Broadband Internet Speed test

Synchronous optical networking, commonly known as SONET, is a standard for communicating digital information using lasers or light emitting diodes (LEDs) over optical fiber as defined by GR-253-CORE from Telcordia. It was developed to replace the PDH system for transporting large amounts of telephone and data traffic.

The more recent Synchronous Digital Hierarchy (SDH) standard developed by ITU (G.707 and its extension G.708) is built on experience in the development of SONET. Both SDH and SONET are widely used today; SONET in the U.S. and Canada, SDH in the rest of the world. SDH is growing in popularity and is currently the main concern with SONET now being considered as the variation.

SONET differs from PDH in that the exact rates that are used to transport the data are tightly synchronized to network based clocks. Thus the entire network operates synchronously. SDH was made possible by the existence of atomic clocks.

Both SONET and SDH can be used to encapsulate earlier digital transmission standards, such as the PDH standard, or used directly to support either ATM or so-called Packet over SONET networking.

The basic SONET signal operates at 51.840 Mbit/s and is designated STS-1 (Synchronous Transport Signal one). The STS-1 frame is the basic unit of transmission in SONET.

The Synchronous Transport Module level 1 (STM-1) is the basic signal rate of SDH.

The two major components of the STS-1 frame are the transport overhead and the synchronous payload envelope (SPE). The transport overhead (27 bytes) comprises the section overhead and line overhead. These bytes are used for signalling and measuring transmission error rates. The SPE comprises the payload overhead (9 bytes, used for end to end signalling and error measurement) and the payload of 774 bytes. The STS-1 payload is designed to carry a full DS-3 frame.

The entire STS-1 frame is 810 bytes. The STS-1 frame is transmitted in exactly 125 microseconds on a fiber-optic circuit designated OC-1 (optical carrier one). In practice the terms STS-1 and OC-1 are used interchangeably.

Three OC-1 (STS-1) signals are multiplexed by time-division multiplexing to form the next level of the SONET hierarchy, the OC-3 (STS-3), running at 155.52 Mbit/s. The multiplexing is performed by interleaving the bytes of the three STS-1 frames to form the STS-3 frame, containing 2430 bytes and transmitted in 125 microseconds. The STS-3 signal is also used as a basis for the SDH hierarchy, where it is designated STM-1.

Higher speed circuits are formed by successively aggregating multiples of slower circuits, their speed always being immediately apparent from their designation. For example, four OC-3 or STM-1 circuits can be aggregated to form a 622.08 Mbit/s circuit designated as OC-12 or STM-4.

The highest rate that is commonly deployed is the OC-192 or STM-64 circuit, which operates at rate of just under 10 Gbit/s. Speeds beyond 10 Gbit/s are technically viable and are under evaluation. Where fiber exhaust is a concern, multiple SONET signals can be transported over multiple wavelengths over a single fiber pair by means of Dense Wave Division Multiplexing (DWDM). Such circuits are the basis for all modern transatlantic cable systems and other long-haul circuits.

SONET/SDH was originally developed primarily to transport pulse-code modulated voice traffic in fixed rate 64kbit/s timeslots through a synchronous optical network. Therefore it was inefficient to transport the bursty packet traffic of the Ethernet world. By introducing virtual concatenation, SONET/SDH became capable of transmitting packet-sized data without bandwidth losses. The data payload like Ethernet is mapped to SDH/SONET using X.86 or Generic Framing Procedure(GFP) protocols. Also recent additions like Link Capacity Adjustment Scheme (LCAS) allows for dynamically changing the bandwidth.

From the Wikipedia article on SDH.

Gigabit Ethernet (GbE) is a term describing various technologies for implementing Ethernet networking at a nominal speed of one gigabit per second.

As a result of research done at Xerox Corporation in the early 1970s, Ethernet has evolved into the most widely implemented networking protocol today. Fast Ethernet increased speed from 10 to 100 megabits per second (Mbit/s). Gigabit Ethernet was the next iteration, increasing the speed to 1000 Mbit/s. It was standardized in June 1998.

Gigabit Ethernet is supported over both optical fiber and twisted pair cable. Physical layer standards include 1000BASE-T, 1 Gbit/s over Cat-5e copper cabling and 1000BASE-SX for short to medium distances over optic fiber.

