Cnd; Cnd Defense Mode; Priority Mapping; Protocols And Standards - HP FlexFabric 5700 series Configuration Manual

CND

A CND is a set of RPs and CPs enabled with QCN for a CNPV. CNDs are identified based on CNPVs.
Devices enabled with QCN for a CNPV are assigned to the corresponding CND. A CNPV-based CND
prevents traffic from outside the CND from entering the CND. If a frame from outside the CND includes
the CNPV, the 802.1p priority value of the frame is mapped to a configured alternate priority value.

CND defense mode

Each interface on a device in a CND has a defense mode, which is statically configured or negotiated
through LLDP.
The following defense modes are available:
• disabled—Disables congestion notification and performs priority mapping according to the priority
mapping table.
edge—Maps the priority of incoming frames with a CNPV to an alternate priority and removes CN
•
tags before sending out the frames.
interior—Does not alter the priority of incoming frames with a CNPV and removes CN tags before
•
sending out the frames.
interiorReady—Does not alter the priority of incoming frames with a CNPV and retains CN tags
•
when sending out the frames.

Priority mapping

Incoming frames with a CNPV are assigned to the corresponding output queue enabled with QCN.
Traffic with other priority values cannot enter that output queue. Priority-to-queue mappings are
determined by the QoS priority mapping table (see
Modifying the priority mapping table for traffic with specific CNPVs might cause the system to fail to
detect congestion.
When you map multiple 802.1p priorities to one queue, all packets with these 802.1p priorities will be
included when determining congestion conditions. Therefore, do not map 802.1p priorities not enabled
with QCN to a queue enabled with QCN.
Marking actions configured in QoS policies affect priority mapping. For information about marking
actions, see
The priority trust mode must be configured as the 802.1p priority. For information about configuring trust
modes, see
The default port priority cannot be the same as the CNPV. For information about port priority, see
"Configuring priority

Protocols and standards

IEEE 802.1Qau, Congestion notification
"Configuring priority marking."
"Configuring priority mapping."
mapping."
"Configuring priority
99
mapping").