Dell PowerConnect 8100 User's Configuration Guide - Page 819

DCBX information is carried over LLDP, which is a link-local protocol. When configuring links in a port channel to use DCBX, the DCBX settings should be the same for all links in the port channel. Interoperability with IEEE DCBx To be interoperable with legacy industry implementations of the DCBx protocol, The PowerConnect 8024/8024F/81xx switches use a hybrid model to support both the IEEE version of DCBx (IEEE 802.1Qaz) and legacy DCBx versions. The PowerConnect 8024/8024F/81xx switch automatically detects whether a peer is operating with either of the two CEE DCBx versions or the IEEE standard DCBx version (the default mode). You can also configure DCBx to manually select one of the legacy versions or IEEE standard mode. In autodetect mode, the switch starts operating in IEEE DCBx mode on a port, and if it detects a legacy DCBx device based on the OUI of the organization TLV, then the switch changes its DCBx mode on that port to support the version detected. There is no timeout mechanism to move back to IEEE mode. If the DCBx peer times out, multiple peers are detected, the link is reset (link down/up) or if commanded by the operator, DCBx resets its operational mode to IEEE. The interaction between the DCBx component and other components remains the same irrespective of the operational mode it is executing. For instance, the DCBx component interacts with PFC to get needed information to pack the TLVs to be sent out on the interface. Based on the operational control mode of the port, DCBx packs it in the proper frame format. DCBx and Port Roles The behavior of each port is dependent on its operational mode and that of other ports in the stack. The port mode is a DCBx configuration item that is passed to the DCBx clients to control the processing of their configuration information. There are four port roles: 1 Manual 2 Auto-Upstream 3 Auto-Downstream 4 Configuration Source Configuring Data Center Bridging Features 819