Initially, Gigabit Ethernet was deployed in high-capacity backbone network links (for instance, on a high-capacity campus network). In 2000, Apple’s Power Mac G4 and PowerBook G4 featured the connection. Recently, it has become a built-in feature in many Pentium and Athlon motherboards. In May 2005, the Apple iMac G5 was redesigned to include Gigabit Ethernet. Its desktop and small-network applications include video editing and file transfers.

Gigabit Ethernet is not the fastest Ethernet standard, with the ratification of 10 Gigabit Ethernet in 2002, which is 10 times faster.

From the Gigabit Ethernet article in Wikipedia.
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Bluetooth is an industrial specification for wireless personal area networks (PANs). Bluetooth provides a way to connect and exchange information between devices like personal digital assistants (PDAs), mobile phones, laptops, PCs, printers and digital cameras via a secure, low-cost, globally available short range radio frequency. Bluetooth extends a violet beam to another Blutooth-capable device, allowing both devices to exchange information in 2 ways: chat and WiFi.

Bluetooth is a wirefree radio standard primarily designed for low power consumption, with a short range (power class depended 10 centimetres, 10 metres, 100 metres or up to 400 metres [1], ) and with a low-cost transceiver microchip in each device.

Bluetooth lets these devices talk to each other when they come in range, even if they are not in the same room, as long as they are within up to 100 metres (328 feet) of each other, dependent on the power class of the product. Products are available in one of three power classes:

1. Class 1 (100 mW) [still readily available]: It has the longest range at up to 100 metres (320 ft).
2. Class 2 (2.5 mW) [most common]: It allows a quoted transmission distance of 10 metres (32 ft).
3. Class 3 (1 mW) [rare]: It allows transmission of 10 cm (3.9 in), with a maximum of 1 metre (3.2 ft).

Bluetooth specification was first developed by Ericsson, and was later formalized by the Bluetooth Special Interest Group (SIG). The SIG was formally announced on May 20, 1999. It was established by Sony Ericsson, IBM, Intel, Toshiba and Nokia, and later joined by many other companies as Associate or Adopter members. Bluetooth is also IEEE 802.15.1.

Bluetooth 1.0 and 1.0B
Versions 1.0 and 1.0B had numerous problems and the various manufacturers had great difficulties in making their products interoperable. 1.0 and 1.0B also had mandatory Bluetooth Hardware Device Address (BD_ADDR) transmission in the handshaking process, rendering anonymity impossible at a protocol level, which was a major set back for services planned to be used in Bluetooth environments, such as Consumerium.

Bluetooth 1.1
In version 1.1:

many errata found in the 1.0B specifications were fixed.
There was added support for non-encrypted channels.

Bluetooth 1.2
This version is backwards compatible with 1.1 and the major enhancements include

Adaptive Frequency Hopping (AFH), which improves resistance to radio frequency interference by avoiding using crowded frequencies in the hopping sequence
Higher transmission speeds in practice
extended Synchronous Connections (eSCO), which improves voice quality of audio links by allowing retransmissions of corrupted packets.
Received Signal Strength Indicator (RSSI)
Host Controller Interface (HCI) support for 3-wire UART
HCI access to timing information for Bluetooth applications.

Bluetooth 2.0
This version is backwards compatible with 1.x. The main enhancement is the introduction of Enhanced Data Rate (EDR) of 2.1 Mbit/s. This has the following effects (Bluetooth SIG, 2004):

3 times faster transmission speed (up to 10 times in certain cases).
Lower power consumption through reduced duty cycle.
Simplification of multi-link scenarios due to more available bandwidth.
Further improved BER (Bit Error Rate) performance.

Read more in Wikipedia Bluetooth article.

A WDM system uses a multiplexer at the transmitter to join the signals together, and a demultiplexer at the receiver to split them apart. With the right type of fibre you can have a device that does both at once, and can function as an optical add-drop multiplexer. The optical filtering devices used in the modems are usually etalons, stable solid-state single-frequency Fabry-Perot interferometers.

The first WDM systems combined two signals and appeared around 1985. Modern systems can handle up to 160 signals and can expand a basic 10 Gbit/s fibre system to a theoretical total capacity of over 1.6 Tbit/s over a single fiber pair.

WDM systems are popular with telecommunications companies because they allow them to expand the capacity of the network without laying more fibre. By using WDM and optical amplifiers, they can accommodate several generations of technology development in their optical infrastructure without having to overhaul the backbone network. Capacity of a given link can be expanded by simply upgrading the multiplexers and demultiplexers at each end.

This is often done by using optical-to-electrical-to-optical translation at the very edge of the transport network, thus permitting interoperation with existing equipment with optical interfaces.

