Hameg HO720 страница 25 Скачать руководство пользователя

Страница: 25 / 29

Ethernet Configuration

5 Ethernet

Configuration

5.1 IP networks (IP – Internet protocol)

In order that two or several network elements (e.g. measu-
ring instruments, host/PC‘s, …) can communicate over a
network with one another, some fundamental connections
have to be considered, so that data communication is error
free and unimpaired.

For each element in a network an IP address has to be as-
signed, so that they can exchange data among themselves.
IP addresses are represented (with the IP version 4) as four
decimal numbers separated by points (e.g. 192.168.15.1).
Each decimal number is represented by a binary number
of 8 bits. IP addresses are divided into public and private
address ranges. Public IP addresses will be able to route
by the Internet and an Internet service Provider (ISP) can
to be made available. Public IP addresses can be reached
directly over the Internet to directly exchange internet data.
Private IP addresses are not routed by the Internet and
are reserved for private networks. Network elements with
private IP addresses cannot be reached directly over the
Internet so no data can be directly exchanged over the In-
ternet. To allow network elements with a private IP address
to exchange data over the Internet, they require a router
for IP address conversion (English NAT; Network address
translation), before connection to the Internet. The attached
elements can then data exchange over this router, which
possesses a private IP address (LAN IP address) and also a
public IP address (WAN IP address), via the Internet.

If network elements exchange data only over a local net-
work (without connection with the Internet), appropriate

The host (PC) must have an Ethernet LAN interface inserted. For

the configuration of this interface you will find further informa

tion in its PC manual or in the manual of your network interface.

use private IP addresses. Select in addition e.g. a private IP
address for the instrument and a private IP address for the
host (PC), with which you would like to control the instru-
ment. If you might connect your private network with the
Internet later via a router, the private IP addresses used in
your local network can be maintained. Since within each

IP address range the first IP address is used as network

IP address and the last IP address is used as Broadcast IP
address, in each case two IP addresses have to be taken
off from the “number of possible host addresses“ (see
table 1: Private IP address ranges).

Apart from the organization of IP addresses into public and
private address ranges, IP addresses are also divided into
classes (Class: A, B, C, D, E). Within the classes A, B, and
C are also include the private IP of address ranges descri-
bed before. The categorisation from IP addresses is for
the assignment of public IP address ranges of importance
and essentially depends on the size of a local network
(maximum number of hosts in the network), which is to
be connected with the Internet (see table 2: Classes of IP

addresses). IP addresses can fix (statically) or variable (dy

namically) to be assigned. If IP addresses in a network are

assigned fix, an IP address must be preset manually with

each network element. If IP addresses in a network are
assigned to the attached network elements automati

Fig. 5.1: Ethernet settings example

Class

Adress range

Net quota

Host quota Max. number of networks Max. number of hosts

0.0.0.1 - 127.255.255.255

8 Bit

24 Bit