VoIP Compatible High Speed Internet

Voice over IP (VoIP) technology is attracting more and more business users all the time. There are big advantages over traditional Plain Old Telephone Service (POTS) in features and cost savings. The big issue is what to do with the outside phone lines.

Why is this even a question? It’s because the century old public telephone system has been based on analog transmissions over twisted pair copper wiring. Many smaller companies still have multiple analog business lines connected directly to their phones or to Key Telephone systems or in-house PBX systems. Others who are big enough to need at least a half-dozen outside lines have moved to digital transmission via ISDN PRI, also called T1 PRI.

So, if PRI is digital then what’s the issue with VoIP?

Well, there’s digital and there’s digital. PRI telephone trunks are actually digital replications of the old analog lines. Each PRI consists of 23 channels that each carry one digitized phone conversation. One other channel is used for switching and data, like Caller ID. Those 23 PRI “B” channels are strung together end to end for transmission. Each channel is 8 bits wide and sampled 8,000 times a second. At the far end, the channels are separated and converted back to analog phone signals.

Note that nowhere here is any mention of packets. You know that computer networks all communicate using standardized packets of information. Each packet has both address and data bits. This allows switches and routers to get them from wherever they originate to wherever they are intended.

TDM (Time Division Multiplexed) lines, such as PRI, use channels instead of packets. The switching function is provided by the central office switch. When a phone call is in process, there is a direct electrical connection between the two callers. That connection is set up at the beginning of the call and torn down when the call is over.

If you are thinking that PRI service isn’t really compatible with VoIP, you’d be partially right. It’s really a conversion process between your office phone system that might be VoIP and the Public Switched Telephone Network (PSTN) that is still analog and TDM based. What VoIP really needs is a telephone line that is compatible with packet switched technology.

The first obvious option is to use the Internet to connect you with your VoIP phone service provider. After all, the Internet is readily available, relatively inexpensive to access, and packet based. Remember that Internet Protocol (IP) is the basis of VoIP.

What gets missed is that there is a big difference in the technology that includes Internet Protocol and the actual performance of the public Internet itself. One issue is that the Internet is open to anyone to do pretty much anything they want on it. There is no traffic manager ensuring that each user gets adequate resources for their particular application. There is a pool of resources and it’s first packet come, first served. Your voice packets may be competing with users backing up their files to the cloud, accessing ecommerce websites or downloading HD videos. If there is enough low latency bandwidth for everyone, then no problem. If the pipes get clogged up like rush hour on the Interstate, then you get what you get.

That can be a big problem for sensitive packet streams such as VoIP calls. Network congestion can cause dropped packets that distort the voice, delay some packets so they arrive out of sequence and are discarded, or impose a noticeable delay that makes two-way conversations difficult.

You can improve your chances of getting decent VoIP voice quality by using dedicated instead of shared bandwidth for your connection. That means Ethernet over Copper or T1 lines instead of cable broadband or DSL. You can also impose QoS (Quality of Service) through your own router so that at least your VoIP conversations aren’t competing with computer file transfers in your own office.

A better idea, although a bit pricier, is to use a dedicated private line called a SIP trunk between your network and your service provider. QoS is maintained by the service provider from end to end. As long as you have enough bandwidth to support all the calls you want to make, everything should work beautifully all the time. SIP trunks can be set up to provide you with both telephone service and broadband Internet access. This is done by dividing up the trunk so that phone calls and Internet are kept completely separate.

Are you considering a change to your business phone system because you are dissatisfied with how it works or are looking to add features or reduce costs? Investigate enterprise VoIP and hosted PBX solutions with SIP Trunks as a better approach for your company.

IP T1 Line Service

T1 line service has been available for decades. It originated as a proprietary telephone company technology designed as a trunk for transporting multiple phone calls between switching centers. Later, T1 was made available for businesses to support their PBX phone systems. When the Internet came along, T1 lines were pressed into service as dedicated Internet connections. But now we live in an IP world. Can T1 also act as an IP connection?

Yes, it can. That may seem counterintuitive to those who understand the origins and technology behind T1 service. The T-Carrier specifications, of which T1 is the most popular line service, describe a system organized as multiplexed channels 64 Kbps wide. That channel size was optimized to transport a single independent digitized telephone call using PCM (Pulse Code Modulation). Clearly, T1 is oriented toward the switched circuit based public telephone network.

That’s true, but the important thing to remember about digital network technologies is that a bit is a bit. It’s either true or false, one or zero, regardless of the particular physical layer or higher level protocols involved. That means that a time division multiplexing technology like T1 can be used to transport a packet oriented technology like IP or Ethernet with a little protocol conversion.

That’s essentially what’s being done when T1 lines are used for data transmission. It’s been a long time since anything but Ethernet has been the standard for local area networks. Ethernet is an IP technology, based on packet switching. Those packets can be queued up and loaded into T1 frames for transmission through T1 lines and even multiplexed into T3 and SONET frames for longer haul transmission. At the far end, the packets are offloaded and sent on their way through an IP edge router connected to the T1 CPE (Customer Premises Equipment.)

