A channel is any technology that has made a media connection to asterisk. In other words, if you have an analogue line connected to voicemail, or you are making a SIP call, those sorts of things happen on channels. Other types of connections (such as a connection to the manager interface) would not be considered channels. Generally, a channel has to involve some sort of audio connection.
A trunk is a tricker term, in that it means different things to different people in different contexts. In normal telecom terms, a trunk is used to connect two switches together. In this sense, some channels in Asterisk could be considered as trunks, but technically they are nothing more than channels. This actually underscores a very interesting part of the nature of asterisk, in that it treats all channels as equal. In most PBXs, there are trunks, and there are stations, and the features and functions of each are quite different. This equality is one of the things that make asterisk so compelling, however it also means that some traditional telecom terms don't quite fit. "Trunking" is one such term. In asterisk terminology, trunking is a technology within the IAX protocol that allows multiple media streams to be transmitted in a single packet, thus cutting down on overhead. I am not aware of it being used formally anywhere else within asterisk. Probably when you hear the term used, it is likely that it is referring to a circuit that connects to another switch (such as the central office), but that might not always be the case. Personally I think that I would ask "which trunks?". I would then expect "the PSTN trunks", or "the VoIP trunks" (both of which are going to be groups of channels in asterisk), or "the IAX trunks", at which point I can be clever and ask "how many The type of trunk that confuses me the most is "the SIP trunk". The reason this one troubles me, is that I am pretty sure that there is no such thing. Sure, a SIP connection can be used for the purpose of trunking two systems together, but as far as the protocol is concerned, there is no "trunking" happening between the systems. I guess to answer your question, you could say that groups of asterisk channels can be configured in such a way that they provide a trunking facility. Whew. I'll shut up now . . . Jim > -----Original Message----- > From: David LEWIS [mailto:[EMAIL PROTECTED] > Sent: July 28, 2007 8:16 PM > To: [email protected] > Subject: [on-asterisk] A trunk/channel/line > > What is the difference between a trunk, a channel? > > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.476 / Virus Database: 269.10.22/923 - Release > Date: 27/07/2007 6:01 PM > > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: 269.10.22/923 - Release Date: 27/07/2007 6:01 PM --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
