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Telecom Solutions 101: Voice & Data Circuit Basics

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Every company, regardless of size, needs connectivity to the “outside world” for voice and data.  Small offices typically use simple analog lines and DSL or cable Internet for cost effective connections. Larger offices need higher capacity for voice connectivity and higher bandwidth for data applications such as Voice over IP (VoIP), video or other data applications. Let’s review the options, how they scale and the benefits of the different solutions.

Voice Connections

The basic voice connection is a simple analog line, commonly referred to as plain old telephone service (POTS) line. Virtually all phone systems accommodate these circuits and companies who use them run local and long distance service over them. Local phone companies still offer features such as call forward, roll over, caller ID and call waiting for a fee. Other businesses may still use a service called CENTREX lines, which used to be popular when phone systems were too costly for smaller companies.

At some point, as a company grows — possibly when you get to 8 or 10 analog lines — it may be more cost-effective to upgrade from analog service to digital service. Most growing companies will migrate to a PRI (Primary Rate Interface), which is a digital circuit that provides 23 digital trunks for inbound and outbound calling. A similar service is a DS-1 or T-1 line, which provides 24 digital channels. 

PRIs and T-1s are used for companies that do a higher volume of calling. This is because PRIs and T-1s offer more trunks (lines) for less cost as well as lower long distance rates.

One thing to be aware of with PRIs is whether the service is “measured” or “non-measured.” “Measured” means that there is a limit on the number of local calls that can be made without a per-minute fee, while “non-measured” means that all local calling is included in the monthly fixed cost. In either case, long distance calls are billed on a per-minute basis.

When comparing PRI costs, remember that a lower cost might mean it is a measured circuit and you will end up paying for local calls. In most cases, a non-measured circuit is preferable because for a slightly higher monthly fee you do not have to worry about how many local calls you are making.

Voice circuits can grow from PRI or DS-1 to larger voice circuits such as DS-3 or OC-3 that high-end call centers or very large companies use. 

Data Connections

Data is where the largest growth and changes have been made in recent years. Carriers have upgraded their networks to deliver high-speed data at very competitive costs.

When we refer to data, we are typically referring to the connections to the public Internet or a private network connection between offices and/or cities. This becomes important when companies want to run voice and video over their networks. The circuits must have the bandwidth to handle the traffic and more importantly, they must have QOS (quality of service) or COS (class of service) to allow the prioritization of video and voice traffic over simple data traffic such as Internet browsing or email. This makes for a much clearer connection and is imperative for eliminating jitter or latency on voice and video transmissions.

Simple Internet access comes in many flavors. On the low end you have “shared services” such as DSL or cable modems. These are low-cost solutions that can be very effective for small offices.  

Beyond those services we move into the traditional Internet circuits. These can be T-1 (1.5 Mbps) or multiples of T-1s (3.0 Mbps, 4.5 Mbps, etc.), and can reach up to and beyond DS-3 (45 Mbps) speeds, but typically require that you terminate the circuits with your own equipment such as routers.

Better yet are Ethernet solutions which do not require client hardware (routers) and are delivered as an Ethernet hand-off. These are very scalable and flexible and usually start at 10 Mbps and go up from there, most commonly up to 100 Mbps. 

Are you confused yet?

Sometimes it is confusing when you compare the low-cost cable Internet service you may have at home that is 10 Mbps to a commercial T-1 that is only 1.5 Mbps, and you may wonder why there is such a difference in cost for a seemingly lower speed circuit? The main reason is due to the fact that in most cases, DSL and Cable solutions are shared services, meaning that many other customers share your connection, and may use the same access that you have at different times, therefore you have the potential to experience disparate performance. (Have you ever noticed at home that sometimes your Internet is really fast and other times it’s slow? Well, that’s why!) 

