Quanta Cloud Technology QuantaMesh QNOS5, Configuration Manual

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Expandable ports allow the administrator to configure a 40GbE port in either 4×10GbE mode or 1×40GbE
mode. When the 40GbE port is operating in 4×10GbE mode, the port operates as four 10GbE ports, each on
a separate lane. This mode requires the use of a suitable 4×10GbE to 1×40GbE pigtail cable.
Expandable port capability can be enabled on 40G ports using the CLI command [no] port-mode . A change
to the port mode is made effective immediately.
1.1.19. VLAN-aware MAC-based Switching
Packets arriving from an unknown source address are sent to the CPU and added to the Hardware Table.
Future packets addressed to or from this address are more efficiently forwarded.
1.1.20. Back Pressure Support
On half-duplex links, a receiver may prevent buffer overflows by jamming the link so that it is unavailable
for additional traffic. On full duplex links, a receiver may send a PAUSE frame indicating that the transmitter
should cease transmission of frames for a specified period.
When flow control is enabled, the switch will observe received PAUSE frames or jamming signals, and will
issue them when congested.
1.1.21. Auto Negotiation
Auto negotiation allows the switch to advertise modes of operation. The auto negotiation function provides
the means to exchange information between two switches that share a point-to-point link segment, and to
automatically configure both switches to take maximum advantage of their transmission capabilities.
The switch enhances auto negotiation by providing configuration of port advertisement. Port
advertisement allows the system administrator to configure the port speeds that are advertised.
1.1.22. Storm Control
When Layer 2 frames are forwarded, broadcast, unknown unicast, and multicast frames are flooded to all
ports on the relevant virtual local area network (VLAN). The flooding occupies bandwidth, and loads all
nodes connected on all ports. Storm control limits the amount of broadcast, unknown unicast, and
multicast frames accepted and forwarded by the switch.
Per-port and per-storm control type (broadcast, multicast, or unicast), the storm control feature can be
configured to automatically shut down a port when a storm condition is detected on the port; or to send a
trap to the system log. When configured to shut down, the port is put into a diag-disabled state. The user
must manually re-enable the interface for it to be operational. When configured to send a trap, the trap is
sent once in every 30 seconds. When neither action is configured, the switch rate-limits the traffic when
storm conditions occur.
1.1.23. Port Mirroring