IBM RackSwitch G8000, Инструкция по применению

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© Copyright IBM Corp. 2011 Chapter 1. Switch Administration
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BOOTP/DHCP Client IP Address Services
For remote switch administration, the client terminal device must have a valid IP
address on the same network as a switch interface. The IP address on the client
device may be configured manually, or obtained automatically using IPv6 stateless
address configuration, or an IPv4 address may obtained automatically via BOOTP
or DHCP relay as discussed in the next section.
The G8000 can function as a relay agent for Bootstrap Protocol (BOOTP) or DHCP.
This allows clients to be assigned an IPv4 address for a finite lease period,
reassigning freed addresses later to other clients.
Acting as a relay agent, the switch can forward a client’s IPv4 address request to up
to five BOOTP/DHCP servers. In addition to the five global BOOTP/DHCP servers,
up to five domain-specific BOOTP/DHCP servers can be configured for each of up
to 10 VLANs.
When a switch receives a BOOTP/DHCP request from a client seeking an IPv4
address, the switch acts as a proxy for the client. The request is forwarded as a
UDP Unicast MAC layer message to the BOOTP/DHCP servers configured for the
client’s VLAN, or to the global BOOTP/DHCP servers if no domain-specific
BOOTP/DHCP servers are configured for the client’s VLAN. The servers respond to
the switch with a Unicast reply that contains the IPv4 default gateway and the IPv4
address for the client. The switch then forwards this reply back to the client.
DHCP is described in RFC 2131, and the DHCP relay agent supported on the
G8000 is described in RFC 1542. DHCP uses UDP as its transport protocol. The
client sends messages to the server on port 67 and the server sends messages to
the client on port 68.
BOOTP and DHCP relay are collectively configured using the BOOTP commands
and menus on the G8000.
Global BOOTP Relay Agent Configuration
To enable the G8000 to be a BOOTP (or DHCP) forwarder, enable the BOOTP relay
feature, configure up to four global BOOTP server IPv4 addresses on the switch,
and enable BOOTP relay on the interface(s) on which the client requests are
expected.
Generally, it is best to configure BOOTP for the switch IP interface that is closest to
the client, so that the BOOTP server knows from which IPv4 subnet the newly
allocated IPv4 address will come.