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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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Chapter 6 Configuring Interfaces
Configuring Optional Interface Features
The ports on both ends of a link must have the same setting. The link will not come up if the ports at
each end of the link are set inconsistently (link negotiation enabled on one port and disabled on the other
port).
Table 6-1 shows the four possible link negotiation configurations and the resulting link status for each
configuration.
To configure link negotiation on a port, perform this task:
This example shows how to enable link negotiation on Gigabit Ethernet port 5/4:
Router(config)# interface gigabitethernet 5/4
Router(config-if)# no speed nonegotiate
Displaying the Speed and Duplex Mode Configuration
To display the speed and duplex mode configuration for a port, perform this task:
This example shows how to display the speed and duplex mode of Fast Ethernet port 5/4:
Router# show interfaces fastethernet 5/4
FastEthernet5/4 is up, line protocol is up
Hardware is Cat6K 100Mb Ethernet, address is 0050.f0ac.3058 (bia 0050.f0ac.3058)
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:33, output never, output hang never
Table 6-1 Link Negotiation Configuration and Possible Link Status
Link Negotiation State Link Status
Local Port Remote Port Local Port Remote Port
Off Off Up Up
On On Up Up
OffOnUpDown
On Off Down Up
Command Purpose
Step 1 Router(config)# interface gigabitethernet
slot/port
Selects the port to be configured.
Step 2 Router(config-if)# speed nonegotiate Disables link negotiation.
Router(config-if)# no speed nonegotiate Reverts to the default configuration (link negotiation
enabled).
Command Purpose
Router# show interfaces type1 slot/port
1. type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet
Displays the speed and duplex mode configuration.