Basic Operation Guide 2014/02

Table 8 Features available with and without IP addressing on the switch (continued)
Additional features available with an IP Address and subnet
mask
Features available without an IP Address
• TACACS+, RADIUS, SSH, SSL, and 802.1X
authentication
• Console-based status and counters information for
monitoring switch operation and diagnosing problems
through the CLI or menu interface
• Multinetting on VLANs
• VLANs and GVRP
• Telnet access to the CLI or the menu interface
• Serial downloads of software updates and configuration
files (Xmodem)
• IGMP
• TimeP and SNTP server configuration
• Link test
• TFTP download of configurations and software updates
• Port monitoring
• Access Control Lists (ACLs)
• Password authentication
• IP routing, Multicast Routing
• Quality of Service (QoS)
• VRRP router redundancy
• Authorized IP manager security
• PIM-DM and PIM-SM
• Radius
• Ping test
DHCP/Bootp operation
Overview. DHCP/Bootp is used to provide configuration data from a DHCP or Bootp server to the
switch. This data can be the IP address, subnet mask, default gateway, Timep Server address, and
TFTP server address. If a TFTP server address is provided, this allows the switch to TFTP a previously
saved configuration file from the TFTP server to the switch. With either DHCP or Bootp, the servers
must be configured prior to the switch being connected to the network.
NOTE: The switches covered in this guide are compatible with both DHCP and Bootp servers.
The DHCP/Bootp process. Whenever the IP Config parameter in the switch or in an individual
VLAN in the switch is configured to DHCP/Bootp (the default), or when the switch is rebooted
with this configuration:
1. DHCP/Bootp requests are automatically broadcast on the local network. (The switch sends
one type of request to which either a DHCP or Bootp server can respond.)
2. When a DHCP or Bootp server receives the request, it replies with a previously configured IP
address and subnet mask for the switch. The switch also receives an IP Gateway address if
the server has been configured to provide one. In the case of Bootp, the server must first be
configured with an entry that has the switch’s MAC address. (To determine the switch’s MAC
address, See Appendix D, “MAC Address Management”.) The switch properly handles replies
from either type of server. If multiple replies are returned, the switch tries to use the first reply.)
NOTE: If you manually configure default gateway, TTL, TimeP, and/or SNTP parameters on the
switch, it ignores any values received for the same parameters via DHCP or Bootp.
If the switch is initially configured for DHCP/Bootp operation (the default), or if it reboots with this
configuration, it begins sending request packets on the network. If the switch does not receive a
reply to its DHCP/Bootp requests, it continues to periodically send request packets, but with
decreasing frequency. Thus, if a DHCP or Bootp server is not available or accessible to the switch
when DHCP/Bootp is first configured, the switch may not immediately receive the desired
configuration. After verifying that the server has become accessible to the switch, reboot the switch
to re-start the process immediately.
DHCP operation. A significant difference between a DHCP configuration and a Bootp configuration
is that an IP address assignment from a DHCP server is automatic. Depending on how the DHCP
server is configured, the switch may receive an IP address that is temporarily leased. Periodically
the switch may be required to renew its lease of the IP configuration. Thus, the IP addressing
IP configuration 109