User's Manual

EnRoute500 User’s Guide

TR0149 Rev. C5

may reserve the entire range of addresses, but the EnRoute500 will use at least the top

address in the range for DHCP.

> use wlan1

wlan1> set dhcp.reserve=5

The ‘dhcp.reserve’ setting for all access points and the wired interface can be set via the web

interface using the “DHCP” sub-tab under the “DHCP” tab on the “System Parameters” page

(see Figure 36).

If the ‘dhcp.reserve’ value is non-zero, the DHCP range start address will be affected as shown

below

Start address = <sys.id.lanprefix>.

<sys.id.mesh>.

<sys.id.node>.

<wlan1.ip.start.actual> + 1 - <wlan1.dhcp.reserve>

10.2 Using a Centralized DHCP Server

DHCP relay enables assignment of IP addresses to wireless clients from of a common remote

DHCP server. The remote DHCP server may reside either on a host connected to the mesh

gateway’s wired segment, or on a server that is beyond one or more routers. When using a

common DHCP server, wireless clients are assigned IP addresses from a single address pool,

and are allowed to keep their address while roaming seamlessly from AP to AP. Even though

they will not move seamlessly from one node to another, wired clients can also have their

addresses assigned by a centralized server.

Seamless roaming denotes roaming from AP to AP with the same ESSID, while

maintaining Layer 4 session persistence. Certain wireless utility / card combos will,

instead of resetting the network adapter, re-request their currently assigned IP

address from the DHCP server when connecting to a new AP with the same ESSID

as the last one it was connected to. This behavior will leave existing Layer 4

(TCP/UDP) sessions intact.

There are three classes of entities that must be configured when using this DHCP mode:

1. The individual EnRoute500s, including the repeaters and the gateway node

2. The central DHCP server

3. Any intermediate router(s) in the path between the DHCP server and the mesh cluster

gateway node

When using a centralized DHCP server, an address space, from which client addresses are

assigned, must be defined. The client interfaces on the EnRoute500s (there can be up to 5 per