is terminated, it is marked as invalid, and its timeout is reduced to 10 seconds.

If no traffic uses the session before the service timeout, the session is aged out and freed to a common resource pool for reuse. You can affect the life of a session in the following ways:

The following topics show you how to modify a session's characteristics. For details, see the JUNOS Software CLI Reference.

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