LonTalk (LON)

Apart from building control LonTalk is used in industry automation, at railway stations, for on-train telemetry, in traffic management, and smart meters.

History

The LonTalk protocol was originally developed by Echelon Inc. in 1988. In 1999 it was approved as ANSI standard EIA/CEA-709.1.

Protocol dependencies

CNIP: LonTalk can be transmitted over a variety of media, but Wireshark can only capture LON traffic when it is encapsulated in UDP or TCP packets. CNIP is the encapsulation protocol used for LonTalk.

Example traffic

Frame 3057: 74 bytes on wire (592 bits), 74 bytes captured (592 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
Local Operating Network
    PPDU: 0x01
        0... .... = Priority: 0
        .0.. .... = Alt path: 0
        ..00 0001 = Delta BL: 1
    NPDU: 9, PDU format: TPDU, Address format: Unicast (2a)/Multicast (2b), Domain length: 8 bit
        00.. .... = version: 0x00
        ..00 .... = PDU format: TPDU (0x00)
        .... 10.. = Address format: Unicast (2a)/Multicast (2b) (0x02)
        .... ..01 = Domain length: 8 bit (0x01)
    Address type 2a (unicast)
        Source subnet: 0x01
        .000 0101 = Source node: 0x05
        Destination subnet: 0x01
        .000 0011 = Destination node: 0x03
    Domain: 01
    TDPU: 0x02, TPDU type: ACKD
        0... .... = Auth: 0x00
        .000 .... = TPDU type: ACKD (0x00)
        .... 0010 = Transaction number: 0x02
    1... .... .... .... = Network Variable: 0x0001
        .0.. .... .... .... = NV direction: 0x0000
        ..00 0010 1001 1111 = NV selector: 0x029f
    Data (2 bytes)

0000  00 c4                                             ..
        Data: 00c4
        [Length: 2]

Wireshark

The LON dissector decodes all types of LON packets. Multicast traffic is not well tested and statistics collection as well as conversation tracking is missing.

Preference Settings

Preferences are not implemented in the LonTalk dissector.

Example capture file

SampleCaptures/eia709.1-over-eia852.pcap

Display Filter

Show only the LON based traffic:

lon

Only display Network variables with ID 0x375:

lon.nv == 0x375

Capture Filter

LonTalk can only be captured as part of a CN/IP packet.

External links

LonTalk is specified in EIA/CEA-709.1
Echelon Inc. - http://www.echelon.com/
Wikepedia entry about LonTalk at http://en.wikipedia.org/wiki/LonTalk

Discussion

Imported from https://wiki.wireshark.org/Protocols/CEA-709.1 on 2020-08-11 23:19:12 UTC