EXOS Link-Local IP

Link-Local addressing (subnet 169.254.x.x) allows a host device to automatically and predictably derive a non-routable IP address for IP communication over Ethernet links.
By configuring the Ethernet management port “just out of the box” with an IP address, a user can connect a laptop directly to the management Ethernet port. If the laptop is not configured with a fixed IP address, it tries to get an IP address from a DHCP server. If it cannot, it assigns its own Link-Local address putting the switch and the laptop on the same subnet. The laptop can then use Telnet or a web browser to access the switch removing the need for the serial cable.
The IPv4 address format is used to make it simple for a user to determine the switch’s IP address. The formula is to use the lower 2 bytes of the MAC address as the last two numbers in the Link-Local IPv4 address.

• MAC address: 00:04:96:97:E9:EE
• Link-Local IP address: 169.254.233.238 or 0xa9fee9ee

Web browsers accept a hexadecimal value as an IPv4 address. (Microsoft IE displays the URL with the number dot notation 169.254.233.239.)

The web URL is http://0xa9fee9ee or just 0xa9fee9ee
The user documentation directs the customer to access the web browser by typing 0xa9fe followed by the last two number/letter groups in the MAC address found on the switch label. No hexadecimal translation is required.
With this information, you can connect the Ethernet port directly from a laptop to this switch using the temporary Link-Local address. You can communicate via web or Telnet to perform the initial switch configuration, if needed, and no longer needs a serial cable to configure a switch.

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