Ingress traffic processing through a device – Brocade Multi-Service IronWare QoS and Traffic Management Configuration Guide (Supporting R05.6.00) User Manual
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Multi-Service IronWare QoS and Traffic Management Configuration Guide
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Ingress Traffic processing through a device
4
•
Configuring Packet Drop Priority using WRED – This section describes how to configure
Weighted Random Early Detection (WRED). Refer to
“Configuring packet drop priority using
•
Scheduling Traffic for Forwarding – The Brocade supports six different schemes for prioritizing
traffic for forwarding in a congested network. This section describes each of these schemes
and how to configure them. Refer to
“Scheduling traffic for forwarding”
•
Traffic Manager Statistics Display - Counters have been introduced to track the packets and
bytes that enter the Ingress traffic manager and exit the egress traffic manager. Refer to QoS
for NI-MLX-1Gx48T modules -
“Traffic manager statistics display”
•
QoS for NI-MLX-1Gx48-T modules - The NI-MLX-1Gx48-T module supports 48 1G port. In a fully
loaded 32 slot chassis, there are only 8 queues supported on the TM port. Refer to
•
Aggregated TM VOQ Statistics Collection - Refer to
“Aggregated TM VOQ statistics collection”
•
QoS Commands affected by Priority Queues - Refer to
“QoS commands affected by priority
•
Enhanced Packet Buffering – This section describes how to configure Enhanced Packet
Buffering for prioritizing the buffer pool and VOQ Queue size. This section describes each of
these schemes and how to configure them. Refer to
“Enhanced buffer management for
NI-MLX-10Gx8 modules and NI-X-100Gx2 modules”
Ingress Traffic processing through a device
The QoS operation on Ingress Traffic of a Brocade device involves reception and processing of
packets based upon priority information contained within the packet. As the packets are processed
through the device, there are several opportunities to influence the processing by configuration as
described in the steps below.
1. Derive priority and drop precedence from the packets PCP (IEEE 802.1p) value. The Priority
Code Point (PCP) is a 3-bit field within an IEEE 802.1Q tagged frame that is used to convey the
priority of the frame. By using a mapping table, the 3-bit PCP field can be decoded to derive
priority and drop precedence information.
NOTE
The PCP field was formerly called IEEE 802.1p.
2. Derive priority and drop precedence from the packets EXP value.
3. Derive priority and drop precedence from the packets DSCP value.
NOTE
DSCP encoding and decoding are not supported for MPLS packets.
4. Merge or force the priorities described in steps 1 through 3.
5. Merge or force the priority and drop precedence value based on the value configured for the
physical port.
6. Merge or force the priority value based on the value configured for the VLAN.