40 Brocade ICX 6650 Administration Guide
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Basic port parameter configuration
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•Negotiate-full-auto – The port first tries to perform a handshake with the other port to
exchange capability information. If the other port does not respond to the handshake attempt,
the port uses the manually configured configuration information (or the defaults if an
administrator has not set the information). This is the default.
•Auto-Gbps – The port tries to perform a handshake with the other port to exchange capability
information.
•Negotiation-off – The port does not try to perform a handshake. Instead, the port uses
configuration information manually configured by an administrator.
To change the mode for individual ports, enter commands such as the following.
Brocade(config)# interface ethernet 1/1/1 to 1/1/2
Brocade(config-mif-1/1/1-1/1/2)# gig-default auto-gig
This command overrides the global setting and sets the negotiation mode to auto-Gbps for ethernet
ports 1/1/1– 1/1/2.
Syntax: gig-default neg-full-auto | auto-gig | neg-off
NOTE
When Gbps negotiation mode is turned off (CLI command gig-default neg-off), the Brocade device
may inadvertently take down both ends of a link. This is a hardware limitation for which there is
currently no workaround.
Port priority (QoS) modification
You can give preference to the inbound traffic on specific ports by changing the Quality of Service
(QoS) level on those ports. For information and procedures, refer to the Brocade ICX 6650 Switch
Platform and Layer 2 Configuration Guide.
Port flap dampening configuration
Port Flap Dampening increases the resilience and availability of the network by limiting the number
of port state transitions on an interface.
If the port link state toggles from up to down for a specified number of times within a specified
period, the interface is physically disabled for the specified wait period. Once the wait period
expires, the port link state is re-enabled. However, if the wait period is set to zero (0) seconds, the
port link state will remain disabled until it is manually re-enabled.

Port flap dampening configuration notes

•When a flap dampening port becomes a member of a trunk group, that port, as well as all
other memb er ports of that tr unk group , will inh erit the p rimary port con figurat ion. This means
that the member ports will inherit the primary port flap dampening configuration, regardless of
any previous configuration.
•The Brocade device counts the number of times a port link state toggles from "up to down",
and not from "down to up".
•The sampling time or window (the time during which the specified toggle threshold can occur
before the wait period is activated) is triggered when the first "up to down" transition occurs.
•"Up to down" transitions include UDLD-based toggles, as well as the physical link state.