Summary: | ASTERISK-17284: T38 passthrough doesn't work in glare reinvite situation | ||
Reporter: | mdu113 (mdu113) | Labels: | |
Date Opened: | 2011-01-25 16:02:55.000-0600 | Date Closed: | |
Priority: | Minor | Regression? | No |
Status: | Open/New | Components: | Channels/chan_sip/T.38 |
Versions: | Frequency of Occurrence | ||
Related Issues: | |||
Environment: | Attachments: | ( 0) debug.log | |
Description: | Have the following situation: 000011206003 (cisco 1751+fxs with t38 enabled) <-> asterisk <-> sipp1 (ITSP) ITSP is using Cisco AS5400 to terminate sip calls to PSTN and has T38 enabled The problem is that both cisco devices detect fax tones (and send T38 reinvites) almost concurrently and that seems to confuse asterisk. I see the following logged on the console: [Jan 25 16:03:21] WARNING[5956] chan_sip.c: Failed to read an alternate host or port in SDP. Expect audio problems [Jan 25 16:03:21] WARNING[5956] chan_sip.c: Failed to set an alternate media source on glared reinvite. Audio may not work properly on this call. When it happens fax 100% fails. When it doesn't happen fax works very reliably ****** ADDITIONAL INFORMATION ****** Attached is asterisk's debug.log. I've made the following sip messaging diagram: 000011206003 asterisk sipp1 -> INVITE <- 407 Proxy Authentication Required -> ACK -> INVITE with auth <- 100 Trying INVITE -> 100 Trying <- 183 Session Progress <- <- 183 Session Progress 200 OK <- ACK -> <- 200 OK -> ACK INVITE with T38 (by sipp1) <- 100 Trying -> <- INVITE with T38 -> INVITE with T38 (by 000011206003) [Jan 25 16:03:21] WARNING[5956] chan_sip.c: Failed to read an alternate host or port in SDP. Expect audio problems [Jan 25 16:03:21] WARNING[5956] chan_sip.c: Failed to set an alternate media source on glared reinvite. Audio may not work properly on this call. <- 491 Request Pending -> 491 Request Pending <- ACK -> ACK <- INVITE without T38 -> 100 Trying -> 200 OK without T38 <- ACK -> INVITE with T38 <- 100 Trying <- 200 OK with T38 -> ACK Also cisco debugging (debug fax relay t30 all-level-1) in this case shows that fax negotiation fails: Jan 25 16:09:14: 2/2 96067571 fr-entered=10(ms) timestamp=96075370 fr-msg-det TSI timestamp=96076070 fr-msg-det DCS timestamp=96086030 fr-msg-det TSI timestamp=96086720 fr-msg-det DCS Successful fax debugging looks like the following: Jan 25 16:01:00: 2/2 95573302 fr-entered=10(ms) timestamp=95579990 fr-msg-tx CSI timestamp=95580680 fr-msg-tx DIS timestamp=95582460 fr-msg-det TSI timestamp=95583150 fr-msg-det DCS timestamp=95589140 fr-msg-tx CFR timestamp=95630240 fr-msg-det EOP timestamp=95632830 fr-msg-tx MCF timestamp=95634540 fr-msg-det DCN | ||
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