Avaya Cajun P882 User Manual page 313

Configuring IP Routing
the Ports are only valid if TCP or UDP is the selected protocol
and can be expressed as a single port or range of ports. The
protocol ID for TCP and UDP is 6 and 17 respectively.
Access List/Access Control List (ACL): an ordered list of ACL
Rules.
ACL Rule: An element of an ACL that identifies traffic based
upon a 5-tuple (condition), and specifies a queue (0-7), permit,
or deny action for packets matching the condition.
CPU: The general processor for the P580/P882 that resides on
the Supervisor module. The CPU determines whether to
forward or filter packets. It identifies Flows by resolving IP-to-
MAC addressing and matching ACL Rules. It updates the F-
chip's forwarding cache for future Fast Path'ing of packets that
match this Flow. The process of examining Flows and updating
all of the F-chips' forwarding caches is called Slow Path.
DA: Destination IP Address.
F-chip: Forwarding-chip (F-chip) is an application specific
integrated circuit (ASIC) that forwards recognized packets via
Fast Path or unrecognized packets via Slow Path. It learns or
flushes L3 forwarding entries (L3FE) as directed by the CPU. In
earlier versions of the hardware, the F-Chip was referred to as
the Packet Routing Engine (PRE).
Fast Path: When an F-chip is able to recognize and forward a
packet to the destination port without CPU intervention. Both
FIRE (media modules) and FORE (supervisor module) are Fast
Path forwarding mechanisms.
FIRE (Fast In-Band Routing Engine): When an 80-series
Ethernet media module has been licensed for routing, the F-
Chips on that module provide fast, direct forwarding of L3
packets to their destination ports. The destination ports can be
on the same module or a different module.
Flow: A set of routed packets that get the same Layer 3
Forwarding Entry (L3FE) due to equivalent address
characteristics. The complexity of this equivalence will affect the
frequency that packets match a single Flow. In the simplest
case, such as no ACL present, a Flow is identified only by the
destination address of the packet, for a high rate of L3FE re-use.
In the most complex case, such as an ACL that specifies the
entire 5-tuple, the granularity of identification will cause a very
low rate of re-use.
Avaya P550R, P580, P880, and P882 Multiservice Switch User Guide, v5.3.1 9-31