Brocade FastIron Ethernet Switch Traffic Management Guide - Manual (Page 23)

one 1-GbE port in the back-end NP. The two network ports share the same hardware queues, and
therefore they have the same buffer and descriptor limits and scheduling algorithm for transmission.
Ingress packets are classified into eight QoS priority levels at the front-end NP of the SX-FI48GPP
module. The eight priorities are mapped into four hardware queues based on the priority queue
configuration in the following table. QoS priority 7 is the highest priority, and QoS 0 is the lowest priority.
Priority queues for the SX-F148GPP TABLE 7
QoS priority level Hardware queues
(traffic classes)
0 0
1 0
2 1
3 1
4 2
5 2
6 3
7 3
QoS classification occurs in two iterations; initially in the front-end NP, followed by the back-end NP.
The back-end NP has the same classification and marking capabilities of existing FastIron SX interface
modules, but the front-end NP does not support ACL and static MAC priority. The front-end NP supports
basic QoS features, such as port priority, QoS-ToS mapping, 802.1p to priority mapping, 802.1p
override, and trust DSCP mode.
The default scheduling configuration for Weighted Round Robin (WRR), Hybrid WRR and Strict Priority
(SP), and SP mode for the eight QoS priority queues mapped to the four hardware queues is described
under
Default scheduling configuration for the SX-FI48GPP module on page 36.
Queues for the SX-FI-8XG interface module
The SX-FI-8XG interface module consists of two separate hardware Network Processors (NP). The
front-end NP supports 8 hardware queues, and the back-end NP supports eight hardware queues. In
the egress, traffic is destined to four adjacent ports (for example, ports 1/1 to 1/4), and aggregated into
one 10GbE port in the back-end NP. The four network ports share the same hardware queues;
therefore, they have the same buffer and descriptor limits and scheduling algorithm for transmission.
QoS classification occurs in two iterations; initially in the front-end NP, followed by the back-end NP.
The back-end NP has the same classification and marking capabilities of existing FSX interface
modules, however, the front -end NP does not support ACL and static MAC priority. The front-end NP
supports basic QoS features, such as port priority, qos-tos mapping, 802.1p to priority mapping, 802.1p
override, and trust-dscp mode.
Queues for the SX-FI-8XG interface module
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