3-3
Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 3 Assigning the Switch IP Address and Default Gateway Assigning Switch Information
These sections contain this configuration information:
• Default Switch Information, page 3-3
• Understanding DHCP-Based Autoconfiguration, page 3-3
• Manually Assigning IP Information, page 3-14
Default Switch Information
Table 3-1 shows the default switch information.
Understanding DHCP-Based Autoconfiguration
DHCP provides configuration information to Internet hosts and internetworking devices. This protocol
consists of two components: one for delivering configuration parameters from a DHCP server to a device
and a mechanism for allocating network addresses to devices. DHCP is built on a client-server model,
in which designated DHCP servers allocate network addresses and deliver configuration parameters to
dynamically configured devices. The switch can act as both a DHCP client and a DHCP server.
During DHCP-based autoconfiguration, your switch (DHCP client) is automatically configured at
startup with IP address information and a configuration file.
With DHCP-based autoconfiguration, no DHCP client-side configuration is needed on your switch.
However, you need to configure the DHCP server for va rious lease optio ns associat ed with IP addresses .
If you are using DHCP to relay the configuration file location on the network, you might also need to
configure a Trivial File Transfer Protocol (TFTP) server and a Domain Name System (DNS) server.
The DHCP server for your switch can be on the same LAN or on a different LAN than the switch. If the
DHCP server is running on a different LAN, you should configure a DHCP relay device between your
switch and the DHCP server. A relay device forwards broadcast traffic between two directly connected
LANs. A router does not forward broadcast packets, but it forwards packets based on the destination IP
address in the received packet.
DHCP-based autoconfiguration replaces the BOOTP client functionality on your switch.

DHCP Client Request Process

When you boot your switch, the DHCP client is invoked and requests configuration information from a
DHCP server when the configuration file is not present on the switch. If the configuration file is present
and the configuration includes the ip address dhcp interface configuration command on specific routed
interfaces, the DHCP client is invoked and requests the IP address information for those interfaces.
Tab le 3-1 Default Switch Information
Feature Default Setting
IP address and subnet mask No IP address or subnet mask are defined.
Default gateway No default gateway is defined.
Enable secret password No password is defined.
Hostname The factory-assigned default hostname is Switch.
Telnet password No password is defined.