235
To be interoperable with legacy industry implementations of DCBX protocol, QNOS software uses a hybrid
model to support both the IEEE version of DCBX (IEEE 802.1Qaz) and legacy DCBX versions.
QNOS software automatically detects if a peer is operating with either of the two CEE DCBX versions or the
IEEE standard DCBX version. This is the default mode. You can also configure DCBX to manually select one of
the legacy versions or IEEE standard mode. In auto-detect 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. Once the DCBX peer times out, multiple peers are detected, the link is reset (link
down/up) or as 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 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.
9.3.2.
DCBX and Port Roles
Each port's behavior is dependent on the operational mode of that port and of other ports in the switch. 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:
Manual
Auto-Upstream
Auto-Downstream
Configuration Source
Ports operating in the manual role do not have their configuration affected by peer devices or by internal
propagation of configuration. These ports have their operational mode, traffic classes, and bandwidth
information specified explicitly by the operator. These ports advertise their configuration to their peer if
DCBX is enabled on that port. Incompatible peer configurations are logged and counted with an error
counter.
The default operating mode for each port is manual. A port that is set to manual mode sets the willing bit
for DCBX client TLVs to false. Manually- configured ports never internally propagate or accept internal or
external configuration from other ports, in other words, a manual configuration discards any automatic
configuration. Manually-configured ports may notify the operator of incompatible configurations if client
configuration exchange over DCBX is enabled. Manually- configured ports are always operationally enabled
for DCBX clients, regardless of whether DCBX is enabled. Operationally enabled means that the port reports
that it is able to operate using the current configuration.
A port operating in the auto-upstream role advertises a configuration, but it is also willing to accept a
configuration from the link-partner and propagate it internally to the auto-downstream ports as well as
receive configuration propagated internally by other auto-upstream ports. Specifically, the willing parameter
is enabled on the port and the recommendation TLV is sent to the peer and processed if received locally.
The first auto- upstream port to successfully accept a compatible configuration becomes the configuration
source. The configuration source propagates its configuration to other auto-upstream and auto-
downstream ports. Only the configuration source may propagate configuration to other ports internally.
Summary of Contents for QuantaMesh QNOS5
Page 1: ...QuantaMesh Ethernet Switch Configuration Guide QNOS5 NOS Platform ...
Page 209: ...209 Table 7 8 IPv6 Neighbor Discovery Settings ...
Page 226: ...226 Table 8 2 L3 Multicast Defaults ...
Page 254: ...254 Appendix A Term and Acronyms Table 9 5 Terms and Acronyms ...
