9-14
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
Chapter 9 Configuring the Switch Interfaces
Configuring Switch Interfaces
service timestamps log uptime
no service password-encryption
!
hostname Switch
!
<output truncated>
!
interface FastEthernet0/3
switchport mode trunk
no ip address
duplex half
speed 10
!
<output truncated>

Configuring Media Types for Gigabit Interfaces

You can use the media-type inte rface con figura ti on co mm an d to c onfigure t he m ed ia- type fo r Giga bit
iinterfaces. The media-type interface configuration command allows you to enable or disable fiber-optic
or copper connect ions on a Long -Reach Eth ernet (L RE) switc h. It also allows you to manu ally set the
port to select an SFP connector or an RJ45 connector. Use the no form of this comm and to return to the
default setting of SFP-preferred. To configure media types, use the command:
media-type {auto-select | sfp | rj45}
See the Catalyst 2950 Desktop Switch Command Reference for fu rthe r det ails .

Configuring IEEE 802.3X Flow Control on Gigabit Ethernet Ports

Flow control is supported only on switch and module ports operating at 1000 Mbps. Flow control enables
connected Gigabit Ethernet ports to control traffic rates during congestion by allo wing congested nodes
to pause link operation at the other end. If one port experiences congestion and cannot receive any more
traffi c , it notifies the other por t to stop sending until th e co nditi on clea rs. When the loca l de v ic e detects
any congestion at its end, it can notify the link partner or the remote device of the congestion b y sending
a pause frame. Upon receipt of a pause frame, the remote device stops sending any data packets, which
prevents any loss of data pa ckets during the congestion period.
Note We strongly recommend that you do not configure IEEE 802.3X flowcontrol when quality of service
(QoS) is configured on the switch. Before configuring flowcontrol on an interface, mak e sure t o r e t ur n t o
the default QoS settings listed in the “Default QoS Configuration” section on page 26-9.
Flow control can be implemented in two forms, symmetric and asymmetric. The symmetric
implementation is suitable for point-to-point links, and asymmetric is suitable for hub-to-end node
connec tions, w here it is de sirable fo r the hub to pause the en d system, but not vic e-versa. You use the
flowcontrol interface configuration command to set the interface’s ability to receive and send pause
frames to on, off, or desired. The default state for Gigabit Ethernet ports is re ceive o ff and send desired.
The default state for Fast Ethe rnet port s is receive off and send off.