Enterasys Networks CSX6000 - Manual (Page 316)

USER’S GUIDE
316 CyberSWITCH
DHCP C ONFIGURATION E LEMENTS
DHCP P ROXY C LIENT E NABLE /D ISABLE F LAG
A global flag that indicates whether the DHCP Proxy Client feature is enabled or not. The proxy
client is disabled by default.
M AXIMUM N UMBER OF IP A DDRESSES
Refers to the maximum number of IP addresses obtained from DHCP servers for this network
interface. This number of IP addresses can be leased from DHCP servers for this interface and
placed into the IP Address Pool. The range of this configuration value is 0 to “x” where “x” is the
size of the Address Pool. The default for this value is 0.
Note: If all available entries in the IP Address Pool are assigned to one IP network interfaces’s
maximum, there will not be any more available for other interfaces. Therefore, take care to
plan accordingly.
N UMBER OF IP A DDRESSES TO P RE - FETCH
The configured number of IP addresses to have available at all times for an IP network interface.
This means that the IP addresses have been placed in the IP Address Pool, but have not yet been
leased to any remote devices. These IP addresses are sitting in the IP Address Pool waiting to be
claimed by remote devices. The range of this configuration value is 0 to “x” where “x” is the
maximum IP addresses to obtain for the IP network interface. The default for this value is 0.
LAN P ORT ON WHICH TO REACH THE DHCP S ERVER
This configuration value contains the number of the LAN port to use in order to reach a DHCP
server. The range of this value is 1 to “x” where “x” is the number of configured LAN ports. The
default for this value is 1.
DHCP B ACKGROUND I NFORMATION
The DHCP Proxy Client feature enables the CyberSWITCH to dynamically obtain IP addresses
from a DHCP server for IP host devices that support PPP. This feature compliments the
DHCP
Relay Agent feature, which supports remote bridges. Both features together allow the
CyberSWITCH to access the DHCP server to allocate IP addresses to all types of remote IP devices,
rather than maintaining separate IP address pools for separate devices.
Remote IP devices that use PPP to connect to the CyberSWITCH use PPP IPCP IP Address
negotiation to dynamically obtain their IP addresses. In general, those devices are not capable of
using DHCP to obtain the dynamic IP addresses. However, with the DCHP Proxy Client feature,
the CyberSWITCH “pretends” to be a DHCP client. When a connection is established and a remote
IP host device requests an IP address, the CyberSWITCH (acting as a DHCP client) obtains an IP
address from the DHCP server. It then gives it to the remote device via IPCP.
The CyberSWITCH is capable of prefetching some number of IP addresses so that connections can
be established faster. You may configure two numbers for each WAN type network interface: the
number of the IP addresses to prefetch (“x”), and the maximum number of IP addresses to obtain
(“y”). The CyberSWITCH will prefetch “x” IP addresses for the network interface until it has
obtained “y” addresses. For example, if the number to prefetch is 3, and the maximum number is
5, then 3 IP addresses will be prefetched immediately. As one IP address is assigned to a remote
device, one IP address is obtained from a DHCP server until the total of 5 IP addresses have been
obtained.