3-3
Cisco ME 3400 EthernetAccess Switch SoftwareConfiguration Guide
78-17058-01
Chapter3 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 3-9
Default Switch Information
Table 3 -1 shows the default switch information.
Understanding DHCP-Based Autoconfiguration
DHCP provides configuration information to Internet hosts and internetworkin g devices. This prot ocol
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 pa ram eters t o
dynamically configured devices. The switch can act as a DHCP client, but it cannot be 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 various lease options associated with IP addresses.
If you are using DHCP to relay the configuration file location on th e net work, you mig ht a lso ne ed 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 s witch. If the
DHCP server is running on a different LAN, you should configure a DHCP r ela y device be tween y our
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 switc h. I f th e c onfiguration 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.
Table3-1 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.