Users Guide

• Accepts the DCB conguration from a peer if a DCBx port is in “willing” mode to accept a peer’s DCB settings and then internally
propagates the received DCB conguration to its peer ports.
DCBx Port Roles
The following DCBx port roles are auto-congured on an Aggregator to propagate DCB congurations learned from peer DCBx
devices internally to other switch ports:
Auto-upstream The port advertises its own conguration to DCBx peers and receives its conguration from DCBx peers
(ToR or FCF device). The port also propagates its conguration to other ports on the switch.
The rst auto-upstream that is capable of receiving a peer conguration is elected as the conguration
source. The elected conguration source then internally propagates the conguration to other auto-
upstream and auto-downstream ports. A port that receives an internally propagated conguration
overwrites its local conguration with the new parameter values.
When an auto-upstream port (besides the conguration source) receives and overwrites its conguration
with internally propagated information, one of the following actions is taken:
• If the peer conguration received is compatible with the internally propagated port conguration, the link
with the DCBx peer is enabled.
• If the received peer conguration is not compatible with the currently congured port conguration, the
link with the DCBx peer port is disabled and a syslog message for an incompatible conguration is
generated. The network administrator must then recongure the peer device so that it advertises a
compatible DCB conguration.
The conguration received from a DCBx peer or from an internally propagated conguration is not stored in
the switch’s running conguration.
On a DCBx port in an auto-upstream role, the PFC and application priority TLVs are enabled. ETS
recommend TLVs are disabled and ETS conguration TLVs are enabled.
Auto-downstream The port advertises its own conguration to DCBx peers but is not willing to receive remote peer
conguration. The port always accepts internally propagated congurations from a conguration source. An
auto-downstream port that receives an internally propagated conguration overwrites its local conguration
with the new parameter values.
When an auto-downstream port receives and overwrites its conguration with internally propagated
information, one of the following actions is taken:
• If the peer conguration received is compatible with the internally propagated port conguration, the link
with the DCBx peer is enabled.
• If the received peer conguration is not compatible with the currently congured port conguration, the
link with the DCBx peer port is disabled and a syslog message for an incompatible conguration is
generated. The network administrator must then recongure the peer device so that it advertises a
compatible DCB conguration.
The internally propagated conguration is not stored in the switch’s running conguration. On a DCBx port in
an auto-downstream role, all PFC, application priority, ETS recommend, and ETS conguration TLVs are
enabled.
Default DCBx port role: Uplink ports are auto-congured in an auto-upstream role. Server-facing ports are auto-congured in an
auto-downstream role.
NOTE: You can change the port roles only in the PMUX mode. Use the following command to change the port roles:
dcbx port-role {auto-downstream | auto-upstream | config-source | manual}
manual is the default port role.
Data Center Bridging (DCB)
45