The Flow Aware
Packet Acceleration (FAPA) feature improves the throughput in terms of PPS, by
caching rule matching results of a flow for selected flows so as not to incur
the lookup penalty for a large number of packets in that flow. This new
accelerated path is capable of performing a full range of basic functions
including handling charging, modification of packet headers, and incrementing
various counters. The accelerated path dynamically evaluates the current flow
state and reverts back to the slow path when the flow cannot be handled on the
A Flow Aware
Packet Acceleration license is required on ASR 5500 and VPC platforms.
The acceleration is
applied to specific flows without affecting any external interfaces related to
Billing, CLI, interfaces, and so on. This feature is an extension of the
TRM/FastPath that was introduced in R15.0 for ASR 5500 platform. This feature
will be supported when TRM FastPath is enabled on the Rulebase. TRM FastPath
works on approximately 50-65 of all packets, including VoLTE, Encrypted and
HTTP, in the system for any given call model, with the control path left
intact. New changes are in the data path after TRM has cached the rule matching
results. FAPA ECS packet path can efficiently process 50+ of data packets in
the system, yielding a significant performance gain on ECS data path.
TRM/FP support has
been extended beyond rule-matching. Qualifying packets avoid much of the ECS
stack for N bytes of volume for a given flow. Only the packets requiring
minimal work are qualified for the accelerated path. The work needed for each
packet include a subset of flow actions, QoS enforcement, L3/L4 header
inspection, TCP sequence number validation, and applicable charging methods.
The FAPA function
identifies packets that need only a small amount of processing, and performs
only those necessary tasks on these packets. Only those packets that do not
require DPI are allowed to enter the Accelerated path.
HTTP, HTTPS, RTP and plain TCP/UDP traffic where L7 analysis is not
enabled, and so on are all the flows that will get accelerated.
The FAPA functionality is extended for the active charging
service with CF/ICAP/BL configured. Simple TCP traffic will be eligible on
accelerated path with Static Content Filtering configured in active charging
service but not in rulebase. Packets for tethered flows will be counted on
accelerated packets. Packets for blacklisted flows will be counted on fast-path
provides the operator with additional capacity on deployed systems without any
hardware addition. The operators could get 30-40 of the system capacity based
on their traffic pattern and deployed call models.
charging formats are supported on the FAPA feature, which gives improved
performance for HTTP traffic, if the traffic flow is FAPA eligible:
The FAPA feature is
controlled by the FAPA license, and a CLI at active-charging service. The FAPA
path will be functional, only if TRM/FP is enabled and the CLI is configured.