jump to navigation

Boxborough’s Lightower Fiber Networks, a fiber network provider, acquires NYC’s Lexent Metro Connect October 3, 2010

Posted by HubTechInsider in Acquisitions, Fiber Optics, Startups.
Tags: , , , , , , , , ,
add a comment
Image representing Lightower Fiber Networks as...

Image via CrunchBase

Boxborough’s Lightower Fiber Networks, a fiber network provider, acquires NYC’s Lexent Metro Connect, a provider of dark fiber networks, for undisclosed terms. Lightower Fiber Networks is headquartered in the same old former DEC building that houses eSpendwise, the employer of the Hub Tech Insider.

Related Articles

Verizon to open new Waltham, Massachusetts 4G & FiOS Innovation & Research Center April 19, 2010

Posted by HubTechInsider in events, Fiber Optics, Mobile Software Applications, Telecommunications, Wireless Applications.
Tags: , , , , , ,
1 comment so far

Verizon Communications Inc. says it plans to start building a new research center in Waltham, Massachusetts focused around 4G wireless Long Term Evolution (LTE) technology. Verizon Wireless currently is piloting an LTE network deployment in parts of Boston. The new Verizon Waltham Technology Innovation Center will eventually house more than 300 scientists and researchers, officials said, most of whom are already working for Verizon in two exisitng buildings at that location.


In addition to its LTE research, the new Waltham campus will house researchers working on other Verizon offerings. LTE is the major focus of that building, but there will also be other Verizon work going on, including the further development of FiOS.


The campus at 117 West St. in Waltham will include three buildings once the new one is finished. In addition to the research space, it will house offices, as well as an executive briefing center.


As of August 2009, Verizon had 10 LTE 4G cell sites running around Greater Boston in its pilot deployment. LTE wireless service is expected to provide up to 10 times the speed – or about 8 megabits per second – of current 3G services. In March, Verizon announced that in its pilot deployments it was seeing average speeds of between 5Mbps and 12Mbps on a download in real world use, with peaks as high as 50Mbps.


Andover’s Polatis, a developer of optical switching technology, raises $1.2 Million from a group of undisclosed investors February 5, 2010

Posted by HubTechInsider in Fiber Optics, Startups, Venture Capital.
Tags: , , ,
add a comment

Andover’s Polatis, a developer of optical switching technology, raises $1.2 Million from a group of undisclosed investors.


Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

Get ready for high definition cellular and landline telephone calls November 3, 2009

Posted by HubTechInsider in Fiber Optics, Telecommunications, VUI Voice User Interface.
Tags: , , , , , , , , ,
add a comment
Uganda - mobile phone charging service

Image via Wikipedia

For over forty years, the quality of telephone calls has changed very little. The shift in the 1990’s from analog to digital cellular technology promised crisper quality, but the results never panned out. Struggling with 30% annual increases in cellular traffic, cellular telephone companies used the improved technology to add capacity, not improved quality.

Today the demand for cellular minutes is nearing its zenith, with mature growth levels of only 3% in the past year. Now the relentless advance of digital technology advances in cellular communications can be used for purposes other than simply packing more telephone calls into the cellular airwaves.

To this point in time, the big U.S. carriers plan to use their growing capability to provide all sorts of data services, but eventually, the cost of better sounding voice calls will be too cheap to ignore. Today’s carriers convert telephone calls into 6,000 digital bits per second, a tight squeeze and the major reason telephone calls sound so poor today. In the tiny European country of Moldova, French wireless carrier Orange has now deployed the world’s first high definition cellular telephone network, which uses double the number of bits per second. The highs and lows of the human voice are not so badly mangled using the high definition cellular telephone system.

In the U.S., chipmaker Broadcom is working on new equipment that will allow even better-sounding telephone calls. 32,000 digital bits per second will produce voice quality that is virtually indistinguishable from face-to-face conversation. The technology portends a clear audible improvement over not just ordinary cellular telephones but also landline telephones, which chop off high frequencies, especially above 3 kHz, the frequency range in which much human speech falls into.

Another big problem with cellular telephone calls is the annoying apparent lag that occurs between the moment when one caller speaks and the time his voice reaches the other person’s ear. Many people assume that’s an inherent drawback of cellular telephones, but it is not. Wireless digital cellular signals fly through the air at the speed of light just as they do in optical fiber – the delays come from slow software and circuitous routing. The new Long Term Evolution (LTE) gear set for deployment next year should cut that lag by at least 75%, so much that most human ears won’t notice it anymore.

