The dhcp client, The dhcp server, The dhcp client the dhcp server – ELSA Cable User Manual

Page 49

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Operating modes and functions

ELSA MicroLink Cable

41

The cable modem really belongs to two LANs:

On one side it is a part of the LAN of the cable network operator and forms a LAN
together with the headend and all connected cable modems. The cable network
operator assigns the IP addresses to the participants via DHCP.

On the other side the cable modem forms a separate LAN with one or more
connected computers. DHCP can also be used to manage addresses within your
own LAN.

The cable modem thus functions as a DHCP client and as a DHCP server.

Whenever IP addresses of the cable modem are mentioned in the following paragraphs,
this is a reference to the LAN IP address of the ELSA MicroLink Cable, unless something
else is explicitly stated.

The DHCP client

The cable IP address for the exchange of data in the cable network is assigned via DHCP
by the network operator during registration at the headend, i.e. the network participant
has no influence on this process. Apart from the IP address used by the cable modem
when active on the cable network, additional information is transmitted such as the cable
network operator's gateway into the Internet or the time server.

Since this assignment via DHCP from the cable network to the cable modem is
mandatory, it is not necessary to configure the DHCP client. Current assignments can be
read at any time in the

Status/DHCP client status

menu.

The DHCP server

As a DHCP server, the

ELSA MicroLink Cable can manage the IP addresses in its TCP/IP

network. In doing so, it passes the following parameters to the workstation computers:

IP address

Network mask

Broadcast address

DNS

NBNS

Default gateway

Period of validity for the parameters assigned

The DHCP server takes the IP addresses either from a freely defined address pool or
determines the addresses automatically from its own LAN IP address.

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