[asterisk-users] RTP Read too short with T.38

[Irmantas]

I have the following situation:


SIP Provider -> My asterisk -> SPA2102.

Time to time I recieve a lot of warnings on asterisk CLI with RTP Read too 
short, after T.38 session established.

It hapens only in one direction when fax trasmited from provider to SPA2102.
I noticed, that asterisk did not pases one packet, that i include below. 
Asterisk reports warning , and drops that frame instead of passing it to SPA 
adapter.

Asterisk version 1.4.10.1


No.     Time        Source                Destination           Protocol 
Info
   1021 43.015431   80.80.80.80          90.90.90.90         T.38     UDP: 
UDPTLPacket Seq=00001  t30ind: cng

Frame 1021 (60 bytes on wire, 60 bytes captured)
    Arrival Time: Sep 19, 2007 07:31:23.630092000
    Time delta from previous packet: 0.499966000 seconds
    Time since reference or first frame: 43.015431000 seconds
    Frame Number: 1021
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Protocols in frame: eth:ip:udp:t38
    Coloring Rule Name: UDP
    Coloring Rule String: udp
Ethernet II, Src: Intel_c4:22:40 (00:04:23:c4:22:40), Dst: 00:19:db:34:aa:0f 
(00:19:db:34:aa:0f)
    Destination: 00:19:db:34:aa:0f (00:19:db:34:aa:0f)
        Address: 00:19:db:34:aa:0f (00:19:db:34:aa:0f)
        .... ...0 .... .... .... .... = Multicast: This is a UNICAST frame
        .... ..0. .... .... .... .... = Locally Administrated Address: This 
is a FACTORY DEFAULT address
    Source: Intel_c4:22:40 (00:04:23:c4:22:40)
        Address: Intel_c4:22:40 (00:04:23:c4:22:40)
        .... ...0 .... .... .... .... = Multicast: This is a UNICAST frame
        .... ..0. .... .... .... .... = Locally Administrated Address: This 
is a FACTORY DEFAULT address
    Type: IP (0x0800)
    Trailer: 00000000000000000000
Internet Protocol, Src: 80.80.80.80 (80.80.80.80), Dst: 90.90.90.90 
(90.90.90.90)
    Version: 4
    Header length: 20 bytes
    Differentiated Services Field: 0x34 (DSCP 0x0d: Unknown DSCP; ECN: 0x00)
        0011 01.. = Differentiated Services Codepoint: Unknown (0x0d)
        .... ..0. = ECN-Capable Transport (ECT): 0
        .... ...0 = ECN-CE: 0
    Total Length: 36
    Identification: 0x49c4 (18884)
    Flags: 0x00
        0... = Reserved bit: Not set
        .0.. = Don't fragment: Not set
        ..0. = More fragments: Not set
    Fragment offset: 0
    Time to live: 61
    Protocol: UDP (0x11)
    Header checksum: 0xffde [correct]
        Good: True
        Bad : False
    Source: 80.80.80.80 (80.80.80.80)
    Destination: 90.90.90.90 (90.90.90.90)
User Datagram Protocol, Src Port: 35550 (35550), Dst Port: 12166 (12166)
    Source port: 35550 (35550)
    Destination port: 12166 (12166)
    Length: 16
    Checksum: 0x0f73 [correct]
ITU-T Recommendation T.38
    Stream setup by SDP (frame 760)
        Stream frame: 760
        Stream Method: SDP
    UDPTLPacket
        Sequence number: 1
        IFPPacket
            Type of msg: t30-indicator (0)
                T30 indicator: cng (1)
        Error recovery: secondary-ifp-packets (0)
            Secondary IFPPackets
                Item 0
                    IFPPacket
                        Type of msg: t30-indicator (0)
                            T30 indicator: no-signal (0)