Landline telephones stand to gain from the same quality advances as well. Orange has already installed 500,000 high definition landline telephones in Europe that use voice over internet technology (VOIP). When this style of telephone connection first hit the scene, it was roundly criticized for its poor sound quality relative to traditional landline telephones, but Orange and other carriers, some of whom are in the U.S. like Vonage, have shown that better technology can close that quality gap and then some. Both cellular telephone and Internet landline telephone calls may soon sound terrific as a result.

What is Cao’s Law? June 11, 2009

Posted by HubTechInsider in Definitions, Fiber Optics, Telecommunications.
Tags: , ,
add a comment

Cao’s Law states that the communications spectrum is virtually infinite and that WDM (Wave Division Multiplexing) will allow the information transmitted upon the available spectrum to expand exponentially as the growth of transistors in Moore’s Law. Using less and less power, WDM will allow finer and finer channels of light to transmit more and more data. Cao’s Law states that these lambdas will expand at a rate two to three times the rate of expansion of transistors on an integrated circuit chip as in Moore’s Law. On optical fibers, as opposed to the tradeoffs between power and connectivity in the transistor world, in the optical realm, the tradeoff is between bitrate and channel count. To this point of the technology’s development, we can either pump a high bitrate on each channel or we can transmit lots of channels, but we cannot do both of these things at the same time. Among telecom carriers today, there seems to be a manifestation of Simon Cao’s Law in action in the real world.

SS7 – Signaling System Seven – Telecommunications Protocol SS7 June 10, 2009

Posted by HubTechInsider in Fiber Optics, Telecommunications.
Tags: , , , , , , , ,
1 comment so far
SS7 software layers

SS7 software layers

In Signaling System 7 (SS7) protocol, a worldwide standard (with variations), routing intelligence is located in low cost computer-based equipment rather than in central office switches.

One of the primary benefits of SS7 is global interoperability. It has the capability to enable all carriers to cooperate with each other. It is a standard protocol approved by the ITU. Global billing, toll-free calling, 900-number services, and international wireless call roaming are all call features that are dependent on SS7.

SS7 is used on a global basis. In North America, the ANSI version of SS7 is used. In Europe, the ETSI version is used. In other pats of the world, the ITU version of SS7 is used.

Gateways allow these international SS7 implementations to communicate with each other.

SS7 is essential to modern networking. With SS7, an overlaid packet switched network controls the underlying voice network’s operation and signaling information is carried on a separate channel from voice and data traffic.

Because signaling is such a quick network activity, it is possible to multiplex many signaling messages over one signaling channel using a packet switching arrangement.

SS7 permits the telephone company to provide one database for several switches in order to freeup switch capability for other functions. This is the capability that makes SS7 the foundation for Intelligent Networks (INs) as well as Advanced Intelligent Networks (AINs).

As an example, in order to provide a service such as 900 number and toll-free calling, in SS7, powerful parallel processing computer systems hold massive databases with information such as routing instructions for toll-free and 900 number telephone calls. One processor with its database supports many central office switches under SS7. in this way, each central office itself is not required to host the centralized database. Without the need to share the expense of maintaining the sophisticated routing information, each central office can share in the expense of a database or feature upgrade to the centralized SS7 datastore.

MCI first implemented SS7 into its network in 1988. SS7 enabled them to halve their call setup time on calls between Philadelphia and Los Angeles. Freeing up voice channels from their previous signaling duties pre-SS7 enabled carriers to pack more voice calls on their existing network paths.

Cellular networks use SS7 technology to support roaming. Every cellular provider has a database called the home location register, or HLR, where complete information regarding each subscriber is kept. They also maintain a database called the VLR, or visitor location register, that maintains information on each caller who visits from other areas. When a cellular subscriber roams, each network they visit exchanges SS7 messages with their “home” network. The subscriber’s home system also marks its HLR so that it knows where to send calls for its customers who are roaming.

SS7 has three major components:

1. Packet switches – Signal Transfer Points that route signals between databases and central switches. STPs, or Signal Transfer Points, are responsible for translating the SS7 messages and then routing these messages amongst the various network nodes and databases. Signal Transfer points are packet switches that route signals between central offices as specialized databases. Messages are sent between points on the SS7 network in variable-length packets with the addresses attached. Signal transfer switches read only the address portion of the packets and forward the messages accordingly.

