LLDP

LLDP can be used to dynamically enable domain defense on a port for a CNPV. Since Congestion Notification requires every node in the path to be capable of congestion notification support, the nearest bridge LLDP address is used in advertising the support. LLDP TLV type 127 is used by congestion notification and includes a:

• Per-priority CNPV indicator – An 8-bit field where each bit represents the priority for the port and if it‘s capable of congestion notification.
• Per-priority ready indicator – An 8-bit field where each bit represents the priority for the port and if it‘s ready for congestion notification (set to 1 if the port is enabled for CNPV).

If a congestion notification capable port receives a TLV type 127 signaling that its neighbor is capable on the same CNPV, the ready indicator is set and the port transitions from the edge to the interior ready domain defense mode for that CNPV.

For dynamic configuration of domain defense to take place you must:

• Assure that the global priority choice is set to auto (default setting when creating a CNPV in creation enable mode)
• Enable congestion notification LLDP on the device using the set dcb cn priority lldp command (defaults to enabled)
• Enable the sending of congestion notification TLVs on each congestion point port using the set lldp port tx-tlv congestion-notif command (defaults to disabled)