Dhcp; Overview; Dhcp Configuration - Sena HelloDevice Lite Series User Manual

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4.2 DHCP

Dynamic Host Configuration Protocol (DHCP) is a communications protocol that allows network

administrators to manage and automate the assignment of IP addresses centrally in an organization's

network. DHCP allows a network administrator to supervise and distribute IP addresses from a central

point and automatically send a new IP address when a computer is plugged into a different place in

the network.

As described in the section 4.1, the IP address must be entered manually at each computer in Static

IP mode and, if computers move to another location in another part of the network, a new IP address

must be entered. Meanwhile, all the parameters including the IP address, subnet mask, gateway, DNS

servers will be automatically configured when the IP address is assigned in DHCP mode. DHCP uses

the concept of a "lease" or amount of time for which a given IP address will be valid for a computer. All

the parameters required are assigned by the DHCP server, and each DHCP client computer receives

the proper network information at boot-up.

To obtain an IP address, the LS100W sends a corresponding DHCP request as a broadcast over the

network after each reset. The reply generated by the DHCP server contains the IP address as well as

the subnet mask, gateway address, DNS servers and the lease time. The LS100W immediately places

this information in its non-volatile memory. If the operating time reaches the lease time, the LS100W

will request the DHCP server for renewal of its lease time. If the DHCP server approves extending the

lease, the LS100W can continue to work with the current IP address. Otherwise, the LS100W will start

the procedure to request a new IP address to the DHCP server.

A DHCP sever assigns IP addresses dynamically from an IP address pool, which is managed by the

network administrator. This means DHCP client, i.e. the LS100W, receives a different IP address each

time it boots up. To prevent the case that users do not know the IP address of the LS100W in such

environments, its IP address should be reserved on the DHCP server side. In order to reserve the IP

address in the DHCP network, the administrator needs the MAC address of the LS100W found on the

label sticker at the bottom of the LS100W:

To set the LS100W to work in DHCP mode, just set IP mode to DHCP as in Figure 4-2.

> set ip dhcp

MAC=00:0B:6B:19:16:9E

Figure 4-2. Setting DHCP mode

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