Enterasys Networks X-PeditionTM manual Provisioning Differentiated Network Values by Client Class

DHCP Services

control data are carried in tagged data items which are stored in the options field of the DHCP message. The data items themselves, also called options, are enabled on the XSR by the options command specifying IP address, hex or ASCII string values. Supported options are defined in the “Dynamic Host Configuration Protocol Commands” chapter of the XSR CLI Reference Guide.

RFC-1122 specifies default values for most IP/TCP configuration parameters.

Provisioning Differentiated Network Values by Client Class

One DHCP option - supported on the XSR by the client-classcommand - groups clients into classes with differentiated configuration. A DHCP Server selects appropriate parameters for the clients belonging to this class. For example, a Client Class can configure all enterprise users in Accounting with a different lease time than users in Marketing. RFC-3004 defines the User Class (Client Class) option for DHCP.

BOOTP Legacy Support

The XSR provides backward compatibility with BOOTP clients. When configured with a manual binding, it supplies a specified IP address to the client as well as a TFTP server IP address and file name to download (with the next-servercommand).

Refer to “BOOTP Client Support Example” on page 15-12for more information.

Nested Scopes: IP Pool Subsets

As mentioned earlier, one of the main functions of the DHCP Server is to allocate IP addresses to clients. In that process, the DHCP Server works with three scopes or resource sets responsible for aggregated DHCP attributes - Pools or subnets, Client Classes, and Hosts. Scopes can be assigned other attributes as well as IP addresses, and can nest these attributes hierarchically much like files are organized in a directory tree. How these scopes interrelate can be loosely illustrated as shown in Figure 15-1.

Figure 15-1 DHCP Nested Scopes

Pool (subnet)

192.168.57.0

Values are inherited from outer scopes

Client Class

Elite

Values are inherited from outer scopes

A nested scope may override an outer scope attribute

Host

lcurtis-xp

Attributes persist at the Host level

The Pool scope in Figure 15-1defines and manipulates IP addresses and parameters. The Client Class scope manages sets of clients requesting DHCP Server services. The Host scope controls DHCP user parameters.

15-4 Configuring DHCP XSR User’s Guide