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| Term |
Description |
| backbone |
The part of a communications network that handles the major traffic using the highest-speed, and often longest paths in the network. On the Internet, a backbone is a set of paths that local networks connect to for long-distance interconnection. |
| backdoor |
backdoor refers to a port/channel crackers use to access your system. As a rule, it might be easy for a skilled cracker to find a backdoor in a system that is insufficiently protected. |
| backhaul |
backhaul (in telecommunications) refers to sending data over long distances to the global network backbone/internet.
Backhaul generally refers to the commercial wholesale bandwidth side of the network that communicates with the global Internet. |
| bandwidth |
bandwidth is the amount of data that can be carried in a given time period over a network.
More technically, bandwidth is the width of the range of frequencies that an electronic signal occupies on a given transmission medium. In digital systems, bandwidth is usually expressed as bps (bits per second), Kbps (Kilobits/second or Mbps (Megabits / second). In analog systems, it's the number of cycles of change per second, or hertz. |
| baud |
baud is essentially the rate at which bits are transmitted over a communication link. Baud is the number of transitions (used to encode bits) that take place in one second.
However, since such single state change can involve more than a single bit of data, the term bps (bits per second) has replaced baud as a better expression of data transmission speed. |
| BDP |
The Bandwidth*Delay Product, or BDP for short determines the amount of data that can be in transit in the network. It is the product of the available bandwidth and the latency, or RTT. BDP is a very important concept in a Window based protocol such as TCP. It plays an especially important role in high-speed / high-latency networks, such as most broadband internet connections. It is one of the most important factors of tweaking TCP in order to tune systems to the type of network used.
The BDP simply states that:
BDP (bits) = total_available_bandwidth (bits/sec) x round_trip_time (sec)
or, since RWIN/BDP is usually in bytes, and latency is measured in milliseconds:
BDP (bytes) = total_available_bandwidth (KBytes/sec) x round_trip_time (ms)
What does it all mean? The TCP Window is a buffer that determines how much data can be transferred before the server waits for acknowledgement. It is in essence bound by the BDP. If the BDP (or RWIN) is lower than the product of the latency and available bandwidth, we can't fill the line since the client can't send acknowledgements back fast enough. A transmission can't exceed the (RWIN / latency) value, so RWIN needs to be large enough to fit the maximum_available_bandwidth x maximum_anticipated_delay. |
| beamforming |
beamforming is a signal processing technique used in wireless communications, sonars and radars for directional signal tramsmission and reception. Beamforming is achieved by combining elements in a transmitter/antenna array in a way where signals at particular angles experience constructive interference, while others experience destrictive interference. The improvement compared with an omnidirectional reception/transmission is known as the receive/transmit gain (or loss).
There are two different methods as applicable to Wi-Fi: on-chip and on-antenna beamforming.
On-chip beamforming works by not only boosting total power gain by having multiple antennas in play, but also phasing the antenna signals so that a higher signal "beam" is cast in the receiver's direction while less energy can be expended in other directions.
On-antenna beamforming uses a number of antennas and analyzes trasmitted packets to asses signal perfomance. The access point monitors connections in real-time and modifies beams on the fly to fit dynamic conditions. Antennas that need signal boosting get boosted while those that don't are attenuated. |
| BGP |
BGP (Border Gateway Protocol) is a routing protocol that enables groups of routers (called autonomous systems) to communicate and share routing information establishing efficient, loop-free routes while using their own internal routing policies. BGP is commonly used within and between Internet Service Providers (ISPs). For customers, BGP allows for using unique routing policies internally, as well as connecting to multiple ISPs. The protocol is defined in RFC 1771. |
| BIOS |
BIOS (Basic Input/Output System) is the program which starts up your computer and communicates between the devices (such as your hard drive, keyboard, video card) and the system. BIOS is normally stored in an EPROM (Eraseable Programmable Read Only Memory) chip. |
| bit shift |
bit shift is a binady number operation, that moves (shifts) the bits in a number to the left or right.
Each bit shifted increases/decreases the value by a power of two. Eg a shift of 1 to the left will double the value, a shift to 2 to the right will quarter it. |
| BLEC |
Building-focused Local Exchange Carrier |
| blog |
blog (short for short for weblog) simply refers to a frequent, chronological publication of personal thoughts and web links.