2. Service Switching Points – Software and ports in central offices that enable switches to query databases. SSPs are the switches that begin and end calls. They receive signals from the Customer Provided Equipment (CPE) and then process the calls on the behalf of the end users. The user triggers the network to provide various services by dialing particular digits. SSPs are typically implemented at access tandem offices, local exchanges or toll centers that contain the needed network signaling protocols. The SSP serves as the begining and ending point for SS7 messaging.

3. Service Control Points – DBs with customer feature and billing information. Service Control Points, or SCPs, interface with SSPs as well as STPs. The STP contains the network configuration and call-completion database – the SCP contains all the service logic that is needed to deliver the type of call and feature in the call that the user is requesting. SCPs are centralized network nodes that contain software and databases needed for call management. Functions such as digit translation, call routing and verification of credit cards are all provided by SCPs. Usually a SCP will receive traffic from a SSP via the STP and will then return responses based on those queries by way of the STP.

The SS7 signaling data link is a full duplex digital transmission channel that operates at either 56 Kbs (T-Carrier transmission systems, in North America) or 64 Kbps (E_Carrier transmission systems, Europe). SS7 also defines a number of other types of links, each with a specific use within a SS7 network.

A (access) links
B (bridge) links, D (diagonal) links, and B/D links
C (cross) links
E (extended) links
F (fully associated) links

Geek T-Shirts, Decals, and more at http://www.tshirtnow.net

Want to know more?

You’re reading Boston’s Hub Tech Insider, a blog stuffed with years of articles about Boston technology startups and venture capital-backed companies, software development, Agile project management, managing software teams, designing web-based business applications, running successful software development projects, ecommerce and telecommunications.

About the author.

I’m Paul Seibert, Editor of Boston’s Hub Tech Insider, a Boston focused technology blog. I have been working in the software engineering and ecommerce industries for over fifteen years. My interests include computers, electronics, robotics and programmable microcontrollers, and I am an avid outdoorsman and guitar player. You can connect with me on LinkedIn, follow me on Twitter, follow me on Quora, even friend me on Facebook if you’re cool. I own and am trying to sell a dual-zoned, residential & commercial Office Building in Natick, MA. I have a background in entrepreneurship, ecommerce, telecommunications and software development, I’m a Technical PMO Director, I’m a serial entrepreneur and the co-founder of several ecommerce and web-based software startups, the latest of which are Twitterminers.com and Tshirtnow.net.

More Articles From Boston’s Hub Tech Insider:

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

Related articles

What is an ACNA? What is a CCNA code in telecommunications? June 8, 2009

Posted by HubTechInsider in Definitions, Fiber Optics, Telecommunications, Uncategorized.
Tags: , , , ,
add a comment

An ACNA stands for Access Customer Name Abbreviation; It is a three-digit alpha code assigned to identify carriers, both ILECs (Incumbent Local Exchange Carriers) and CLECs (Competitive Local Exchange Carriers), for billing and other identification purposes.

It is closely related to the CCNA code, or the Customer Carrier Name Abbreviation, which identifies the common language code for the IXC (InterExchange Carrier) providing the interLATA facility.

The CCNA reflects the code to be contacted for provisioning whereas the ACNA reflects the IXC to be billed for the service.

Geek T-Shirts, Decals, and more at http://www.tshirtnow.net

Want to know more?

You’re reading Boston’s Hub Tech Insider, a blog stuffed with years of articles about Boston technology startups and venture capital-backed companies, software development, Agile project management, managing software teams, designing web-based business applications, running successful software development projects, ecommerce and telecommunications.

About the author.

I’m Paul Seibert, Editor of Boston’s Hub Tech Insider, a Boston focused technology blog. You can connect with me on LinkedIn, follow me on Twitter, even friend me on Facebook if you’re cool. I own and am trying to sell a dual-zoned, residential & commercial Office Building in Natick, MA. I have a background in entrepreneurship, ecommerce, telecommunications and software development, I’m the Senior Technical Project Manager at eSpendWise, I’m a serial entrepreneur and the co-founder of Tshirtnow.net.

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

More Articles From Boston’s Hub Tech Insider:

The Advantages and Disadvantages of Fiber Optics June 4, 2009

Posted by HubTechInsider in Fiber Optics, Telecommunications.
Tags: , , , , , , ,
10 comments
English: A TOSLINK fiber optic cable with a cl...

