Cisco Catalyst 2000 Configuration Handbook page 80

By default, link negotiation (flow control, duplex, fault information) is enabled on
Gigabit Ethernet ports. To disable negotiation, use the disable or no keyword.
(Optional; Catalyst 6500 only) Enable the port debounce timer:
6.
(interface) link debounce [time debounce_time]
By default, the line cards wait 300 milliseconds (10 milliseconds for fiber Gigabit
ports) before announcing to the main processor that a port has changed state. This
"debounces" the up/down state change so that quick changes do not trigger
Spanning Tree Protocol (STP), Port Aggregation Protocol (PAgP), Simple Network
Management Protocol (SNMP) traps, and so on. This debounce gives a port the
chance to settle down to a stable state. If you find that this period is too short, you
can enable an extended port debounce for specific ports. When enabled, the
debounce period becomes 3.1 seconds (100 milliseconds for fiber Gigabit ports).
Note When link debounce is enabled, port up/down detection is delayed. The normal
STP state progression, along with PAgP negotiation, can cause a long delay before a port
can become usable. Use this with caution.
(Optional) Optimize the port as a connection to a single host:
7.
(interface) switchport host
Several options are set for the port: STP PortFast is enabled, trunk mode is disabled,
EtherChannel is disabled, and no dot1q trunking is allowed. This optimizes the link
startup time when the port is attached to only one host.
(Optional) Use inline power where an IP Phone is connected:
8.
(interface) power inline {auto | never}
On ports or line cards that can support inline power to IP phones, power is supplied
if an IP Phone is detected on the port by default (auto). If power should never be
supplied to a connected device, choose the off or never keyword. See Chapter 14,
"Voice," for more configuration information.
(Optional) Allow large or jumbo frames:
9.
(interface) mtu bytes
By default, the maximum frame size or maximum transmission unit (MTU) that
can be switched is 1548. Sometimes you might need to switch larger packets to
improve performance from server to server. To allow switching of packets up to 9216
bytes, set an MTU size of bytes (1500 to 9216 bytes).
Tip Enabling jumbo frame support allows large frames to be switched. If they also need
to be routed, make sure that the MTU on the respective router interfaces is set to the same
size. Jumbo frame support is available on an MSFC2 or higher with the mtu interface com-
mand but is not available on the Multilayer Switch Feature Card (MSFC).
Chapter 4: Layer 2 Interface Configuration 59