For business circuits, the access is not shared and is instead totally dedicated to that one customer so the speed is fixed and symmetrical (same speed up and down). The up and down speeds on shared services are typically different, i.e. 3 up – 10 down. This is most prevalent in DSL, for example, ADSL or Asynchronous DSL (speeds up and down are different) verses SDSL or Synchronous DSL (speeds up and down are the same). SDSL is sometimes called Commercial Grade DSL.

Wireless data connections are also becoming popular and carriers such as Lightyear, Verizon and Sprint have offerings that are cost effective and have decent bandwidth.

WAN (Wide Area Network) Connections

Companies that have multiple locations need connectivity. Often, the connections must be compliant with industry regulations relating to security (healthcare, financial, and so on). The simple way to do the connections is through Virtual Private Network (VPN) connections over the public Internet. As long as the site has an Internet connection, a secure VPN can be established using firewalls or other similar hardware. This is the most economical solution for WANs, however it has its drawbacks.

VPN Firewall

As mentioned earlier, the challenge with VPNs over the public Internet is that there is no QOS or COS, so all packets travel at the same priority. Voice or video do not have priority over any other data, often causing quality problems. For this reason, VPNs are not a solid solution for any site that has more than a few employees or where the demands for voice and video are high.

Options beyond this are to install either point-to-point private networks or MPLS (Multiple Protocol Label Switching). A point-to-point circuit is a good solution if there are only two sites and no growth is expected.  However, if there are more than two sites or plans to expand, MPLS is the absolute best solution.

MPLS circuits take any type of traffic (Multiple Protocol) and prioritize the way different packets (data, voice, or video) are transmitted over the circuit. This is done by tagging each packet with what type of packet it is (Label Switching). For example, if two packets hit the circuit at the same time and want to travel from point A to point B and one packet is voice while the other is data, the MPLS circuit will give priority to the voice packet. This means that you have QOS or COS with MPLS and the voice or video quality is now assured.

The other major advantage is that MPLS allows for fully meshed connectivity for multiple sites. This makes for much easier designs relating to disaster recovery solutions and back-ups.  MPLS is a private IP connection and meets all requirements for industry compliance and security and can be run through regular or multiple T-1s or Ethernet.

There are options to get Internet access off of the MPLS connections if you desire, via cloud computing solutions. This means you can share your one connection for multiple accesses and may be a better way to deliver Internet across your enterprise. Alternatively, all remote sites could “home run” back to the headquarters over the private MPLS and hop on a single Internet circuit at that point. Which option is best depends on the design philosophy within your organization.

Hybrid Circuits

Finally, we need to briefly touch on the converged circuits that most carriers offer. They can be called different names such as “Converged Circuit,” “Flex Circuit” or “Dynamic Circuit” but they all do basically the same thing — through one connection (1.5 Mbps, 3.0 Mbps, 10 Mbps whatever), they deliver multiple services such as:

• Local calling
• Long distance calling
• Internet access
• WAN connectivity options (ability to connect to other converged circuits in your enterprise)

Bundling the services provides some benefits such as:

• Overall costs are typically lower
• Single point of contact for everything
• One bill to pay

Additionally, depending on the carrier they may offer a bundle of long distance minutes along with the service or greatly reduced calling rates. 

These circuits are very viable solutions for small-to-medium sized businesses. One drawback is the fact that if your one connection goes down you lose local calling, long distance calling and Internet access. Therefore, some companies will install one or two analog lines outside or their converged circuit to have a safety net back up capability in the event of that circuit failing.

Summary

This discussion was intended as an overview. My hope is that for those learning about their voice and data options as their company grows, it provided a better understanding of some of the options available today.

Subscribe to the MCPc blog to stay up-to-date as we dive deeper into the subject of voice and data solutions, as well as other technology solutions important to today’s growing business.

Frank Marro served as Regional Vice President responsible for sales management in Cincinnati, Dayton and Columbus, Ohio. He also directed MCPc’s national carrier service program, which provides solutions for clients looking for voice, video and data circuits for WAN connectivity.

Image Credits:

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