English: A TOSLINK fiber optic cable with a clear jacket that has a laser being shone onto one end of the cable. The laser is being shone into the left connector; the light coming out the right connector is from the same laser. (Photo credit: Wikipedia)

Advantages of fiber optics:

1. Extremely high bandwidth – No other cable-based data transmission medium offers the bandwidth that fiber does.

2. Easy to accomodate increasing bandwidth – Using many of the recent generations of fiber optic cabling, new equipment can be added to the inert fiber cable that can provide vastly expanded capacity over the originally laid fiber. DWDM, or Dense Wavelength Division Multiplexing, lends fiber optic cabling the ability to turn various wavelengths of light traveling down the fiber on and off at will. These two characteristics of fiber cable enable dynamic network bandwidth provisioning to provide for data traffic spikes and lulls.

3. Resistance to electromagnetic interference – Fiber has a very low rate of bit error (10 EXP-13), as a result of fiber being so resistant to electromagnetic interference. Fiber-optic transmission are virtually noise free.

4. Early detection of cable damage and secure transmissions – Fiber provides an extremely secure transmission medium, as there is no way to detect the data being transmitted by “listening in” to the electromagnetic energy “leaking” through the cable, as is possible with traditional, electron-based transmissions. By constantly monitoring an optical network and by carefully measuring the time it takes light to reflect down the fiber, splices in the cable can be easily detected.

Disadvantages of Fiber Optics:

1. Installation costs, while dropping, are still high – Despite the fact that fiber installation costs are dropping by as much as 60% a year, installing fiber optic cabling is still relatively costly. As installation costs decrease, fiber is expanding beyond its original realm and major application in the carrier backbone and is moving into the local loop, and through technologies such as FTTx (Fiber To The Home, Premises, etc,) and PONs (Passive Optical networks), enabling subscriber and end user broadband access.

2. Special test equipment is often required – The test equipment typically and traditionally used for conventional electron-based networking is of no use in a fiber optic network. Equipment such as an OTDR (Optical Time Domain Reflectometer)

is required, and expensive, specialized optical test equipment such as optical probes are needed at most fiber endpoints and connection nexuses in order to properly provide testing of optical fiber.

3. Susceptibility to physical damage – Fiber is a small and compact cable, and it is highly susceptible to becoming cut or damaged during installation or construction activities. Because railroads often provide rights-of-way for fiber optic installation, railroad car derailments pose a significant cable damage threat, and these events can disrupt service to large groups of people, as fiber optic cables can provide tremendous data transmission capabilities. Because of this, when fiber optic cabling is chosen as the transmission medium, it is necessary to address restoration, backup and survivability.

4. Wildlife damage to fiber optic cables – Many birds, for example, find the Kevlar reinforcing material of fiber cable jackets particularly appealing as nesting material, so they peck at the fiber cable jackets to utilize bits of that material. Beavers and other rodents use exposed fiber cable to sharpen their teeth and insects such as ants desire the plastic shielding in their diet, so they can often be found nibbling at the fiber optic cabling. Sharks have also been known to damage fiber optic cabling by chomping on it when laid underwater, especially at the repeating points. There is a plant called the Christmas tree plant that treats fiber optic cable as a tree root and wraps itself around the cable so tightly that the light impulses traveling down the fiber are choked off.

HubTechInsider.com YouTube Channel

Subscribe to HubTechInsider.com YouTube Channel

SEO Made Easy 2013 FREE Special Report!

PHP for Beginners

Google + Domination for Business

LinkedIn for Business Training Course

Mastering WordPress Video Training Course

Twitter Business Magic Video Tutorial Series

Want to know more?

You’re reading Boston’s Hub Tech Insider, a blog stuffed with years of articles about Boston technology startups and venture capital-backed companies, software development, Agile project management, managing software teams, designing web-based business applications, running successful software development projects, ecommerce and telecommunications.

About the author.

I’m Paul Seibert, Editor of Boston’s Hub Tech Insider, a Boston focused technology blog. You can connect with me on LinkedIn, follow me on Twitter, even friend me on Facebook if you’re cool. I own and am trying to sell a dual-zoned, residential & commercial Office Building in Natick, MA. I have a background in entrepreneurship, ecommerce, telecommunications and software development, I’m the Senior Technical Project Manager at Cartera Commerce, I’m a serial entrepreneur and the co-founder of Tshirtnow.net.

Eight ways to tell if your Project Team is on the Way Up, or on the Way Down

What is ‘Management By Walking Around’?

What is Scrum?

What is a “Use Case”?

What is a “User Story”?

The Twenty Laws of Testing Computer Software

Add to Google Buzz

Like This!

