<div>
Hi,<br />
<br />
Please read the below:<br />
<br />
<a href="http://www.ciscohomelab.com/troubleshooting/when-to-use-a-crossover-with-auto-mdix/" rel="ugc">http://www.ciscohomelab.com/troubleshooting/when-to-use-a-crossover-with-auto-mdix/</a><br />
<a href="http://www.cisco.com/en/US/tech/tk389/tk214/technologies_tech_note09186a0080094781.shtml" rel="ugc">http://www.cisco.com/en/US/tech/tk389/tk214/technologies_tech_note09186a0080094781.shtml</a>
</div>


Hi,

Please read the below:

http://www.ciscohomelab.com/troubleshooting/when-to-use-a-crossover-with-auto-mdix/ [http://www.ciscohomelab.com/troubleshooting/when-to-use-a-crossover-with-auto-mdix/]
http://www.cisco.com/en/US/tech/tk389/tk214/technologies_tech_note09186a0080094781.shtml [http://www.cisco.com/en/US/tech/tk389/tk214/technologies_tech_note09186a0080094781.shtml]

<div>
By default auto MDIX is off. Also Auto MDIX is not supported on 1000 BASE-SX or -LX SFP interfaces.<br />
<br />
To turn Auto MDIX on on an interface use this (yes you need to set speed and duplex to auto also):<br />
<br />
Switch# configure terminal<br />
Switch(config)# interface gigabitethernet1/0/1<br />
Switch(config-if)# speed auto<br />
Switch(config-if)# duplex auto<br />
Switch(config-if)# mdix auto<br />
Switch(config-if)# end<br />
<br />
To turn it off:<br />
<br />
Switch# configure terminal<br />
Switch(config)# interface gigabitethernet1/0/1<br />
Switch(config-if)# speed &lt;100/1000/auto&gt;<br />
Switch(config-if)# duplex &lt;half/full/auto&gt;<br />
Switch(config-if)# no mdix auto<br />
Switch(config-if)# end<br />
<br />
Regards,<br />
Raymond Zwarts
</div>


By default auto MDIX is off. Also Auto MDIX is not supported on 1000 BASE-SX or -LX SFP interfaces.

To turn Auto MDIX on on an interface use this (yes you need to set speed and duplex to auto also):

Switch# configure terminal
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# speed auto
Switch(config-if)# duplex auto
Switch(config-if)# mdix auto
Switch(config-if)# end

To turn it off:

Switch# configure terminal
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# speed <100/1000/auto>
Switch(config-if)# duplex <half/full/auto>
Switch(config-if)# no mdix auto
Switch(config-if)# end

Regards,
Raymond Zwarts

<div>
yes. sorry about that.<br />
<br />
mdix is not supported on 3550
</div>


yes. sorry about that.

mdix is not supported on 3550

<div>
<div class="content wysiwyg-content">
How do I turn off or set auto MDIX on a 3550 series cisco switch?
</div>
</div>


How do I turn off or set auto MDIX on a 3550 series cisco switch?

MDIX on a 3550 Switch

A switch is a device that filters and forwards packets of data between LAN segments. Switches operate at the data link layer or the network layer of the Open Systems Interconnection (OSI) Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. A hub is a connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports; when a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

Switches / Hubs

Networking hardware includes the physical devices facilitating the use of a computer network. Typically, networking hardware includes gateways, routers, network bridges, modems, wireless access points, networking cables, line drivers, switches, hubs, and repeaters. But it also includes hybrid network devices such as multilayer switches, protocol converters, bridge routers, proxy servers, firewalls, network address translators, multiplexers, network interface controllers, wireless network interface controllers, ISDN terminal adapters and other related hardware.