VoIP Considerations

Voice over Internet Protocol (VOIP) was initially developed to reduce the cost of long-distance and international calling.  At the time of its development in 1995, any phone call outside the caller’s local calling area would incur per-minute costs from the caller’s local phone service provider.  The only alternative was to purchase a costly service bundle that included local exchange and toll calling for a single charge (FCC, n.d.)  Such service bundles would allow for an expanded calling area but did not include long-distance toll calls and international calls.  The development of VOIP allowed consumers and businesses to bypass the traditional phone providers to use their computers instead of landline phones.  The primary complaint of VOIP calls in that era was the disappointing voice quality resulting from the low bandwidth provided using Digital Subscriber Line (DSL) over traditional twisted-pair copper phone lines and other similar early network configurations.  As the data networks evolved to provide higher bandwidth capabilities, the use of VOIP expanded and became a widely accepted solution.  The introduction of Skype in 2003 was a “real world” use of VOIP that propelled the advancement of VOIP technology.  By 2005, Skype added video chat and other features that further drove its growth.  Session Initiation Protocol (SIP) is a protocol that is used in most implementations of VoIP).  SIP is used to establish the communication session, manage the signaling and terminate the connection.  SIP, however, is not limited to VoIP applications.  Along with voice, SIP is used for other communications, including video and chat.

Advantages of VoIP

While the development of VoIP initially had the objective of reducing calling expenses, the technology has enabled many new communications capabilities and flexibility that is not feasible using traditional telephony technology.  However, cost reduction remains a primary advantage of VoIP when compared to other technologies.

Portability is another advantage of VoIP technology.  Since the communications sessions are transmitted over the Internet, VoIP can be used anywhere that there is an Internet connection.  Many businesses who use VoIP have taken advantage of this advantage during the COVID pandemic.  Since much of the workforce was required to shift from working in offices to working from home, VoIP was instrumental in this transition.  Communications using VoIP allow the employees to communicate from home in the same manner, they did from the office.  VoIP made this shift to remote work relatively seamless.  Without VoIP, such a rapid work environment change would not have been feasible.  The portability of VoIP has been a driving force in the ability for employees to work in decentralized locations all over the world.

VoIP services also offer more features than traditional telephony services.  All conventional services are available, including call forward, call waiting, caller ID, call transfer, etc.  VoIP, however, can offer services such as call queues and the ability to place callers on hold without the extra expense of an in-house private branch exchange (PBX) system and multiple phone lines.  Beyond this, VoIP providers integrate conference calling, video conferences, chatting, and other types of communications into their unified communications offerings.

As stated above, the adoption of VoIP was slow due to bandwidth constraints in the 1990s.  Bandwidth constraints are no longer an issue in many parts of the world.  Today, one of the advantages of VoIP is that it provides superb voice quality that is as good or better than traditional telephony services.

Disadvantages of VoIP

A disadvantage of VoIP is that it relies on a computer or device that requires external power.  A power outage will disrupt your communication until power is restored.  This is why many businesses and some homes continue to have Plain Old Telephone Service (POTS) lines available as a backup to VoIP.  POTS lines do not require an external power source to operate.  The copper pairs that are used to transmit the voice single also carry the voltage to power the communication.  Unlike VoIP, POTS lines will continue to operate during power outages.  Telephone providers house the equipment that is required for POTs lines in local facilities called Central Offices (CO’s).  Each CO is equipped with Uninterruptable Power Supplies (UPS) systems that include battery racks that power the phone lines during outages.  COs that service highly populated metropolitan areas also have backup generators that can power the phone lines during extended power outages. 

While the quality of VoIP is no longer a widespread problem, there is still the concern that VoIP relies on network connections.  If there are network performance issues, the result can be evident during VoIP communications creating quality issues such as resonance, delays, and background noise.  Performance issues can be addressed by ensuring that there is plenty of bandwidth available.  Rural areas and areas with limited internet bandwidth availability may not be able to implement VoIP without experiencing quality issues.

Sip Trunking

SIP trunking breaks down the voice or data into digital packets and sends them across the network (known as packet switching).  I have had the opportunity to manage the implementation of SIP trunking at large organizations and have seen the importance of proper configuration and quality of service (QoS).  QoS is a set of technologies that work on a network to guarantee its ability to dependably run high-priority applications and traffic under limited network capacity (What is QoS, n.d.). Tier 1 QoS is required for SIP trunking because this protocol is susceptible to throughput, jitter, latency, and errors.  VoIP, video conferencing, and other communications applications that are provided over SIP are very sensitive to the effects of network quality and require Tier 1 QoS.  The user experience of other applications such as web browsing and email is not impacted as much by QoS and can work at lower QoS tiers.

Session Initialization Protocol (SIP) trunks provide a widely acceptable and standardized method to get at least basic connectivity between a wide range of different call control solutions, including both voice and video (Hattingh, et al., 2010).  SIP is a commonly-used protocol for VoIP, video conferencing, and other communications services and replaces traditional phone lines and PBX systems.

I have encountered one issue that SIP trunking does not handle well.  The transmission and receiving of faxes are problematic for SIP. Particular codec (compression) settings are implemented with the intent that they can handle fax calls.  In reality, fax calls are not reliable over SIP.  If an organization needs to send and receive faxes (some still do today), a POTs line should be implemented.


Local, local toll, and long distance calling. (n.d.) FCC. Retrieved October 31, 2021 from  https://www.fcc.gov/consumers/guides/local-local-toll-and-long-distance-calling

Hattingh, C., Sladden, D.,Swapan, Z. (2010) SIP trunking Cisco Press.

What is quality of service?. (n.d) Paloalto Networks. Retrieved October 31, 2021 from https://www.paloaltonetworks.com/cyberpedia/what-is-quality-of-service-qos