Size Limit For Ip And Ipv6 Cam Hardware Classifiers - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - POLICY MANAGEMENT CONFIGURATION GUIDE 2010-10-04 Configuration Manual

Size Limit for IP and IPv6 CAM Hardware Classifiers

Copyright © 2010, Juniper Networks, Inc.
host1(config-policy-list-classifier-group)#exit
host1(config-policy-list)#classifier-group *
host1(config-policy-list-classifier-group)#filter
host1(config-policy-list-classifier-group)#exit
host1(config-policy-list)#exit
A single classifier entry consumes more than one CAM entry when:
A classifier entry contains a port range. For example:
host1(config)#ip classifier-list clacl3 tcp any any range 5 8
A classifier entry contains the not keyword. Although this keyword is supported for IP
classifier lists, we recommend that you not use it—you can usually achieve the desired
behavior without this keyword.
host1(config)#ip classifier-list clacl4 ip not host 1.1.1.1 any
In these cases, the actual number of entries that are consumed depends on the
configuration.
In JunosE Release 10.1.x and lower-numbered releases, the maximum width of a CAM
hardware classifier entry for IPv4 or IPv6 in a single policy was 128 bits. This limitation
enabled only 128 bits of classification data to be supported per policy. Any policy
configuration (sum of all CLACL entries) with more than 128 bits of classification data
failed when a policy was attached to an interface. This 128-bit size limitation applied to
both IPv4 and IPv6 classification data. Although this limitation was acceptable for IPv4
classification, it posed problems when full IPv6 classification was required to be
performed. In JunosE Release 10.2.x and later, based on the size limit for a combined IPv6
classifier entry, a maximum of 336 bits of CAM entry is supported for full IPv6
classification.
Some independent classifiers share the same classifier entry location, while others are
combined together to form a larger classifier field. The smallest IPv6 classifier can
consume 8 bits and the largest IPv6 classifier can consume 336 bits. Beginning with
JunosE Release 10.2.x, variable-sized CAM entries are supported for IPv6 policies to avoid
wasteful use of CAM entries. In earlier releases, the number of CAM entries per line module
was predefined because all CAM entries were of a fixed size of 128 bits. With the support
for variable-sized CAM entries for IPv6 policies, a dynamic algorithm is used for CAM
resource management. This feature is supported on GE-2 and GE-HDE line modules on
ERX14xx models, ERX7xx models, and the ERX310 router and ES2 4G LMs on E120 and
E320 routers.
NOTE: OC48/STM16 line modules on ERX14xx models, ERX7xx models, and
the ERX310 router support only 128-bit IPv6 classification.
Based on the size limit for a combined IPv6 classifier entry, a maximum of 336 bits of
CAM entry is supported for full IPv6 classification. An additional 16 bits that are reserved
for rule set ID are added to the total classifier entry size, which causes the total CAM
Chapter 8: Policy Resources
155