
17. PCMCIA ETHERNET FUNCTION
B–63833EN–1/02
982
IP addresses are internationally managed systematically. This means that
before an IP address can be used, the IP address must be obtained formally
from the international organization.
If the network used by a user is a local network closed within the user’s
environment (not connected to an outside network), unique IP addresses
may be set freely under the control and responsibility of the user. For a
local network, the following network addresses can be used without
formal registration: 1 address (10) for class A, 16 addresses (172.16 to
172.31) for class B, and 256 addresses (192.168.0 to 192.168.255) for
class C. So, it is recommended that IP addresses with these network
addresses be used for a local network.
Mask address for indicating the network address section of an IP address.
For a network of class A, specify 255.0.0.0.
For a network of class B, specify 255.255.0.0.
For a network of class C, specify 255.255.255.0.
A MAC address is assigned to the Ethernet control board of each
communication device, and is used to identify each communication
device on the MAC layer (lower part of the data link layer). A unique
address obtained from an international organization is used so that no
address duplication occurs among Ethernet control board suppliers.
The port number is a 16–bit integer used to associate the transport layer
(TCP or UDP) of TCP/IP and a process of the application layer. Port
numbers from 0 to about 8000 are called well–known port numbers and
assigned to standard applications (such as Telnet and FTP). The
assignment of port numbers is described in Assigned Numbers
[RFC1340].
When using the FOCAS1/Ethernet function and DNC1/Ethernet
function, assign port numbers other than the well–known port numbers.
Transmitting a message to all nodes in the same segment
Device or application that requests a service
Device or application that provides a service
Subnet mask (mask
address)
MAC address (Ethernet
address)
Port number
Broadcast
Client
Server