Variable-Sized Cam Classification For Ipv6 Policies Examples; Table 24: Classification Fields For Example 2 - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - POLICY MANAGEMENT CONFIGURATION GUIDE 2010-10-04 Configuration Manual

JunosE 11.3.x Policy Management Configuration Guide

Variable-Sized CAM Classification for IPv6 Policies Examples

162
Apply the policy list to an interface.
6.
host1(config)#interface atm 5/0/0.1
host1(config-if)#ip policy input ipPol
% too many classifier fields in policy
Table 24 on page 162 lists the active classifiers in the policy named ipPol and the size
of each classifier.

Table 24: Classification Fields for Example 2

Classifiers
Source address
Source port
Destination port
Protocol
User packet class
Color
IP fragmentation
ToS
The configuration fails because the total value of the classifiers requested in the ipPol
policy is 136, which is greater than 128 bit CAM entry size limit.
Variable-sized CAM entries are supported for IPv6 policies to avoid wasting memory
space. For example, if the classifier entries in a policy consume a 576-bit CAM entry when
a 144-bit CAM entry is sufficient to store the classifier, over 400 bits of CAM memory are
wasted. CAM memory is divided into blocks at the hardware level. Each CAM block can
support 8000 144-bit, 4000 288-bit, or 2000 576-bit CAM entries. Based on the IPv6
header CAM entry size calculation, the minimum entry size required for IPv6 classification
is 8 bits and the maximum entry size required is 336 bits.
Policy Manager calculates the CAM bit size and configures the CAM entries on the line
modules. The size of the CAM entry is determined using the limits defined for each of the
IP classifier entry combination. In earlier releases, any policy configuration with CAM
entries that exceeded the 128-bit limitation failed to be attached to the interface because
it was not allowed by Policy Manager.
Beginning with JunosE Release 10.2.x, the IPv6 classification functionality is modified to
classify traffic on more than 128 bits. To improve scalability for IPv6 policies, Policy
Manager uses the optimum CAM entry size, depending on the IPv6 policy definition. The
policy definition of IPv6 is used to determine which classification fields in the combined
Size (Bits)
32
16
16
8
8
8
8
8
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