Priority Mapping With And Without Qos Pass-Through Mode; How To Enable/Disable Qos Pass-Through Mode - ProCurve 2626 Management And Configuration Manual

Port Status and Basic Configuration
QoS Pass-Through Mode on the Series 2800 and 4100gl Switches
10-26
Any 802.1p tagging on a received packet, or any tag added to a
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received frame by the switch via its QoS configuration, will be
preserved as it is transmitted from the switch.
NOTE: As stated earlier, use of this QoS-Passthrough-Mode feature
generally assumes that QoS tagged packets are not being sent through
the switch. The receipt of priority 6 or 7 packets may in fact suffer
packet drops depending on the traffic load of non-priority 6 or 7
packets.

Priority Mapping With and Without QoS Pass-Through Mode

The switch supports 802.1p VLAN tagging, which is used in conjunction with
the outbound port priority queues to prioritize outbound traffic.
An 802.1Q VLAN tagged packet carries an 802.1p priority setting (0-7). If the
switch receives a tagged packet, it is placed into the appropriate queue based
on the frame's 802.1p priority setting. The mapping with/without QoS Pass-
Through Mode is as follows:
802.1p Priority Prioritization Queue Placement
Setting
Default QoS
Setting
1 1 (low)
2 1 (low)
0 or 2 (normal)
Unspecified
3 2 (normal)
4 3 (medium)
5 3 (medium)
6 4 (high)
7 4 (high)

How to enable/disable QoS Pass-Through Mode

QoS Pass-Through Mode is disabled by default, and is available only in I.07.52
and later switch software versions.
QoS Passthrough
Mode
2 (normal)
2 (normal)
2 (normal)
2 (normal)
2 (normal)
2 (normal)
4 (high)
4 (high)