Juniper Networks EX2500 - Manual (Page 68)

EX2500 Ethernet Switch Configuration Guide
54 „ Using ACL Filters
Figure 11: QoS Model
The basic QoS model works as follows:
„ Classify traffic:
„ Read the DSCP value.
„ Read the 802.1p priority value.
„ Match ACL filter parameters.
„ Perform actions:
„ Permit packets.
„ Deny packets.
„ Map the 802.1p priority to a COS queue.
„ Map the DSCP to a COS queue.
„ Set the number of COS queues (1 through 8).
„ Queue and schedule traffic:
„ Place packets in one of the COS queues.
„ Schedule transmission based on the COS queue.
Using ACL Filters
Access Control Lists (ACLs) are filters that allow you to classify data packets
according to a particular content in the packet header, such as the source address,
destination address, source port number, destination port number, and others.
Packet classifiers identify flows for more processing. Each filter defines the
conditions that must match for inclusion in the filter, and also the actions that are
performed when a match is made.
ACLs are used to control whether packets are forwarded or blocked at the switch
ports. ACLs can provide basic security for access to the network. For example, you
can use an ACL to permit one host to access a part of the network, and deny
another host access to the same area.
Ports
ACL
Filter
Permit/Deny
Classify
Packets
Perform
Actions
Egress
Ingress
COS
Queue
Queue and
Schedule