Nortel 4524GT Configuration page 27

Actions
Update 802.1p user priority
Set drop precedence
The Nortel Ethernet Routing Switch 4500 Series filters collectively direct
the system to initiate the following actions on a packet, depending on the
configuration:
•
•
The 802.1p user priority value, used for out-of-profile packets, is derived from
the associated in-profile action to prevent reordering at egress of packets from
a single flow.
Packets received on an interface are matched against all policies associated
with that interface. So, potentially, any number of policies--from none to
many--are applied to the packet, depending on the policies associated with
the specific interface. The set of actions applied to the packet is a result of
the policies associated with that interface, ranging from no actions to many
actions.
For example, if one policy associated with the specific interface specifies
only a value updating the DSCP value, while another policy associated
with that same interface specifies only a value for updating the 802.1p user
priority value, both of these actions occur. If conflicts among actions are
detected--for example, if two policies on the specified interface request that
the DSCP be updated, but specify different values--the value from the policy
with the higher precedence is used.
The actions applied to packets include those actions defined from
user-defined policies and those actions defined from system default policies.
The user-defined actions always carry higher precedences than the system
default actions. This means that, if user-defined policies do not specify
actions that overlap with the actions associated with system default policies
(for example, the DSCP and 802.1p update actions installed on untrusted
interfaces), the default policy actions with the lowest precedence will be
included in the set of actions to be applied to the identified traffic.
Copyright © 2007, Nortel Networks
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Drop
Re-mark the packet
— Re-mark a new DiffServ Codepoint (DSCP)
— Re-mark the 802.1p field
— Assign a drop precedence
Nortel Ethernet Routing Switch 4500 Series
Configuration — Quality of Service
NN47205-504 (322816-B)
5.1 23 November 2007
In-Profile
X
X
ATTENTION
03.01 Standard
Specifying actions 27
Out-Of-Profile
X