TDF Gateway Service PICs and Session PICs for Subscriber-Aware Traffic Treatment
You must configure at least one TDF gateway, one service PIC, and one session PIC to operate subscriber-aware traffic treatment. Each service PIC and session PIC is configured on an MS-MPC, and assigned to a TDF gateway.
TDF Gateway
The traffic detection function (TDF) gateway on the MX Series router establishes a context and framework for configuring subscriber-aware services. You assign service PICs and session PICs to the TDF gateway, and specify the call admission control (CAC) parameters for subscriber sessions.
Service and Session PICs
A service PIC provides subscriber-aware policy enforcement and traffic redirection (steering) that is application-aware. Traffic steering refers to the capability to direct or traverse traffic from a specified source to an endpoint or the adjacent network element in a routing path. The service PIC is configured with software plugins to perform the configured or requested services, which include the policy and charging enforcement function (PCEF), application detection and control, HTTP header enrichment, HTTP redirect, and network address translation.
The service PIC also stores the policy and charging control (PCC) rules that it enforces, and holds the subscriber records and rules that are sent from the session PIC.
The subscriber’s assigned TDF logical interface (mif) and the service set that is applied to the mif determine the service PIC to which a packet is sent. See IP-Based Subscriber Setup Overview.
A session PIC supports access subscriber session setup and management, enabling the steering of subscriber traffic to the correct services PIC. The session PIC also sets up a session with the policy and charging rules function (PCRF) so it can receive subscriber PCC rules from the PCRF and send application-start messages to the PCRF.
Figure 1 shows an overview of a service PIC and a session PIC and their functions.
Redundancy for Service PICs and Session PICs
You can configure a service PIC or a session PIC as an individual PIC or with a backup for redundancy. You can configure redundancy by including the interfaces for the primary and the backup PICs in an aggregated multiservices (AMS) interface .
You can configure a session PIC with 1:1 redundancy — a primary session PIC has one backup PIC that does not back up any other session PICs.
You can configure service PICs with N:1 redundancy — multiple service PICs can share the same backup MS-PIC.
In addition to the redundancy configuration, each PIC that is
a primary or backup needs to be configured as a session PIC or service
PIC at the [edit unified-edge gateways tdf gateway-name system] hierarchy level.