what is the number of bytes in a atm cell
ATM Adaptation Layer 2


CS). The basic component of AAL2 is the CPS packet. A CPS packet is an unanchored unit of data that can cross ATM cells and can start from anywhere in the payload of the ATM cell, other than the start field (STF). The STF is the first byte of the 48-byte ATM payload. The STF gives the byte index into the ATM cell where the first CPS packet in this cell begins. Byte 0 is the STF. The data from byte 1 ... (STF+1), would be the
17745895
Point-to-Point Protocol over Ethernet


FCS. To send 1544 bytes over ATM requires 33 48-byte ATM cells, since the available payload capacity of 32 cells × 48 bytes per cell = 1536 bytes is not quite enough. Compare this to the case of PPP + PPPoA which at 1500 + 2 (PPP) + 0 (PPPoA: RFC 2364 VC-MUX) + 8 (CPCS trailer) = 1510 bytes fits in 32 cells. So the real cost of choosing PPPoEoA plus RFC2684-LLC for 1500-byte IP packets is one additional ATM cell per IP packet, a
7322973
TDMoIP


CBR services over ATM. AAL1 operates by segmenting the continuous stream of TDM data into small 48-byte cells and inserting sequencing, timing, error recovery, and synchronization information into them. TDMoIP allows concatenation of any number of AAL1 cells into a packet (note that these are AAL1 cells and not ATM cells, i.e. they do not include the five-byte "cell tax"). By allowing multiple cells per packet, TDMoIP facilitates flexible tradeoffs of buffering delay (which decreases with fewer cells per packet) for bandwidth efficiency (
2651587
Point-to-Point Protocol over Ethernet


is only 32 or 36 bytes (depending on whether this is without or with the ethernet FCS option in PPPoEoA) so that a 1500 byte long packet including all overheads of PPP + PPPoEoA using VC-MUX equates to a total 1500 + 36 = 1536 bytes ATM payload if the FCS is present = 32 ATM cells exactly, thus saving an entire ATM cell. With short packets, the longer the header overheads the greater the likelihood of generating an additional ATM cell. A worst case might be sending 3 ATM cells instead
7322976
Asynchronous transfer mode


as a compromise between the two sides. 5-byte headers were chosen because it was thought that 10% of the payload was the maximum price to pay for routing information. ATM multiplexed these 53-byte cells instead of packets which reduced worst-case cell contention jitter by a factor of almost 30, reducing the need for echo cancellers. An ATM cell consists of a 5-byte header and a 48-byte payload. The payload size of 48 bytes was chosen as described above. ATM defines two different cell formats: user–network interface (UNI
2328338
AES47


. Each ATM virtual circuit negotiates the parameters of a stream at connection time. In addition to the same rate and number of channels (which may be more than the 2 supported by AES3), the negotiation covers the number of bits per sample and the presence of an optional data byte. The total must be 1, 2, 3, 4 or 6 bytes per sample, so it evenly divides the ATM cell size. AES3 uses 4 bytes per sample (24 bits of sample plus the optional data byte),
15091924
Point-to-Point Protocol over Ethernet


. The last one or two ATM cells contain padding bytes as required to ensure that each cell's payload is 48 bytes long. An example: In the case of a 1500-byte IP packet sent over AAL5/ATM with PPPoEoA and RFC2684-LLC, neglecting final cell padding for the moment, one starts with 1500 + 2 + 6 + 18 + 10 + 8 (AAL5 CPCS trailer) = 1544 bytes if the ethernet FCS is present, or else + 2 + 6 + 14 + 10 + 8 = 40 bytes with no
7322972
ATM Adaptation Layer 2


-layer packets into ATM cells, in this case packets of data containing voice and control information. AAL2 is further separated into two sub-layers that help with the mapping from upper layer services to ATM cells. These are named Service Specific Convergence Sub-layer (SSCS) and Common Part Sub-layer (CPS). The AAL2 protocol improves on other ATM Adaptation Layers, by packing lots of small packets efficiently into one standard-sized ATM cell of 53 bytes. A one-byte packet thus no longer has
17745891
Voice over IP


