GigaSMART Application Session Filtering (ASF) and Buffer ASF

Required Licenses: Adaptive Packet Filtering (APF) and Application Session Filtering (ASF)
NOTE: The ASF license requires the APF license to be installed as a prerequisite.

Deprecation Announcement: GigaSMART Application Session Filtering is end-of-sale in 5.6.00. Refer to the Application Intelligence to learn about the feature set and licensing for the improved application filtering and application metadata functionality.

Application Session Filtering (ASF) provides additional filtering on top of Adaptive Packet Filtering (APF). With APF, you can filter on any data patterns within a packet. With ASF, you apply the pattern matching and then send all the packet flows associated with the matched packet to monitoring or security tools.

ASF allows you to filter all traffic corresponding to a session. Use ASF to create a flow session and send the packets associated with the flow session to one or more tools. A flow session consists of one or more fields that you select to define the session. Either the packets for the whole session can be captured or only the packets following a pattern match.

A flow session is a session defined by protocol fields in the packet. For example, you can define a flow session with source and destination IP (two tuple), source and destination IP plus source and destination port (four tuple), or any combinations with inner or outer IP/port and protocol.

For example, use APF to filter TCP packets to capture the SYN packet. Then use ASF with GigaSMART Load Balancing to send all subsequent packets associated with the session to multiple tool ports. This example is illustrated in Example 1: ASF, Forward TCP Traffic. For information on capturing a whole session by buffering packets, refer to Application Session Filtering with Buffering.

Or use APF to create pattern-matching filters in which the pattern is a sequence of data bytes at a variable or fixed offset within a packet. Then use ASF with a specified session definition to capture subsequent packets belonging to the session. When an incoming packet matches an APF rule, a flow session is created. The subsequent incoming packets that match the value of the fields in the flow session will be forwarded to the same tool port as the matching packet.

For example, use APF to pattern match the string Use the 5tuple field to identify the flow session. This creates the signature of the session. All the packets associated with the session will be forwarded to a tool port, hence APF becomes flow-aware or session-aware.

ASF provides the following session capabilities:

■   filter on one, two, or both MPLS labels and/or VLAN IDs
■   filter on both inner and outer IP addresses, Layer 4 ports, and protocols

Pattern matching examples are illustrated in Pattern Match with Type String to Example 4: ASF, Forward GTP Traffic

For information on load balancing, refer to stateful load balancing in the section GigaSMART Load Balancing.

ASF operations can be assigned to GigaSMART groups consisting of multiple engine ports. Refer to Groups of GigaSMART Engine Ports for details.

In ASF and buffer ASF second level maps, a maximum of five (5) maps can be attached to a virtual port (vport). Each map can contain up to 25 gsrules.

Application Session Filtering (with or without buffering) is a pillar of the GigaSECURE Security Delivery Platform. Refer to GigaSECURE Security Delivery Platform.