SIP Providers

SIP servers and PBX

SIP Handling

Selecting a SIP provider depends on various factors.
SIP trunks can deliver audio different;y
Direct media, audio through proxy and peer audio are all handled differently.
Depending on your internet provider, bandwidth availability and cost are things to consider. How will your on-premise or cloud hosted PBX be affected by any of these methods of delivery?

Are you currently using VOIP? Are you getting the experience you had expected?
Are you getting all the features you asked for?
Are you saving what you thought you would be?
A1 Computers is ready to diagnose the problem.

SIP servers and PBX

SIP Basics

  • SIP - (Session Initiated Protocol) Creates a modular session between 2 points for communication with audio, video and/or chat session
  • Proxy Audio - A proxy server primarily plays the role of routing ex. PBX ===> Proxy ===> Host

Although this method can cause latency issues depending on your available bandwidth it doesn't usually require specific firewall configuration and most of the security is handled by the TISP

  • Direct Media - Using Direct Audio for your calls eliminates a potential point of failure or latency in your audio stream ex. PBX ==> Host

this method has specific requirements from the user to properly configure firewall traffic and secure the route

  • RTP/SRTP and RTCP - (Remote Transfer) SIP is extended by adding new header lines or message bodies that may be used by different vendors to serve different purposes, thus risking compatibility problems, and causing the dreaded one-way or worse no-way audio
  • DNSSRV - Used as a method of fail-over, if your host has multiple servers and is ready for disaster recovery you should configure DNS SRV records on your PBX or SIP device so that manual configuration is not necessary each time there is an outage on a particular server. better yet have 2 providers ready to deliver calls to each other.
  • T38 - The FAX protocol, this has not been known to be stable in the SIP world, if FAX is a mission critical requirement to you, we recommend keeping your POTS phone line for this service.

SIP Trunks

Different carriers deliver SIP differently please have a look at the above carriers to find out how.
While VOIP can be a cost effective decision for your home or business all variables should be considered.
We are trusted professionals that can make VOIP a productive appliance in your network environment.

We are dedicated to proper network evaluation before service can be designed or installed
Contact us

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