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

Related Articles
More Articles From Boston’s Hub Tech Insider:

An explanation of the Nyquist Theorem and its importance to Mu-Law Encoding in North American T-Carrier Telecommunications Systems June 2, 2009

Posted by HubTechInsider in Definitions, Fiber Optics, Mobile Software Applications, Telecommunications, VUI Voice User Interface, Wireless Applications.
Tags: , , ,
add a comment

nyquist100

The Nyquist theorem established the principle of sampling continuous signals to convert them to digital signals. In communications theory, the Nyquist theorem is a formula stating that two samples per cycle is all that is needed to properly represent an analog signal digitally. The theorem simply states that the sampling rate must be double the highest frequency of the signal. So, for example, a 4KHz analog voice channel must be sampled 8000 times per second. The Nyquist Theorem is the mathematical underpinning of the Mu-Law encoding technique used in T-Carrier transmission systems. T-Carrier is used in North American telecommunications networks. In Europe, where E-carrier transmission systems are used, a similar but incompatible theorem, Shannon’s Law, is used in the European A-Law encoding technique. This is the reason why Mu-Law encoding is used in North America and A-Law encoding is used in Europe.

The author of the Nyquist Theorem was named Harry Nyquist. Harry worked in the research department at AT&T and later at Bell Telephone Laboratories. In 1924, he published a paper titled “Certain Factors Affecting Telegraph Speed”, which analyzed the correlation between the speed of the telegraph system and the number of signal values it used. Harry refined his paper in 1928, when he republished his work under the title “Certain Topics in Telegraph Transmission Theory”. It was in this paper that Harry expressed the Nyquist Theorem, which established the principle of using sampling to convert a continuous analog signal into a digital signal. Claude Shannon, the author of Shannon’s Law, cited both of Nyquist’s papers in the first paragraph of his classic paper “The Mathematical Theory of Communication”. Harry Nyquist is also known for his explanation of thermal noise, also sometimes known as “Nyquist noise” as well as AT&T’s 1924 version of a fax machine, called “telephotography”.

His remarkable career included advances in the improvement of long-distance telephone circuits, picture transmission systems, and television. Dr. Nyquist’s professional, technical, and scientific accomplishments are recognized worldwide. It has been claimed that Dr. Nyquist and Dr. Claude Shannon are responsible for virtually all the theoretical advances in modern telecommunications. He was credited with nearly 150 patents during his 37-year career. His accomplishments underscore the excellent preparation in engineering that he received at the University of North Dakota. In addition to Nyquist’s theoretical work, he was a prolific inventor and is credited with 138 patents relating to telecommunications.





Want to know more?

You’re reading Boston’s Hub Tech Insider, a blog stuffed with years of articles about Boston technology startups and venture capital-backed companies, software development, Agile project management, managing software teams, designing web-based business applications, running successful software development projects, ecommerce and telecommunications.


About the author.

I’m Paul Seibert, Editor of Boston’s Hub Tech Insider, a Boston focused technology blog. You can connect with me on LinkedIn, follow me on Twitter, even friend me on Facebook if you’re cool. I own and am trying to sell a dual-zoned, residential & commercial Office Building in Natick, MA. I have a background in entrepreneurship, ecommerce, telecommunications and software development, I’m the Senior Technical Project Manager at eSpendWise, I’m a serial entrepreneur and the co-founder of Tshirtnow.net.

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

What is the difference between Cellular and PCS? May 17, 2009

Posted by HubTechInsider in Definitions, Fiber Optics, Mobile Software Applications, Telecommunications, Uncategorized, VUI Voice User Interface, Wireless Applications.
Tags: , , ,
1 comment so far

Cellular is dual-classified as being inclusive of both analog and digital networks. Cellular networks began with analog infrastructures, and over time migrated this infrastructure to digital. In a cellular network, depending upon your location throughout the world, the operation frequencies are 800MHz to 900MHz band. Cellular infrastructure is generally based on a macrocell architecture. Macrocells involve a coverage area with a diameter of around 8 miles, and because of this large coverage area, cellular operates at high power levels, in a range of .6 to 3 watts.

PCS is a more recent technology, and has been all digital since inception. As with cellular, depending upon where you are located in the world, the frequency band of operation is in the 1.8GHz to 2GHz band. Instead of cellular macrocells, PCS uses two different infrastructures, both microcell and picocell. As these names imply, the coverage areas of these architectures are smaller than macrocells, around 1 mile in diameter. As a result, PCS uses much lower power levels – 100 milliwatts.

So the key differences between PCS and cellular are the frequencies in which they operate, coverage areas of their different cell architectures, and the power levels each uses to transmit signals. They work essentially the same way, use the same types of network elements, and perform the same functions.

