Ingress Queuing - Cisco Nexus 7000 Series Configuration Manual

Ingress Queuing

• Queue-limit—Amount of buffers to be allocated for a class of service (CoS).
• Bandwidth—Priority grouping and its bandwidth allocation advertised using the Data Center Bridging
• Set CoS—Untrusted port default CoS (similar to the M1 modules).
Egress queuing determines the following attributes:
• Bandwidth—Differential Weighted Round Robin (DWRR) bandwidth for a given queue and the group.
• Priority level—The priority level of the queue.
• Shape—The shaper for the queue.
Ingress Queuing
You use the ingress queuing to partition the port ingress buffers that are 1.25 MB and an additional 256 KB
(a total of 1.5 MB) to absorb the frames in transit after pause has been sent. This buffer is partitioned among
the eight CoS values. The number of partitions is fixed for a given network qos template. The incoming CoS
values are mapped to each partition. Each buffer partition is considered as an ingress queue.
There is a high threshold and a low threshold at which the pause or resume frames are generated when a
threshold is met. This requirement is applicable to the no-drop CoS only. The frames that are in transit are
absorbed by a skid buffer after a pause is generated. If the number of frames exceed the skid buffer threshold,
the frames are tail dropped. There are three thresholds for drop eligible (DE), non-DE, and Bridge Protocol
Data Unit (BPDU) frames for dropping. For the drop CoS, the high and low thresholds are the same.
The default policy ingress queues are created as follows:
• Different queues per drop class:
• Different queues for priority and nonpriority CoS in a given drop class:
Each network qos policy has a corresponding default ingress queuing policy (template) and is automatically
activated for the system. They are the default-4q-8e-in-policy, default-4q-7e-in-policy, default-4q-6e-in-policy,
default-4q-4e-in-policy, default-8e-4q8q-in-policy, default-7e-4q8q-in-policy, default-6e-4q8q-in-policy,
default-4e-4q8q-in-policy, and default-8e-4q4q-in-policy.
The predefined class map names (queue names) for ingress queuing are described in the table below.
Table 34: Predefined Class Maps for Ingress Queuing
Ingress Policy Maps
default-4q-8e-in-policy
default-4q-7e-in-policy
default-4q-6e-in-policy
Cisco Nexus 7000 Series NX-OS Quality of Service Configuration Guide
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Capability Exchange Protocol (DCBXP).
Drop queue =70% buffers; no-drop queue = 30% buffers
Nonpriority queue= 90% buffers; priority queue = 10% buffers
Configuring Queuing and Scheduling on F-Series I/O Modules
Ingress Class Map Names
2q4t-8e-in-q1 and 2q4t-8e-in-q-default
4q4t-7e-in-q1, 4q4t-7e-in-q-default, 4q4t-7e-in-q3,
and 4q4t-7e-in-q4
4q4t-6e-in-q1, 4q4t-6e-in-q-default, 4q4t-6e-in-q3,
and 4q4t-6e-in-q4