Force 1G connection speed on physical interfaces

In some scenarios, it is desirable that connections on a specific interface be restricted to a lower speed than the maximum supported speed. Such scenarios occur when the device that is connected to the interface is unable to connect at the highest speed possible for that interface.

This speed setting is only supported on the 1G/10G copper ports (ports 1-48) of the SLX 9150-48XT and Extreme 8520-48XT devices to enable the user to force 1000Mbps (1G) speed setting on these interfaces in both full-duplex and half-duplex mode. The master/slave setting allows the interface to act as either a clock master or a slave in the forced speed setting.

The following speed configurations are available:

1000-auto-full-duplex
1000-master-full-duplex
1000-master-half-duplex
1000-slave-full-duplex
1000-slave-half-duplex

The 1000-auto-full-duplex command enables the configuration of the ports to be set at 1G speed and in full duplex mode.

To reset the above setting to the default setting of 1G/10G AN mode, use either the speed auto or the no speed command.

When using the master/slave configuration, ensure that the peer port is configured with the complimentary configuration for the port to come up. For example:

If the local port is configured as 1000-master-full-duplex, then the peer port must be configured as 1000-slave-full-duplex.
If the local port is configured as 1000-slave-half-duplex, then the peer port must be configured as 1000-master-half-duplex.
If the local port is configured as 1000-auto-full-duplex, then the peer port must be configured for auto-negotiation for the link to be established.

The show interface ethernet command is also enhanced to show the configured speed for the interface.

SLX(conf-if-eth-0/1-2)# do show interface ethernet 0/1
Ethernet 0/1 is up, line protocol is up (connected)
Hardware is Ethernet, address is f064.26f2.d80c
Current address is f064.26f2.d80c
Fixed Copper RJ45 Media Present
Interface index (ifindex) is 201334784 (0xc002000)
MTU 9216 bytes
Maximum Speed : 10G
LineSpeed Actual : 1000 Mbit
LineSpeed Configured : 1G forced master, Duplex: Half 
Priority Tag disable
Forward LACP PDU: Disable
Route Only: Disabled

Example

The following example displays the forced 1G configuration on the Extreme 8520-48XT device

8520-48XT# show interface ethernet 0/36
Ethernet 0/36 is up, line protocol is up (connected)
Hardware is Ethernet, address is f064.26f4.4c2f
    Current address is f064.26f4.4c2f
Fixed Copper RJ45 Media Present
Interface index (ifindex) is 201621504 (0xc048000)
MTU 9216 bytes
Maximum Speed        : 10G
LineSpeed Actual     : 1000 Mbit
LineSpeed Configured : 1G auto full, Duplex: Full
Priority Tag disable
Forward LACP PDU: Disable
Route Only: Disabled

Example

The following example how to configure the Force 1G speed configuration on an Extreme 8520-48XT device.

8520-48XT(config)# interface Ethernet 0/36
8520-48XT(conf-if-eth-0/36)# speed ?
Possible completions:
  100                       100Mbps
  1000                      1Gbps
  1000-auto                 1Gbps AN (802.3 Clause 37 Auto-Negotiation)
  1000-auto-full-duplex     1Gbps Auto Negotiation for copper cable
  1000-master-full-duplex   1Gbps - Set as Master with Full Duplex
  1000-master-half-duplex   1Gbps - Set as Master with Half Duplex
  1000-slave-full-duplex    1Gbps - Set as Slave with Full Duplex
  1000-slave-half-duplex    1Gbps - Set as Slave with Half Duplex
  10000                     10Gbps
  25000                     25Gbps
  40000                     40Gbps
  100000                    100Gbps
  auto                      Auto Detection (default)

8520-48XT(conf-if-eth-0/36)# speed 1000-auto-full-duplex
8520-48XT(conf-if-eth-0/36)# no shutdown
8520-48XT(conf-if-eth-0/36)# end
8520-48XT# show running-config interface Ethernet 0/36
interface Ethernet 0/36
speed 1000-auto-full-duplex
no shutdown
!
8520-48XT#