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

The SONET and SDH Signal Hierarchy: How many T-1s are in an OC-1, OC-3, OC-12, or OC-48? May 10, 2009

Posted by HubTechInsider in Definitions, Fiber Optics, Telecommunications, Uncategorized.
Tags: , ,
add a comment

I have found that there exists out there in the wide world a touch of confusion when it comes to recognizing the different signal levels and transmission speeds associated with what is referred to in the telecom industry as digital hierarchies, the two most common of which are, in North America, the PDH and SDH, or SONET, hierarchies.

Throughout my work as a telecommunications enthusiast, a pastime of discovery which has kept me occupied ever since my teen years, and on through many of my professional pursuits, I have always served as a point of reference for others in regards to the various telecommunications signal levels as well as the transmission speeds that these levels in the hierarchies represent. The following is my rough attempt to put this information into one place that can serve as a reference for me and others:

SONET was developed to aggregate, or multiplex, circuit switched traffic such as T-1, (E-1 in Europe) T-3, and slower rates of data traffic from multiple sources on fiber-optic networks. SONET transports traffic at high speeds called OC (Optical Carrier). The international version of SONET is called the synchronous digital hierarchy (SDH). SDH carries traffic at synchronous transport mode speeds. Equipment interfaces make SONET and SDH speeds compatible with each other, so the same SONET switching equipment can be used for both OC and SDH speeds.

OC-1 operates at 52 Mbps and is equivalent to 28 DS-1s (same as a T-1) or 1 DS-3 (same as a T-3). OC-1 is generally used as customer access lines. Early-adopter types of customers such as universities, airports, financial institutions, large government agencies, and ISPs – use OC-1.

OC-3 operates at 155 Mbps and is equivalent to 84 DS-1s (same as a T-1) or 3 DS-3s (same as a T-3). OC-3 speeds are required by end users such as companies in the aerospace industry and high-tier ISPs.

OC-12 operates at 622 Mbps and is equivalent to 336 DS-1s (same as T-1) or 12 DS-3s. This is another capacity towards which high-tier ISPs are moving. It was originally deployed for the metropolitan area fiber rings built out across cities worldwide, although those rings are now moving to OC-48.

OC-48 operates at 2,488 Mbps and is equivalent to 1,344 DS-1s (same as a T-1) or 48 DS-3s (same as a T-3). This capacity has been deployed for backbone, or core, networks. Today the metropolitan area rings are moving from OC-48 to OC-192.

OC-192 operates at 9,953 Mbps and is equivalent to 5,376 DS-1s (same as a T-1) or 192 DS-3s (same as a T-3). OC-192 is in use for backbone networks.

OC-768 operates at 39,812 Mbps and is equivalent to 21,504 DS-1s (same as a T-1) or 768 DS-3s (same as a T-3). Use of OC-768 is very rare outside of testing or research networks due to the great expense of this transmission speed level.

At times, you may see OC levels such as OC-1c, OC-3c, OC-12c, etc. This is called concatenation, and it puts streams of data into one fat, or high-bandwidth, contiguous stream. For example, OC-1 speeds of 52 Mbps may be used to carry broadcast video. In this case, OC-1c, or concatenated OC-1, carries OC-1 streams back-to-back. These streams travel contiguously through the network as long as capacity is available. Most applications for concatenation are high-speed data and broadcast-quality video.

As far as the DS, or Digital Signal Levels, of the older PDH, or Plesiochronous Digital Hierarchy (plesiochronous means “minute variations in timing”), they follow what is known as the T-carrier signal levels. Technically, the DS-x and CEPT-x terminology (DS-1, DS-3, CEPT-1, CEPT-3, and so on) indicates a specific signal level (and thus usable bandwidth), as well as the electrical interface specification. T-x and E-x terminology (T-1, T-3, E-1, E-3, and so on) indicates the type of carrier – a specific implementation of a DS-x/CEPT-x. More often than not these days, however, the terms DS-x and T-x are used interchangeably. So some people might use the term DS-1 and T-1 to refer to the same thing – a digital transport that can carry 1.544 Mpbs over a total of 24 voice channels. In Europe, the same is true: E-1 is the same as CEPT-1, and so forth.

A DS-0 (T-0) has a bit rate of 64 Kbps and carries 1 voice-grade channel.

A DS-1 is equivalent to a T-1 and has a bit rate of 1.544 Mpbs and carries 24 voice channels.

