RabbitCore RCM2000 Series, Руководство по началу работы

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24 RabbitCore RCM2200
4.2 Running TCP/IP Sample Programs
We have provided a number of sample programs demonstrating various uses of TCP/IP for
networking embedded systems. These programs require that the user connect his PC and
the RCM2200 board together on the same network. This network can be a local private
network (preferred for initial experimentation and debugging), or a connection via the
Internet.
Obtaining IP addresses to interact over an existing, operating, network can involve a num-
ber of complications, and must usually be done with cooperation from your ISP and/or
network systems administrator (if your company has one). For this reason, it is suggested
that the user begin instead by using a direct connection between a PC and the RCM2200
board using an Ethernet crossover cable or a simple arrangement with a hub. (A crossover
cable should not be confused with regular straight through cables.) The hub and a wide
variety of cables can also be purchased from a local computer store.
In order to set up this direct connection, the user will have to use a virgin PC (right out of
the box), or disconnect a PC from the corporate network, or as yet another approach 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. Mobile PCs, such as laptops, are
designed to be connected and disconnected, and will present the least problem. 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 corporate 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.
RCM2200
User’s PC
Ethernet
crossover
cable
Direct Connection
(Network of 2 computers)
RCM2200
Hub
Ethernet
cables
To additional
network
elements
Direct Connection Using a Hub
Board
Board