The term can be used to describe a type of a publicly accessible personal journal, or some type of discusison community about particular issues (where there can be more than one author). In either case, it is a regularly updated online journal of information and opinions.
The activity of updating a blog is referred to as "blogging," and someone who keeps a blog is a "blogger." |
| Bluetooth |
Bluetooth (BT) is a short-range wireless technology that connects two devices with radio signals. Unlike WiFi, it is primarily designed for short range (up to 30 feet). Bluetooth basic rate speeds are ~720Kbps.
Common uses include connecting Bluetooth-enabled phones to headsets, PDA wireless networking, automobile interface with a phone for hands-free operation, wireless mice/keyboards, etc.
Revisions:
Bluetooth 1.x - basic rate bluetooth, max data rate 1Mbps
Bluetooth 2.x - basic rate + EDR(optional), max data rate with EDR 3Mbps, better pairing.
Bluetooth 3.x - basic rate + EDR(optional) + HS(optional), further speed improvements using 802.11 protocol adaptation layer.
Bluetooth 4.x - basic rate + EDR(optional) + HS(optional) + LE(optional). Low energy devices support for lower power consumption, a.k.a. Bluetooth Smart.
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| BoD |
BoD (Bandwidth on Demand) is a technique used in data communication to temporarily boost the capacity of a link. The technique is commonly used in wide area networks. Instead of explicitly allocating capacity during construction of the network, BoD enables network capacity to be increased on-demand and immediately reduced when the need has been addressed. This best suits applications with fluctuating bandwidth needs.
BoD is a tailored product for customers who require Internet Access in varied amounts at varying times. It caters additional bandwidth needs when required by the customer. When more capacity is needed, routers that provide bandwidth-on-demand can establish links on demand and then bring the line down when traffic demand is lower, allowing for a more cost-effective solution. |
| bonding |
Bonding combines two or more physical circuits into one logical circuit, for example, two T1s (1.54 Mbps each) can be combined to form a 3Mbps circuit. Bonding can be accomplished on the physical level through multiplexing or through hardware such as Tiara equipment. |
| Boot |
Boot - to start a device and cause it to start executing instructions. |
| BPI |
BPI (Baseline Privacy Interface)
DOCSIS required encryption standard used to protect users and their data. BPI uses a public/private key exchange system to encrypt data that is transmitted between the cable modem and the CMTS.
Also: Bits Per Inch - A measurement of the recording density of a disk or tape.
Also: British Phonographic Industry
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| BPL |
BPL (Broadband over Power Lines) is an emerging internet access technology that utilizes existing power lines to transport data at broadband speeds.
The IEEE 1901 (1901-2010) standard replaced a number of previous powerline specifications. It prevents interference when the different BPL implementations are operated within close proximity.
Related: IEEE 1905.1 heterogeneous networking, IEEE P1909.1 smart grid standards |
| bps |
bits per second, as oposed to Bps (Bytes per seccond). |
| bricked |
bricked - when used in reference to electronics, "brick" describes a device that connot function in any capacity (such as a device with damaged firmware). This usage derives from teh fact that many electronic devices are vaguely brick-shaped, and would be useful only as bricks if they do not function.
Bricking implies that a software error has rendered the device completely useless without some hardware replacement, or a complex procedure, often requiring dificult to obtain cables, software, shipping it back to the manufacturer, etc. |
| broadband |
broadband is a term that is being used interchangeably with high-speed. More specifically, it desctibes a wideband high-speed data transmission that employs only one wire, which is able to carry multiple channels at once (as opposed to narrowband, or baseband which transmits one channel at a time).
Various definitions of broadband assign a different minimum data rate to the term, however it is generally agreed that DSL and Cable are broadband services in the downstream direction. |
| BSOD |
BSOD (Blue Screen of Death) - This term is closely related to the older Black Screen of Death but much more common (many non-hackers have picked it up). Due to the extreme fragility and bugginess of MS Windows, misbehaving applications can crash the OS. The Blue Screen of Death, sometimes decorated with hex error codes, is what you get when this happens. |
| bufferbloat |
Bufferbloat is the undesirable increase in latency caused by a router or other network equipment buffering too much data.
Bufferbloat can also refer to an increase in latency (measure of round trip delay) when an internet connection is fully utilized.
Note that a bufferbloat has an effect only when that particular buffer is actually filled. In other words, oversized buffers have a damaging effect only when the link they buffer becomes a bottleneck. |
| Term |
Description |
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