A DS-2 has a bit rate of 6.312 Mpbs and carries 96 voice channels, equivalent to 4 T-1s. This is also sometimes referred to as a T-2, or T2.

A DS-3 has a bit rate of 44.736 Mpbs and carries 672 voice channels, equivalent to 28 T-1s. This is also sometimes referred to as a T-3, or T3.

A DS-4 has a bit rate of 274.176 Mpbs and carries 4,032 voice channels, equivalent to 168 T-1s. This is also sometimes referred to as a T-4, or T4.


Want to know more?

You’re reading Boston’s Hub Tech Insider, a blog stuffed with years of articles about Boston technology startups and venture capital-backed companies, software development, Agile project management, managing software teams, designing web-based business applications, running successful software development projects, ecommerce and telecommunications.


About the author.

I’m Paul Seibert, Editor of Boston’s Hub Tech Insider, a Boston focused technology blog. You can connect with me on LinkedIn, follow me on Twitter, even friend me on Facebook if you’re cool. I own and am trying to sell a dual-zoned, residential & commercial Office Building in Natick, MA. I have a background in entrepreneurship, ecommerce, telecommunications and software development, I’m the Senior Technical Project Manager at eSpendWise, I’m a serial entrepreneur and the co-founder of Tshirtnow.net.

Add to Google Buzz

Like This!

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

More Articles From Boston’s Hub Tech Insider:

An explanantion of telecommunications industry CLLI “Silly” Codes April 20, 2009

Posted by HubTechInsider in Definitions, Fiber Optics, Telecommunications, Uncategorized, Wireless Applications.
Tags: ,
1 comment so far

What the heck is a “Silly” Code? Allow me to explain…

A CLLI, (pronounced “Silly”) code is a telecommunications industry-standard and is an alphanumeric code of 11 characters, CLLI was developed by Bellcore (now telecordia Technologies) as a method of identifying physical locations and equipment such as buildings, central offices, poles, and antennas. Each CLLI code conforms to one of three basic formats (Network Entity, Network Support Site and Customer Site). Each format, in turn, determines how these six coding elements are used:

– Geographical Codes (Example: DNVR = Denver) Typically assigned to cities, towns, suburbs, villages, hamlets, military installations and international airports, geographical codes can also be mapped to mountains, bodies of water and satellities in fixed-earth orbit.

– Geopolitical Codes (Example: CO = Colorado) Typically assigned to countries, states and provinces, geopolitical and geographical codes can be combined to form a location identifyer that is unique worldwide.

– Network Site Codes (Example: 56 = A Central Office on Main Street) This element is used with geographical and geopolitcal codes to represent buildings, structures, enclosures or other locations at which there is a need to identify and describe one or more functional entities. This category includes central office buildings, business and commercial offices, certain microwave-radio relay buildings and earth stations, universities, hospitals, military bases and other government complexes, garages, sheds and small buildings, phone centers and controlled environmental vaults.

– Network Entity Codes (Example: DS0 = A digital switch) This element can be used with geographical, geopolitical and network-site codes to identify and describe functional categories of equipment, administrative groups or maintenance centers involved in the operations taking place at a given location.

– Network Support Site Codes (Example: P1234 = A telephone pole) This element can be used with geographical and geopolitical codes to identify and describe the location of international boundaries or crossing points, end points, fiber nodes, cable and facility junctions, manholes, poles, radio-equipment sites, repeaters and tall stations.

– Customer Site Codes (Example: 1A101 = A Customer) This element can be used with geographical and geopolitical codes to identify and describe customer locations associated with switched-service networks, centrex installations; Trunk forecasting, cable, carrier or fiber terminations, NCTE, CPE and PBX equipment, military installations, shopping malls, universities and hospitals.

Consider the real-life example of NYCMNY18DS0. The first four characters identify the place name (NYCM is New York City Manhattan). The following two characters identify the state, region, or territory (NY is New York). The remaining five chracters identify the specific item at that place (18DS0 is the AT&T 5E Digital Serving Office on West 18th Street, between Seventh and Eighth Avenues). Phone companies use CLLI Codes for a variety of purposes, including identifying and ordering private lines and trapping and tracing of annoying or threatening calls.

CLLI Code – Facility Identification codes provide unique identification of facilities (cable and carrier systems) between any two interconnected CLLI coded locations. The CLFI code is a variable length, mnemonic code with a maximum of 38 characters. Example: 101T1LSANCA03NWRKNJAA. This example says that there is a T-1 carrier connected between the Los Angeles, California Central Office to the Newark, New Jersey Central Office.





Want to know more?

