NSE: Difference between revisions

Latest revision as of 13:41, 28 March 2018

NSE (Named Signaling Events) is a proprietary protocol to switch from voice to passthrough for fax/modem communication without involving SIP. It uses a proprietary event, based on NTE (Named Telephone Events). NTE is not proprietary, but NSE is.

TelcoBridges and NSE

We currently support NSE events:

192 (switch to passthru)
193 (disable echo)
194 (switch back to voice)

This adds a new SIP SDP entry that looks like this for initial negotiation:

a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194

The system does not send a SIP re-invite, but instead will send this NSE event 192.

Call Flow

Configuration

Toolpack v2.7: NSE configuration

References

@@ Line 1: / Line 1: @@
-According to Wikipedia, "T.38 fax relay standard was devised in 1998 as a way to permit faxes to be transported across IP networks between existing Group 3 (G3) fax terminals. T.4 and related fax standards were published by the ITU in 1980, before the rise of the internet. In the late 90s, [[VoIP]], or Voice over IP, began to gain ground as an alternative to the conventional [[PSTN|Public Switched Telephone Network]]. However, because most VoIP systems are optimized (through their use of bandwidth-saving compression) for voice rather than data calls, conventional fax machines worked poorly or not at all on them due to the network impairments such as delay, jitter, packet loss, and so on. Thus, some way of transmitting fax over IP was needed.
+NSE (Named Signaling Events) is a proprietary protocol to switch from voice to passthrough for fax/modem communication without involving SIP. It uses a proprietary event, based on NTE (Named Telephone Events). NTE is not proprietary, but NSE is.
+== TelcoBridges and NSE ==
+We currently support NSE events:
+<pre>
+(switch to passthru)
+(disable echo)
+(switch back to voice)
+</pre>
+This adds a new SIP SDP entry that looks like this for initial negotiation:
+<pre>
+a=rtpmap:100 X-NSE/8000
+a=fmtp:100 192-194
+</pre>
+The system does not send a SIP re-invite, but instead will send this NSE event 192.
+===Call Flow===
+[[Image:NSE_call_flow.png| ]]
-== TelcoBridges and NSE ==
+== Configuration ==
-TelcoBridges provides native support for the T.38 fax relay standard.
+*[[Toolpack v2.7: NSE configuration]]
 == References ==
-*[http://en.wikipedia.org/wiki/T.38 Wikipedia article]
+*[http://tools.ietf.org/html/rfc2833 RFC 2833]
+*[https://supportforums.cisco.com/docs/DOC-1381 list of NSE events]
 [[category:Glossary]]