Service Manual

NOTE: To save the pfc buering conguration changes, save the conguration and reboot the system.
NOTE: Dell Networking OS Behavior: DCB is not supported if you enable link-level ow control on one or more interfaces.
For more information, refer to Ethernet Pause Frames.
QoS dot1p Trac Classication and Queue Assignment
The following section describes QoS dot1P trac classication and assignments.
DCB supports PFC, ETS, and DCBx to handle converged Ethernet trac that is assigned to an egress queue according to the
following QoS methods:
Honor dot1p You can honor dot1p priorities in ingress trac at the port or global switch level (refer to Default dot1p to
Queue Mapping) using the service-class dynamic dot1p command in INTERFACE conguration
mode.
Layer 2 class maps You can use dot1p priorities to classify trac in a class map and apply a service policy to an ingress port to
map trac to egress queues.
NOTE: Dell Networking does not recommend mapping all ingress trac to a single queue when using PFC and ETS.
However, Dell Networking does recommend using Ingress trac classication using the service-class dynamic
dot1p command (honor dot1p) on all DCB-enabled interfaces. If you use L2 class maps to map dot1p priority trac to
egress queues, take into account the default dot1p-queue assignments in the following table and the maximum number of
two lossless queues supported on a port (refer to
Conguring Lossless Queues).
Although Dell Networking OS allows you to change the default dot1p priority-queue assignments (refer to Setting dot1p
Priorities for Incoming Trac), DCB policies applied to an interface may become invalid if you recongure dot1p-queue
mapping. If the congured DCB policy remains valid, the change in the dot1p-queue assignment is allowed.
dot1p Value in
the Incoming
Frame
Egress Queue Assignment
0 2
1 0
2 1
3 3
4 4
5 5
6 6
7 7
SNMP Support for PFC and Buer Statistics Tracking
Buer Statistics Tracking (BST) feature provides a mechanism to aid in Resource Monitoring and Tuning of Buer Allocation. The
support for Max Use Count mode in Buer Statistics is introduced in Dell Networking OS 9.3(0.). Max Use Count mode provides the
maximum value of the counters accumulated over a period of time.
Priority Flow Control (PFC) provides a link level ow control mechanism, which is controlled independently for each frame priority.
The goal of this mechanism is to ensure zero loss under congestion in DCB networks.
The SNMP support for monitoring PFC and BST counters and statistics is introduced in Dell Networking OS 9.3(0.1). The
enhancement is made on F10-FPSTATS MIB with additional tables to display the PFC and BST counters and statistics.
The following new tables are added in F10-FPSTATS MIB in Dell Networking OS 9.3(0.1):
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Data Center Bridging (DCB)