Beckhoff EL6601 Documentation page 138

Application samples
• "Ping" works
Observation of network traffic
Experienced users can observe and evaluate the network traffic using a network sniffer, such as
Wireshark.
Notice on Operating system Windows CE/embedded
Under Windows CE IP Routing must be set in the CX Configuration Dialog (see Fig. "Setting IP
Routing in Windows CE")
The entry "TCP/IP Settings" -> "IP Routing" sets the Registry-Key "IPEnableRouter"= 1 under
[HKEY_LOCAL_MACHINE\Comm\Tcpip\Parms]
Restart required.
See also Microsoft Developer Network: Routing for IPv4 - Explanation on Routing.
Ordinarily the Routing table is automatically maintained, if necessary routes will still have to be
added with "Route Add" command, see also Windows XP/7 etc.
Windows CE does not support some Routing protocols such as RIP or OSPF.
Fig. 175: Setting "IP Routing" in Windows CE
Network with DHCP address assignment
A connection between the PCs C and A (or the network) is not possible.
Explanation: Computers (A) and (B) receive their IP addresses from the DHCP server if the Ethernet ports
are configured accordingly. One possible sequence is as follows (see RFC1541 and RFC2131):
• A newly connected PC sends a DHCPDISCOVER message with its MAC address via MAC Broadcast
to all other network devices
• The DHCP server offers the requesting device one or more IP addresses in the DHCPOFFER
message
• The requesting PC selects an IP address and answers via MAC Broadcast with a DHCPREQUEST
message to the DHCP server
• The DHCP server confirms the selection with a DHCPACK message.
138 Version: 4.2 EL6601, EL6614