ADTRAN AOS Version R10.1.0 Command Reference Manual page 2621

Command Reference Guide Tunnel Interface Command Set
Technology Review
The RapidRoute system goal is to increase IP packet throughput by moving as much of the packet
processing into the engine as possible. Packets are classified into flows based upon the IP protocol
(Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Internet Control Message Protocol
(ICMP), etc.), the source and destination IP addresses, IP type of service (ToS), and the protocol-specific
information, such as the source and destination port numbers. Flows are defined as the unidirectional
representation of a conversation between two IP hosts. Each ingress interface keeps its own flow table, a
collection of flow entries.
The first packet in a flow that is forwarded through the unit will build a flow entry. When a flow entry is
looked up but no entry is found, a RapidRouteBuilder object is allocated and attached to the packet. As the
packet passes through the various processing layers, each subsystem will add processing to the
RapidRouteBuilder. When the packet is about to be forwarded out of the egress interface, the
RapidRouteBuilder will be finalized. That is, the flow entry being built will be checked for completeness and
committed to the flow table on the ingress interface. Subsequent flow matches can then bypass the normal
processing layers.
60000CRG0-35E Copyright © 2012 ADTRAN, Inc. 2621