101-1226 Rabbit Semiconductor, 101-1226 Datasheet - Page 59

• Manufacturer Part Number: 101-1226
• Description: RCM3900 DEV KIT UNIVERSAL
• Manufacturer: Rabbit Semiconductor
• Series: RabbitCore 3900r
• Type: MPU Moduler

Specifications of 101-1226

• Contents: RabbitCore Module, Dev. Board, AC Adapter, Cable and Dynamic C® CD-Rom
• For Use With/related Products: RCM3900
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 316-1137

6.2 TCP/IP Primer on IP Addresses
Obtaining IP addresses to interact over an existing, operating, network can involve a number
of complications, and must usually be done with cooperation from your ISP and/or network
systems administrator. For this reason, it is suggested that the user begin instead by using a
direct connection between a PC and the RCM3900.
In order to set up this direct connection, you will have to use a PC without networking, or
disconnect a PC from the corporate network, or install a second Ethernet adapter and set
up a separate private network attached to the second Ethernet adapter. Disconnecting your
PC from the corporate network may be easy or nearly impossible, depending on how it is
set up. If your PC boots from the network or is dependent on the network for some or all
of its disks, then it probably should not be disconnected. If a second Ethernet adapter is
used, be aware that Windows TCP/IP will send messages to one adapter or the other,
depending on the IP address and the binding order in Microsoft products. Thus you should
have different ranges of IP addresses on your private network from those used on the cor-
porate network. If both networks service the same IP address, then Windows may send a
packet intended for your private network to the corporate network. A similar situation will
take place if you use a dial-up line to send a packet to the Internet. Windows may try to
send it via the local Ethernet network if it is also valid for that network.
The following IP addresses are set aside for local networks and are not allowed on the
Internet: 10.0.0.0 to 10.255.255.255, 172.16.0.0 to 172.31.255.255, and 192.168.0.0 to
192.168.255.255.
The RCM3900 uses a 10/100-compatible Ethernet connection. The RJ-45 connectors are
similar to U.S. style telephone connectors, except they are larger and have 8 contacts.
An alternative to the direct connection is a connection using a hub. The hub relays packets
received on any port to all of the ports on the hub. Hubs are low in cost and are readily
available. The RCM3900 uses 10/100 Mbps Ethernet, so the hub or Ethernet adapter
should be a 10/100 Mbps unit.
In a corporate setting where the Internet is brought in via a high-speed line, there are typi-
cally machines between the outside Internet and the internal network. These machines
include a combination of proxy servers and firewalls that filter and multiplex Internet traf-
fic. In the configuration below, the RCM3900 could be given a fixed address so any of the
computers on the local network would be able to contact it. It may be possible to configure
the firewall or proxy server to allow hosts on the Internet to directly contact the controller,
but it would probably be easier to place the controller directly on the external network out-
side of the firewall. This avoids some configuration complications by sacrificing some
security.
RabbitCore RCM3900 User’s Manual
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