6F8C0904 13
1.6 Software Configuration
1
When EN311 receives data, EN311 notifies data reception to S controller regard-
less of a status of the PSH bit.
• Reset packet (packet which the RST bit is set to ON)
If the firmware of EN311 is after Revision I, transmission/reception of a reset
packet is possible for EN311. EN311 firmware carries out transmission of a reset
packet in conformity with TCP agreement. A reset packet cannot be transmitted
by S controller user program.
(2) UDP (User Datagram Protocol)
Transfers data with the remote node in datagram units. Provides high-speed
transfers since a connection is not used, but does not have control functions that
assure reliability, as does TCP. Thus it requires support from a higher level protocol.
The EN311 supports the following function:
• UDP checksum function.
(3) IP (Internet Protocol)
Sends and receives data in the datagram format. Sends data in datagram units to the
remote node according to the IP address.
The EN311 supports the following functions:
• Data fragmentation and reassemble
• Direct routing
• Broadcast
• Indirect routing --- Default routing
The EN311 does not support the multicast functions:
Although the EN311 physical layer structure conforms to the ISO8802-3 standard, it
adopts DIX standard frames as the data link frames (the IP datagram send/receive
frames). See Figure 6-8.
(4) ARP (Address Resolution Protocol)
Searches for a node MAC address (Ethernet address) that has a specified IP
address.
(5) ICMP (Internet Control Message Protocol)
Reports IP packet errors and verifies the state of the IP network.
The EN311 supports the following functions:
• Echo request/reply
• Timestamp request/reply
• Information request
• Destination unreachable
• Source quenches
• Redirect
• Time exceeded for a datagram
• Parameter problem on datagram
• Address mask request
The EN311 does not support the following functions:
• Information reply
• Address mask reply
To Next Page
Loading...
Need help?
General
