Wireshark · Wireshark-users: [Wireshark-users] question about docsis dsa packet marked as malformed on decode

["Mike Oliveras" <mike.oliveras@xxxxxxxxx>]

I have a capture of a docsis dsa packet that is marked as malformed by
wireshark 0.99.6.  Can anyone give me any insight as to what the
problem might be?  The packet was captured from an docsis cable
network with Filtronics Sigtek analyzer.  I have attached both the
pcap file and a text decode of the packet.

Regards,

Mike

Attachment: malformed-dsc-message.pcap
Description: Binary data

No.     Time        Source                Destination           Protocol Info
      2 0.009421    Motorola_c7:19:8c     Cisco_01:70:54        DOCSIS MGMT Dynamic Service Change Request Tran-id = 112[Malformed Packet]

Frame 2 (209 bytes on wire, 209 bytes captured)
    Arrival Time: Nov  7, 2007 17:10:59.152012000
    [Time delta from previous captured frame: 0.009421000 seconds]
    [Time delta from previous displayed frame: 0.009421000 seconds]
    [Time since reference or first frame: 0.009421000 seconds]
    Frame Number: 2
    Frame Length: 209 bytes
    Capture Length: 209 bytes
    [Frame is marked: False]
    [Protocols in frame: docsis:docsis_mgmt:docsis_dscreq:docsis_tlv]
DOCSIS
    11.. .... = FCType: MAC Specific (0x03)
    ..00 001. = FCParm: Mac Management Message (0x01)
    .... ...0 = EHDRON: Extended Header Absent
    MacParm: 0x00
    Length after HCS (bytes): 203
    Header check sequence: 0xae86
Mac Management
    Destination Address: Cisco_01:70:54 (00:03:6c:01:70:54)
    Source Address: Motorola_c7:19:8c (00:1a:de:c7:19:8c)
    Message Length - DSAP to End (Bytes): 185
    DSAP [0x00]: 0x00
    SSAP [0x00]: 0x00
    Control [0x03]: 0x03
    Version: 2
    Type: Dynamic Service Change Request (18)
    Reserved [0x00]: 0
DSC Request
    Transaction Id: 112
    TLV Data
        24 Upstream Service Flow (Length = 37)
            .2 Service Flow Id: 16891
            .6 QOS Parameter Set: Perform admission control add apply to admitted set (0x02)
            .16 Request/Transmission Policy: 0x0000017f
                Service flow MUST NOT use "all CMs" broadcast request opportunities
                Service flow MUST NOT use priority multicast request opportunities
                Service flow MUST NOT use Request/Data opportunities for requests
                Service flow MUST NOT use Request/Data opportunities for data
                Service flow MUST NOT use piggy back requests with data
                Service flow MUST NOT concatenate data
                Service flow MUST NOT fragment data
                Service flow MUST drop packets that do not fit in the UGS size
            .15 Scheduling Type: Unsolicited Grant Service (0x00000006)
            .20 Nominal Grant Interval (usec): 20000
            .21 Tolerated Grant Jitter (usec): 800
            .19 Unsolicited Grant Size (bytes): 227
            .22 Grants Per Interval: 1
        25 Downstream Service Flow (Length = 34)
            .2 Service Flow Id: 16946
            .6 QOS Parameter Set: Perform admission control and activate; Apply to admitted and active sets (0x06)
            .7 Traffic Priority: 5
            .10 Minimum Traffic Rate (bps): 87200
            .11 Assumed Min Reserved Packet Size: 218
            .8 Maximum Sustained Traffic Rate (bps): 87200
            .9 Maximum Burst (bps): 1522
        22 Upstream Packet Classifier (Length = 53)
            .2 Classifier ID: 46
            .4 Service Flow ID: 16891
            .5 Rule Priority: 128
            .6 Activation State: Inactive
            .7 DSC Action: DSC Replace Classifier (1)
            9 IP Classifier (Length = 32)
                ..2 IP Protocol: 17
                ..3 Source Address: 10.103.1.66 (10.103.1.66)
                ..4 Destination Address: 10.103.1.65 (10.103.1.65)
                ..7 Source Port Start: 49152
                ..8 Source Port End: 49152
                ..9 Dest Port Start: 49152
                ..10 Dest Port End: 49152
        23 Downstream Packet Classifier (Length = 45)
            .2 Classifier ID: 47
            .4 Service Flow ID: 16946
            .5 Rule Priority: 128
            .6 Activation State: Active
            .7 DSC Action: DSC Replace Classifier (1)
            9 IP Classifier (Length = 24)
                ..2 IP Protocol: 17
                ..3 Source Address: 10.103.1.65 (10.103.1.65)
                ..4 Destination Address: 10.103.1.66 (10.103.1.66)
[Malformed Packet: DOCSIS TLVs]