The move from traditional systems like the public-switched telephone network (PTSN) is in progress, and some enterprises have moved to session initiation protocol (SIP) as the preferred method to facilitate voice communications over the Internet. SIP Trunking offers some advantages over legacy systems, most notably scalability, reliability, and reduced costs. SIP Trunking also has its own set of challenges, especially where security is concerned. The SIP Trunk connects your legacy on-premises PBX with the PSTN through the Internet, rather than copper wires. It can also provide many new cloud-based.
SIP Trunking Features

According to sip.us, the most popular features of SIP Trunking include toll-free numbering and multiple DID options, local numbers for remote offices, access to call detail records, e911, voicemail, and disaster recovery. These features are often managed from the cloud, so they can be controlled, edited, and managed off-site.
Advantages
Because SIP Trunking does not require a significant capital expenditure. It can immediately begin to reduce costs while also maintaining the features customers have with their local PBX. This rapid ROI enables fast geographic growth, because not only can funds become more available, but the nature of cloud-based networks mean that remote locations can be set up quickly and added to your existing network.
Since SIP Trunking is delivered over Internet Protocol, you can get more call concurrency over modern broadband when compared to old style telephone connections. In addition to this, you can enjoy dramatically reduce call costs.
By adding more unified communication functions, your business can increase productivity with mobility applications, easy scalability when hiring new employees, and an easy-to-use interface that doesn’t take a CCNA to change call forwarding protocols.
Deployment
When a SIP Trunk is deployed, a few decisions will need to be made from an organizational standpoint. Some will choose a centralized architecture with the trunk and PBX located at one spot, with other trunks feeding into the central point, or the business could select to go with a more distributed network
Security
Another important aspect that is often ignored during SIP trunking deployment is security. It is much harder to make a deployment secure after the fact. This is the scenario that most organizations fall into. End to end encryption, real time monitoring software, session border controllers, firewalls and other hardware are all various tools that can be deployed in order to make the network more secure.
Best Practices
There are a few best practices that are generally followed in order to enhance the quality and reliability of cloud-based systems. When the most recommended activities is to set up QOS settings on the various hardware so the voice calls get priority during peak traffic. This will make the difference between clear calls and dropped calls. Another best practice relates to security. Account credentials and passwords need to be guarded securely to avoid toll fraud.
Once your SIP trunk is set up and ready to go, there’s not much in the way of general maintenance to perform. You can leverage your knowledgeable employees to change configuration, implement additional features, and help with the security of the system. But for the most part, employees will not need to change their day-to-day activities.