If you want to connect your Ethernet networks over metropolitan and wide area networks, one technology you’ll be interested in is called Ethernet over T1 or EoT1. This is also called EoDS1 for Ethernet over DS1.

DS1 is simply the data service or protocol that runs on T1 lines. The reason there are two designations is that T1 describes a physical line consisting of two twisted pair copper telco loops running at 1.5 Mbps. The DS1 is all the bits formated for transmission just before loading into the actual T1 line. You can take that same DS1 and feed it into an add/drop multiplexer and transport it along with many others on a T3 circuit or a fiber optic service like OC-3. At the other end, the DS1 can be demultiplexed from the other services on the same line and delivered separately.

In practice T1 and DS1 refer to the same thing to the actual user. What’s important is that Carrier Ethernet service can be delivered on a T1 line, albeit bandwidth limited to 1.5 Mbps. Who would want service that slow? Lots of companies need connectivity between locations, but don’t require high speeds. They may be using the service for retail credit card verification, communication with corporate headquarters, or to upload files to their web server. The big advantage they have with T1 lines is that they are almost universally available. If you can get business phone service, chances are that you can also get a T1 line installed. They are connected over the same telco wiring.

The competing service to Ethernet over T1 is Ethernet over Copper. That may seem like a fine line of distinction, but it is important. Ethernet over Copper (EoC) also uses twisted pair copper but a different modulation scheme that offers higher bandwidths but with distance limitations. If you are within a mile or two of the central office that has Ethernet over Copper equipment, you may be able to get 10 Mbps, 20 Mbps or even higher bandwidths from EoC. Some installations are transporting in excess of 100 Mbps over multiple copper pair.

Ethernet over T1 bandwidth can also be improved by adding more copper pair. The process of combining the bandwidths of several T1 lines into one larger bandwidth is called bonding. EoT1 bonding can deliver up to 10 or 12 Mbps to both metropolitan and rural areas, providing the equipment is available.

Are you interested in an IP connection for your computer or converged voice and data networks? If so, get pricing and availability for Ethernet over T1 or Copper now to see how much bandwidth is available for your business locations.

AboveNet Leads in High Bandwidth Ethernet Connectivity

There's a major transition underway in high bandwidth telecom services. It's a move from traditional SONET / SDH technology to Ethernet IP technology. There are good reasons for this evolutionary, or should I say revolutionary, change. They are rooted in the decades-long transition from analog to digital communications and the near universality of Ethernet as the network protocol of choice. Could we be at a tipping point for Ethernet in fiber optic communications? AboveNet makes a good case for just that.

AboveNet is a high bandwidth provider serving fifteen major U.S. markets plus the United Kingdom. They specialize in fiber optic MAN and WAN connectivity from 100 Mbps to 10 Gbps for companies that need this kind of bandwidth at lower costs than traditional telco solutions.

In their white paper, "Advantages of Ethernet vs Sonet, A Compelling Choice," AboveNet makes the case that cost is a major driver but not the only reason to switch from SONET / SDH to Gigabit Ethernet (Gig E). Ethernet is a better match with today's networks that are increasingly IP based. SONET is a TDM technology based on channels rather than packets. It works as a metro and long haul carrier for packet based networks, but with an inefficiency caused by the protocol conversions back and forth from TDM to IP. This can result in added latency and increased risk for data loss, as well as higher costs.

What may be lost to history is that SONET, the Synchronous Optical NETwork, is a product of telephone company research. At its foundation is the 64 Kbps data channel or DS0. There are thousands of them all multiplexed and synchronized to create SONET fiber optic high bandwidth services. Why such an arrangement? Each of those small channels is just the right size to carry one digitized telephone call. That was the original impetus for SONET. It was to efficiently transport high volumes of telephone calls from one telephone exchange to another.

SONET, of course, has grown from it's switched circuit telephony roots. With appropriate protocol conversions, those DS0 channels can be aggregated to transport IP packets as well as PCM (Pulse Code Modulation) voice. SONET has been the dominant technology for long-haul networks and fiber optic MAN and WAN connections. It's design includes redundant paths with a 50 mSec failover time to make it a highly reliable transport service.

But telephony as well as everything else in electronic communications is going to IP or Internet Protocol. VoIP is replacing analog and TDM telephony for business and residential users. At the enterprise level, there are enormous cost savings possible with converged voice/data/video networks. Why create an all-IP network based on Ethernet within the enterprise, only to have to convert it to TDM-based SONET for transport between locations or to a distant IP service provider?

Carrier Ethernet, the flavor of Ethernet specified for metropolitan and long haul networks, has the advantage of being IP at its core. No conversions are necessary from LAN to MAN to WAN and back to LAN at some remote location. This seamless connectivity reduces latency and improves network efficiency by eliminating conversion steps.

AboveNet operates its own network with over 2 million fiber miles worldwide and a reach of more than 1,800 lit buildings. Their services included MAN and WAN connectivity, plus managed services for WDM Wavelength, Metro Ethernet, WAN Ethernet and IP transit.

If your organization has a need for high bandwidth services and you want to acquire them at the best possible price, then consider getting competitive quotes on fiber optic services from AboveNet and other highly competitive carriers. This telecom brokerage service is free to serious business users, with complementary consulting on your corporate requirements.