Dhcp; Overview - Sena NEMO10 User Manual

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> set ip static 192.168.1.10 255.255.255.0 192.168.1.1

Figure 3-1. Setting IP configuration parameters for Static IP mode

3.2 DHCP

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

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

network. DHCP lets a network administrator 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 3.1, 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 to assign an IP address are configured on DHCP server side, and each

DHCP client computer receives this information when the IP address is provided at its boot-up.

To obtain an IP address, theNEMO10 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 NEMO10 immediately

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

NEMO10 will request the DHCP server for renewal of its lease time. If the DHCP server approves

extending the lease, the NEMO10 can continue to work with the current IP address. Otherwise, the

NEMO10 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 NEMO10, receives a different IP address

each time it boots up. To prevent the case that users do not know the IP address of the NEMO10 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 NEMO10 found

on the label sticker at the bottom of the NEMO10:

MAC=00:01:95:04:0c:a1

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