24
Chapter 1 An Introduction to Policy-Enabled Networks
Layer 2 classifier elements
The Nortel Ethernet Routing Switch 4500 Series classifies packets based
on the following parameters in the Layer 2 header:
•
source MAC address/mask
•
destination MAC address/mask
•
VLAN ID number (range of)
•
VLAN tag
•
EtherType
•
IEEE 802.1p user priority values
ATTENTION
Layer 2 classifier elements with an Ethernet Type of 0x0800 are treated as an
IPv4 classifier, and those with an Ethernet Type of 0x86DD are treated as an
IPv6 classifier.
System classifier elements
System classifier elements support pattern matching, also referred to as
offset filtering. Offset filtering identifies fields within protocol headers, or
portions thereof, on which to identify traffic for additional QoS processing.
This eliminates the limitations that arise by supporting only certain protocol
header fields, such as IP source address, IP protocol field, and VLAN ID
for flow classification.
Fully customized classifiers can be created to match non-IP-based traffic,
as well as to identify IP-based traffic using non-typical fields in Layers 2, 3,
4, and beyond.
The Nortel Ethernet Routing Switch 4500 Series Content Aware Processor
(CAE) lookup engine supports selection of 16 bytes within the first 128
bytes of the packet.
Classifiers and classifier blocks
Classifier elements can be combined into classifiers, and grouped into
classifier blocks. Classifiers are created by referencing an L2 classifier
element, IP element, a system classifier element, or one of each type.
Each classifier can have a maximum of a single IP classifier element, one
L2 classifier element, one system classifier element or any combination of
one IP, L2 and system classifier element.
Classifiers can be combined into classifier blocks. Each classifier block
has one or more classifiers.
Nortel Ethernet Routing Switch 4500 Series
Configuration — Quality of Service
NN47205-504 (322816-
B
)
03.01
Standard
5.1
23 November 2007
Copyright © 2007, Nortel Networks
.