Asynchronous Transfer Mode (ATM) modems (Note: Non-ATM technologies such as 802.3ah also provide this capability). They use ATM Adaptation Layer 5 (AAL5) to segment each Ethernet packet into a series of 53-byte ATM cells for transmission, reassembling them back into Ethernet frames at the receiving end. A virtual circuit identifier (VCI) is part of the 5-byte header on every ATM cell, so the transmitter can multiplex the active virtual circuits (VCs) in any arbitrary order. Cells from the "same" VC
270454
ATM Adaptation Layer 2


straddled remainder of the previous ATM cell's final CPS packet. If there is no remainder from the previous cell, the STF is 0, and the first byte of the cell after the STF is also the location of the start of the first CPS packet. The format for the 1 byte STF at the beginning of the ATM cell is: The Offset Field carries the binary value of the offset, in octets, between the end of the P bit and the start of the CPCS-PDU Payload. Values of greater
17745896
Measuring network throughput


size cells. Each cell is 53 bytes long, with the first 5 bytes defined as the header, and the following 48 bytes as payload. Data networking commonly requires packets of data that are larger than 48 bytes, so there is a defined adaptation process that specifies how larger packets of data should be divided up in a standard manner to be carried by the smaller cells. This process varies according to the data carried, so in ATM nomenclature, there are different ATM Adaptation Layers. The process defined for most data is
2729855
Point-to-Point Protocol over Ethernet


+ 8 = 32 bytes (no FCS). However, the true overhead in terms of the total amount of ATM data sent is not simply a fixed additional value – it can "only be either zero or 48 bytes" (leaving aside scenario (iii) mentioned earlier, IP fragmentation). This is because ATM cells are fixed length with a payload capacity of 48 bytes, and adding a greater extra amount of AAL5 payload due to additional headers may require one more whole ATM cell to be sent containing the excess
7322971
CRC-based framing


a position in the receive data stream following the rules that the header CRC/HEC is correct and the byte offset correctly points to the next valid header CRC/HEC. StrataCom produced the first (pre-standard) ATM commercial product, the IPX. The IPX used 24 byte cells instead of ATM's 53 byte cells, and the field definitions were slightly different, but the basic idea of using short, fixed length cells was identical. StrataCom's first product had T1 (1.544 Mbit/s) based links which
13574153
ATM Adaptation Layer 2


than 47 are not allowed. The Sequence Number numbers the stream of CPCS-PDUs. The Parity bit is used to detect error in the OSF and SN fields. If the ATM cell has fewer than 47 bytes, the remainder will be filled by padding. One common adaptation of AAL2, AAL2u, doesn't use the STF field at all. In this case, one single CPS packet is aligned to the beginning of the cell. AAL2u is not used in standardized interfaces, but rather in proprietary equipment implementations where the
17745897
ATM Adaptation Layer 5


is divided into an integral number of ATM cells and reassembled into a packet before delivery to the receiving host. This process is known as Segmentation and Reassembly (see below). The last cell contains padding to ensure that the entire packet is a multiple of 48 octets long. The final cell contains up to 40 octets of data, followed by padding bytes and the 8-octet trailer. In other words, AAL5 places the trailer in the last 8 octets of the final cell where it can be found without knowing the length of
18442282
StrataCom


Holden, Jim Marggraff, Jon Masatsugu, David Owen and Pete Stonebridge. StrataCom's implementation of ATM was pre-standard and used 24 byte cells instead of standards-based ATM's 53 byte cells. However, many of concepts and details found in the ATM set of standards were derived directly from StrataCom's technology, including the use of CRC-based framing on its links. The IPX's first use was as a 4-1 voice compression system. It implemented Voice-Activity-Detection (VAD) and ADPCM
1963544
Point-to-Point Protocol over Ethernet


