carriers-sip
SIP peer
A SIP peer is any single phone or trunk the server knows how to talk to, with its own name, credentials, and connection settings.
A SIP peer is the server's word for one endpoint it can exchange calls with. That endpoint might be a single agent phone, or it might be a connection to your carrier. Each peer is a named entry in the server's configuration that spells out how to reach it: the address, the credentials, which Codec choices are allowed, and how calls should be routed. Think of it as one contact card per device or link.
There are broadly two kinds of peer. A phone peer is a device an agent uses, usually tied to a VICIdial Extension and verified through Phone registration. A trunk peer is the line to the outside world, set up as a SIP trunk so the dialer can place calls to real phone numbers. Both are configured the same way under the hood, just with different settings.
How peers prove who they are
A peer authenticates in one of two ways. Phones that move around register with the SIP registrar using a username and password, so the server always knows their current location. Carrier links more often use IP authentication, where the server trusts a fixed address and skips the login step entirely. Getting this right is the difference between a peer that connects reliably and one that silently fails.
When you read server logs, each active call ties back to a peer and rides on its own Channel. If calls to one destination keep failing, the peer definition is the first thing to check, because a single wrong setting there blocks every call through it. Keep peer names clear so it is obvious which phone or carrier each one represents.
On a busy dialer you can end up with a lot of peers: one per agent phone plus one or more carrier links. Keeping them tidy pays off when something breaks at three in the afternoon and you need to find the culprit fast. A few habits help. Name phone peers after the extension or agent they belong to, name trunk peers after the carrier, and write down which Codec each carrier expects so you do not have to rediscover it under pressure. If a peer represents a SIP trunk that handles a chunk of your traffic, watch it closely, because problems there hit many calls at once rather than one stray phone. Treating each peer as a small, clearly labeled contact card is what keeps a growing setup understandable instead of a tangle.
Related terms
Channel
A single call path on your trunk, where each live call uses exactly one channel, so the channel count is the cap on how many calls can run at once.
Extension
An extension is a short internal number that identifies a single phone, agent, or destination inside a PBX so calls can be routed to it.
IP authentication
A way for your carrier to recognize your dialer by its public IP address instead of a username and password, so calls connect without login credentials.
Phone registration
The process where a softphone or SIP device announces itself to VICIdial so the server knows where to send the agent's calls.
SIP registrar
A SIP registrar is the part of the phone system that records where each extension currently is, so incoming calls know which device to ring.
SIP trunk
A virtual phone line over the internet that connects your dialer to a carrier, letting you place and receive many calls at once without physical wires.