Transcript
Configuration in General
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Dialogic® Brooktrout® Configuration Tool FoIP: Advanced Mode only (wizard mode in future SDK) Creates the configuration files – btcall.cfg: global user parameters – callctrl.cfg: call control
Can be used to turn on “Brooktrout logging” portion of Brooktrout Configuration Tool: – Bfv api debug log: media => see btcall parameters – ECC call control trace: call control => see callctrl parameters
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Selection of IP Stack At first time launch of configtool: IP stack preference box Afterwards: in Configtool menu: Options -> Configure IP Stack Select SIP or H323 stack (not both)
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Media_Renegotiate_Delay_Outbound & _Inbound
Configurable value in Config Tool – Starting in Dialogic® Brooktrout® SDK 5.2, default _outbound value is -1 When we place outbound call, we will never send the re-INVITE or RequestMode to re-establish session for T.38 when value is -1 We will wait for CUCM or gateway to do so; if it does not, call will time out and ultimately fail Why do this? CNG sent out over RTP session, if we switch to T.38 mode too soon the remote end will not hear CNG tone – If receiving device needs to hear it before switching to fax mode, call will fail MFP (Multi Function Printer/Product/Peripheral ) – Way of ensuring that the remote end only switches to T.38 when it is truly ready When doing initial setup and testing, may want to set this value to positive integer to see if remote network side supports T.38 – If we send SIP re-INVITE or H.245 RequestMode and we are rejected, that indicates network side is not configured for T.38 – inbound value is some positive integer value in X000’s (milliseconds) On our receiving a call, we will broadcast CED tone, then we will send the reINVITE or H.245 RequestMode to switch to T.38
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Note on Outbound Call to Combined Phone-Fax Device PSTN
IP
CNG CED + FSK GW
Se ds S Sends SIP re-INVITE e or H.323 RequestMode to change from VOIP to T.38
Callctrl.cfg: media_renegotiate_delay_outbound=-1
Default from Brooktrout SDK 5.2 on – When troubleshooting: try -1 and values like 2000, 4000 – Test if remote network side can support T.38 connection www.dialogic.com
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Wireshark (Ethereal) Basics of Wireshark Sample Trace Files Graph call legs www.wireshark.org
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Download Wireshark (Formerly Ethereal) Or now http://www.wireshark.org/ Download the latest released utility Install components – Take all the defaults – Definitely install WinPcap • Output saved as .pcap pcap file • Any .pcap viewer can read • Wireshark has user-friendly features
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Wireshark – Main Window 1. Main toolbar
3. Packet list
2. Filter toolbar
4. Packet Details
6. Status bar
5. Packet Bytes
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Start Capturing Live Data
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View Only the SIP Packets
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INVITE Message
INVITE Message Header
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INVITE Message Body
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100 TRYING Message
SESSION PROGESS Message
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200 OK
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ACK
RE-INVITE
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OK
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Show H.323 Trace
H.245 Messages
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Graphing Voice/Fax Calls Easy way to quickly see the call flow
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Wireshark “Telephony -> VoIP Calls -> Graph”
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Listening to Audio Portion of Call
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Audio From “Graph” choose “Player” “Decode” Check boxes for sending and receiving side, click “Play” – Will hear audio of the call up till the point of T.38 switchover – Can tell if a human voice answers, if busy tone is returned, etc
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T.38 Troubleshooting
Voice Call establishment Identification and selection of capabilities (V.21, 300 baud, Low Speed) Training Check T.4 Fax Transmission V.22bis (1200 – 2400 Bps) V.27 (2400 – 4800 Bps) V.29 (4800 – 9600 Bps) V.17 (9600 – 14400 Bps) Confirmation of page transmission (V.21, 300 baud, Low Speed) Call Release (V.21, 300 baud, Low Speed)
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