HP ProCurve 5300xl Series Management Manual page 286

Quality of Service (QoS): Managing Bandwidth More Effectively
Introduction
Precedence Criteria
4 Layer 3
Protocol
Priority
If a packet does not meet the criteria for Protocol priority, then precedence defaults to the VLAN classifier,
below.
5 VLAN
Priority
If a packet does not meet the criteria for VLAN priority, then precedence defaults to the Source-Port
classifier, below.
6 Source-
Port
If a packet does not meet the criteria for source-port priority, then precedence defaults to Incoming 802.1p
criteria, below
7 Incoming
802.1p
Priority
If a packet does not meet the criteria for Incoming 802.1p priority, then the packet goes to the "normal"
outbound queue of the appropriate port. If the packet entered the switch through a port that is an untagged
member of a VLAN, but exits through a VLAN-tagged port, then an 802.1Q field, including an 802.1p priority,
is added to the packet header. If no QoS policy is configured or applied to the packet, then the 802.1p priority
of 0 (normal) is assigned to the packet for outbound transmission.
8-12
Overview
Note: This classifier is available in the 5300xl switches, but not in the 3400cl/6400cl switches.
To prioritize traffic in a 3400cl or 6400cl switch according to protocol type, configure the switch
to place traffic of the desired protocol type in a specific VLAN, and then apply the VLAN
classifier.
Takes precedence based on network protocols: IP, IPX, ARP, DEC LAT, AppleTalk, SNA, and
NetBeui. Default state: No-override for any protocol.
Takes precedence based on the ID number of the VLAN in which the inbound packet exists.
For example, if the default VLAN (VID = 1) and the "Blue" VLAN (with a VID of 20) are both
assigned to a port, and Blue VLAN traffic is more important, you can configure QoS to give Blue
VLAN traffic a higher priority than default VLAN traffic. (Priority is applied on the outbound
port.) Default state: No-override.
Takes precedence based on the source-port (that is, the port on which the packet entered the
switch).
Where a VLAN-tagged packet enters the switch through a port that is a tagged member of that
VLAN, if QoS is not configured to override the packet's priority setting, the switch uses the
packet's existing 802.1p priority (assigned by an upstream device or application) to determine
which inbound and outbound port queue to use. If there is no QoS policy match on the packet,
and it then leaves the switch through a port that is a tagged member of the VLAN, then there
is no change to its 802.1p priority setting. If the packet leaves the switch through a port that is
an untagged member of the VLAN, the 802.1p priority is dropped.
Entering
(Inbound) 802.1p Queue
Priority
1 - 2
0 - 3
4 - 5
6 - 7
Outbound Port Exiting
(Outbound)
802.1p Priority
Low 1 - 2
Normal 0 - 3
Medium 4 - 5
High 6 - 7