Proprietary and Confidential to PMC-Sierra, Inc and for its Customers
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Internal Use
Document ID: PMC-2010146, Issue 4
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PM2329 ClassiPI Network Classification Processor Datasheet
1.3 Functional Overview
The PM2329 is designed for use in switches, routers, access concentrators and other telecommunications
equipment such as traffic shapers, firewalls and network address translators. These equipment implement
one or more of software modules in the PM2329, such as the Routing, QoS, NAT, Firewall, Load
Balancing and Network monitoring modules. These modules implement functions such as address lookup,
flow classification, and connections cache identification. The PM2329 accelerates these functions,
extending the performance of such equipment in Gigabit/OC-48 wirespeed environments.
The PM2329 is a high performance search and classification processor. During initialization the external
packet processor and application code will configure the description of various searches that would be
performed by the PM2329. These descriptions consist of key extraction procedures, rule table identities,
search methodologies and termination criteria. The external packet processor will then load the PM2329
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on-chip rule memory with a set of initial rules for every search. These rules can also be updated at a later
time. Once the PM2329 has been configured, the external packet processor can submit packet data together
with classification requests. Classification requests can trigger multiple searches to be performed on the
same packet. Multiple searches are typically useful when multiple applications are supported on the
network equipment - such as routing, QoS, NAT etc. For example, a route lookup table can be stored in one
table, while another table can store a QoS flow classification policy. The searches can be specified to be
conditional upon the results of the previous searches. The ability to partition the rule memory combined
with the ability to sequence multiple searches enable the system designer to offload complex packet
processing tasks to the PM2329.
The PM2329 returns a series of results for every packet it analyzes. These can be used by software either
directly or to index into a user data structure. The PM2329 provides the capability of attaching an external
SRAM, which can store user programmable data corresponding to the indexes returned upon a match. In
addition to searches, the PM2329 can gather statistics--counts and time stamps--against every rule match.
The PM2329 gathers these statistics in the external SRAM.
Before performing a search operation on a packet, the PM2329 performs key extraction. The PM2329 has
an on-chip Field Extraction Engine that can extract Layer 3 and Layer 4 header fields from IPv4 packets as
the packet data is presented to the chip. Using these fields, it constructs a header key that be used during
searches. Further, it can also extract keys (short and long) at arbitrary offsets into the input data stream.
Each extracted key is made up of a number of fields. Every rule in the rule tables specifies values and
conditions for all fields in a key.
The PM2329 search engine can perform tasks such as:
Single or multiple match identification
Prioritized match selection on multiple match
Layer-N searches: patterns and signature composed of strings, numbers, etc.
Longest prefix (LP) search for IP Routing