Users Guide

is received, a syslog message is generated and the peer version is recorded in the peer status table. If the
frame cannot be processed, it is discarded and the discard counter is incremented.
NOTE: Because DCBx TLV processing is best effort, it is possible that CIN frames may be processed when
DCBx is configured to operate in CEE mode and vice versa. In this case, the unrecognized TLVs cause the
unrecognized TLV counter to increment, but the frame is processed and is not discarded.
Legacy DCBx (CIN and CEE) supports the DCBx control state machine that is defined to maintain the
sequence number and acknowledge the number sent in the DCBx control TLVs.
DCBx Example
The following figure shows how to use DCBx.
The external 40GbE 40GbE ports on the base module (ports 33 and 37) of two switches are used for uplinks
configured as DCBx auto-upstream ports. The device is connected to third-party, top-of-rack (ToR) switches
through 40GbE uplinks. The ToR switches are part of a Fibre Channel storage network.
The internal ports (ports 1-32) connected to the 10GbE backplane are configured as auto-downstream ports.
Figure 34. DCBx Sample Topology
DCBx Prerequisites and Restrictions
The following prerequisites and restrictions apply when you configure DCBx operation on a port:
• For DCBx, on a port interface, enable LLDP in both Send (TX) and Receive (RX) mode (the protocol
lldp mode command; refer to the example in CONFIGURATION versus INTERFACE Configurations in
the Link Layer Discovery Protocol (LLDP) chapter). If multiple DCBx peer ports are detected on a local
DCBx interface, LLDP is shut down.
Data Center Bridging (DCB) 329