Most WDM systems operate on single mode fibre optical cables, which have a core diameter of 9 µm. Certain forms of WDM can also be used in multi-mode fibre cables (also known as premises cables) which have core diameters of 50 or 62.5 µm.

Early WDM systems were expensive and complicated to run. However, recent standardization and better understanding of the dynamics of WDM systems have made WDM much cheaper to deploy.

Optical receivers, in contrast to laser sources, tend to be wideband devices. Therefore the demultiplexer must provide the wavelength selectivity of the receiver in the WDM system.

The introduction of the ITU-T G.694.1 frequency grid in 2002 has made it easier to integrate WDM with older but more standard SONET systems. Today’s DWDM systems use 50 GHz or even 25 GHz channel spacing for up to 160 channel operation.

Recently the ITU has standardized a 20 nanometre channel spacing grid for use with CWDM (Coarse WDM), using the wavelengths between 1310 nm and 1610 nm. Many CWDM wavelengths below 1470 nm are considered “unusable” on older G.652 spec fibres, due to the increased attenuation in the 1310-1470 nm bands. Newer fibres which conform to the G.652.C and G.652.D standards, such as Corning SMF-28e and Samsung Widepass nearly eliminate the “water peak” attenuation peak and allow for full operation of all twenty ITU CWDM channels in metropolitan networks. For more information on G.652.C and .D compliant fibres please see the links at the bottom of the article:

DWDM systems are significantly more expensive than CWDM because the laser transmitters need to be significantly more stable than those needed for CWDM. Precision temperature control of laser transmitter is required in DWDM systems to prevent “drift” off a very narrow centre wavelength. In addition, DWDM tends to be used at a higher level in the communications hierarchy, for example on the Internet backbone and is therefore associated with higher modulation rates, thus creating a smaller market for DWDM devices with very high performance levels, and corresponding high prices. In another word, they are needed in small numbers and therefore not possible to amortize their development cost among a large number of transmitters.

Note: The term “Lambda” is also used interchangeably when referencing a specific wavelength of light.

From Wikipedia Wavelength-division multiplexing article.

Ericsson, the leader in third-generation mobile systems (3G), presented their Mobile Broadband Road show today at the Marriott Hotel, Green Community, Dubai.

The Road show attracted mobile operators from across the region, offering exciting prospects of introducing broadband on the go, in the Middle East whilst giving the delegates a glimpse of what Mobile Broadband users can look forward to in the very near future.

The operators attending the Road show included Saudi Telecom and Mobily from Saudi Arabia, MTC and Wataniya from Kuwait, Batelco from Bahrain, Syriatel from Syria, Faldete from Lebanon, Omantel and Nawras from Oman and Etisalat from UAE.

The Ericsson Mobile Broadband Road show was specially designed to demonstrate the manifold benefits of Mobile Broadband to the operators. With the tremendous evolution of mobiles and broadband, end users are not contented any more with accessing broadband on their PCs at home or work. They want it on their laptops and on their cell phones, wherever they happen to be.

Hence Mobile Broadband will address a growing need among end users for ‘everywhere, anytime’ access to email, Internet search engines, online music and videos, calendars and more. This will enable users to keep up with the online world, whether they’re traveling or commuting, which in turn means that companies can ensure that their employees are constantly in touch with their clients, suppliers and colleagues. By enabling them to be online at all times, companies can capitalize on mobility by increasing efficiency and hence bottom line.

By subscribing to Mobile Broadband, end users can expect significantly enhanced benefits. This will mean superior viewing experience with greater simplicity. Not only will the consumers be offered more capacity but they will now be available to access it at a lower overall cost. By subscribing to the service, consumers with 3G mobile will be able to download content heavy audio and video files as well as other large files and attachments. This will open up a whole new viewing experience to the end users and a new communication channel for marketers.

Ericsson is committed to customer trials featuring the mobile broadband systems, giving customers an opportunity to evaluate early on the significant benefits offered to both end users and operators alike. Ericsson is helping customers capitalize on this new revenue opportunity through a fast implementation and quick rollout. This has been made possible by combining Ericsson’s leadership in mobile systems with a market-leading portfolio of professional services ranging from network rollout to business consulting.

Ericsson is shaping the future of Mobile and Broadband Internet communications through its continuous technology leadership. Providing innovative solutions in more than 140 countries, Ericsson is helping to create the most powerful communication companies in the world.

From AME Info.