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 fast path.
A Flow Aware Packet Acceleration license is required on ASR5500 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 ASR5500 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.
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
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 packets.
This feature 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
The following 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.