Component Network over IP (CN/IP)

CN/IP is defined in standard EIA/CEA-852. It is used to transport component network frames such as LON over UDP or TCP.

A word of warning: The CN/IP dissector was implemented in order to dissect LON traffic. The dissector was not tested with real CN/IP traffic, but with packets I generated myself.

History

Protocol dependencies

• UDP: Typically, CN/IP uses UDP as its transport protocol. The well known port for CN/IP traffic is 1628.

• TCP: CN/IP can also use TCP as its transport protocol. The port number is the same.

Example traffic

Frame 10611: 70 bytes on wire (560 bits), 70 bytes captured (560 bits)
Ethernet II, Src: 00:00:00:00:00:00 (00:00:00:00:00:00), Dst: 00:00:00:00:00:00 (00:00:00:00:00:00)
Internet Protocol Version 4, Src: 127.0.0.1 (127.0.0.1), Dst: 127.0.0.1 (127.0.0.1)
User Datagram Protocol, Src Port: 43769 (43769), Dst Port: 1628 (1628)
Component Network over IP
    Packet length: 28
    Version: 1
    Packet type: Data Packet (0x01)
    Ext. Header Size: 0
    Protocol Flags: 0
        ..0. .... = Protocol Flags: 0
        ...0 0000 = Protocol Code: 0
    Vendor Code: 0
    Session ID: 1804289383
    Sequence Number: 14034
    Time Stamp: 0
Local Operating Network

Wireshark

The CN/IP dissector currently only supports dissection of data frames.

Preference Settings

No preference setting at this time.

Example capture file

• SampleCaptures/eia709.1-over-eia852.pcap

Display Filter

A complete list of display filter fields can be found in the display filter reference

• Show only the CN/IP based traffic:

   cnip 

Capture Filter

You cannot directly filter CN/IP protocols while capturing. However, if you know the UDP port used (see above), you can filter on that one.

• Capture only the CN/IP traffic over the default port (1628):

   udp port 1628 

External links

• Unfortunately the standard is not freely available

Discussion