You’re reading Boston’s Hub Tech Insider, a blog stuffed with years of articles about Boston technology startups and venture capital-backed companies, software development, Agile project management, managing software teams, designing web-based business applications, running successful software development projects, ecommerce and telecommunications.


About the author.

I’m Paul Seibert, Editor of Boston’s Hub Tech Insider, a Boston focused technology blog. You can connect with me on LinkedIn, follow me on Twitter, even friend me on Facebook if you’re cool. I own and am trying to sell a dual-zoned, residential & commercial Office Building in Natick, MA. I have a background in entrepreneurship, ecommerce, telecommunications and software development, I’m the Senior Technical Project Manager at eSpendWise, I’m a serial entrepreneur and the co-founder of Tshirtnow.net.

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

More Articles From Boston’s Hub Tech Insider:

What the Heck is a MPLS NGN? April 14, 2009

Posted by HubTechInsider in Fiber Optics, Telecommunications.
Tags: , , , ,
add a comment

Ever since I heard of MPLS NGN, I have been excited about the potential for the latest backbone networking technology and wanted to find out more about it. After reading through several books on MPLS NGNs, their architecture, the advantages, and what their potential for ILEC provisoners as well as CLEC access providers truly is, I think I am ready to outline the definition of a MPLS NGN, describe in an extremely non-technical way how they work, what they do, and what kinds of services they will enable in the future. I also try and expand just a bit on why I think they are so important, and what kinds of traditional weakness and deficiencies is the networks that have gone before they are able to address. And addressing on the fly is really at the heart of what a MPLS NGN does so well: 

General Architecture of a Multiprotocol Label Switching, Next Generation Network

MPLS is an acronym for Multiprotocol Label Switching. A NGN is a Next Generation Network. 

MPLS was created to address the weaknesses in traditional IP networks. Please recall that IP was designed to support “best effort” services. In other words, routers contain no inherent perception of the existence of or proper functioning of connections or rings; they see the ports and addresses that are available to their discovery via priority cues and routing tables. Simply put, IP routing lacks intelligence. So-called “Least cost” routing was designed to conduct traffic along the network using the shortest possible number of hops, which means traffic on the network could potentially take shorter, congested paths rather than the potentially more efficient longer, uncongested paths, leading to network “hotspots” and degrading network performance.

The MPLS environment, which has been gaining increased attention, was born out of Cisco’s tag switching. MPLS was originally proposed by the IETF (Internet Engineering Task Force) in 1997, with the core specifications being finalized in 2000. MPLS’s ability to plot static paths through an IP network gives service providers the traffic-engineering ability they crave, and the capability for provisioning (in the telecom sense of that word) VPNs is greatly strengthened. In fact, MPLS provides a very solid base for VPNs – and with increased capability for traffic engineering, service providers are able to tightly control and maintain QoS as well as optimize network utilization.

Although technically not an IP network, despite the fact that it can run in routers and uses IP routing protocols like OSPF and IS-IS, MPLS is one of the most significant developments in IP. To truly understand why this is, you also need to know that although it can also use repurposed ATM switch hardware, MPLS is, again technically, not an ATM network. 

MPLS is another type of network entirely: MPLS is a service-enabling technology. Think of MPLS like a general purpose, tunneling technology. As such, it is capable of carrying both IP and non-IP payloads. It uses what is called “label switching” to transport cells or packets over any data link layer throughout the network.

Much like the inband and out-of-band signaling on the PSTN, MPLS separates the forwarding, or transport, plane from the control plane. By so doing, it enables the capability to run the control plane on devices which cannot actually understand IP or recognize the boundaries of incoming packets. MPLS itself is an encapsulating protocol that has the ability to transport a number of other protocols. These protocols are encapsulated with a label that at each hop is swapped. The label is a number, or UID (Unique Identifier) that identifies a set of data flows along a particular logical link. They are only of local significance and they must change as a packets follow along a predetermined path – they literally switch.

MPLS’s potential to untie IP and optical switching under one route-provisioning umbrella is of great benefit, but it was designed to address two problems inherent in IP networks: IP sends all traffic over the same route between two points, and it cannot absolutely guarantee network resources, because as you will recall, IP is a connectionless protocol. These two shortcomings, in times of heavy network traffic, lead to some routes becoming underutilized while others become congested. Lacking control over the routing assignments, the provider cannot steer traffic from congested to less busy routes. So one key differentiator between IP and MPLS is the simple fact the MPLS networks can steer packets between two points along different paths depending upon their switching MPLS labels.