) of the run of ATM cells that make up the AAL5 payload packet. The total ATM payload overhead is 2 + 6 + 18 + 10 + 8 = 44 bytes in the LLC case if the Ethernet MAC FCS is present, or 2 + 6 + 14 + 10 + 8 = 40 bytes with no FCS. In the more efficient VC-MUX case the ATM payload overhead is 2 + 6 + 18 + 2 + 8 = 36 bytes (with FCS), or 2 + 6 + 14 + 2
7322970
ATM Adaptation Layer 2


an overhead ratio of 52 unused bytes out of 53 (i.e. 98%). Potentially, total of 11 one-byte CPS packets (plus 3/4 of a 12th CPS packet) could squeeze into a single cell. Of course, CPS packets can come in other sizes with other CIDs, too. When the transmission is ready, the CPS packets are all multiplexed together into a single cell and transported over standard ATM network infrastructure. The transport networks for ATM are well standardized fiber optic (SDH/Sonet, i.e. STM-1
17745892
Point-to-Point Protocol over Ethernet


14, and (ii) by using the RFC 2684 VC-MUX option, which reduces the 10 byte LLC overhead down to 2 bytes. It turns out that this can be a very valuable efficiency improvement. Using VC-MUX instead of LLC, the ATM payload overhead would be either 32 bytes (without Ethernet FCS) or 36 bytes (with FCS). ATM AAL5 requires that an 8-byte-long ‘CPCS’ trailer must always be present at the very end of the final cell (‘right justified’
7322969
Point-to-Point Protocol over Ethernet


ratio of 33:32. So for 1500 byte packets, PPPoEoA with LLC is ~3.125% slower than PPPoA or optimal choices of PPPoEoA header options. For some packet lengths the true additional effective DSL overhead due to choosing PPPoEoA compared with PPPoA will be zero if the extra header overhead is not enough to need an additional ATM cell at that particular packet length. For example, a 1492 byte long packet sent with PPP + PPPoEoA using RFC2684-LLC plus FCS gives us a total ATM payload of 1492 + 44 = 1536 bytes = 32 cells
7322974
Design by committee


the design of languages and technical standards, as demonstrated by USENET archives. An example of a technical decision said to be a typical result of design by committee is the Asynchronous Transfer Mode (ATM) cell size of 53 bytes. The choice of 53 bytes was political rather than technical. When the CCITT was standardizing ATM, parties from the United States wanted a 64-byte payload. Parties from Europe wanted 32-byte payloads. Most of the European parties eventually came around to the arguments made by the Americans, but France and a few
19491771
Voice over IP


cell-by-cell basis, a high priority packet would have to wait at most 53 byte times to begin transmission. There would be no need to reduce the interface MTU and accept the resulting increase in higher layer protocol overhead, and no need to abort a low priority packet and resend it later. ATM has substantial header overhead: 5/53 = 9.4%, roughly twice the total header overhead of a 1500 byte Ethernet frame. This "ATM tax" is incurred by every DSL user whether or not they take advantage
270456
Point-to-Point Protocol over Ethernet


of two because of a 44 byte header overhead compared with a 10 byte header overhead, so 50% more time taken to transmit the data. For example, a TCP ACK packet over IPv6 is 60 bytes long, and with overhead of 40 or 44 bytes for PPPoEoA + LLC this requires three 48 byte ATM cells’ payloads. As a comparison, PPPoA with overheads of 10 bytes so 70 bytes total fits into two cells. So the extra cost of choosing PPPoE/LLC over PPPoA is 50% extra data sent
7322977
ATM Adaptation Layer 2


multiplexing/demultiplexing, etc. that needs to be done for standard AAL2 either is too strenuous, is unsupported, or requires too much overhead (i.e. the 1 byte of STF) from the internal system's point of view. Most computer chips do not support AAL2, so stripping this layer away makes it easier to interwork between the ATM interface and the rest of the network. The following is diagram of the AAL2 ATM cell: A CPS packet has a 3-byte header and a payload of between one and 45 octets.
17745898
Point-to-Point Protocol over Ethernet


. PPPoEoA + VC-MUX would be fine though: with 32 or 36 byte overhead, our IP packet still fits in two cells. In all cases the most efficient option for ATM-based ADSL internet access is to choose PPPoA (RFC2364) VC-MUX. However, if PPPoEoA is required, then the best choice is always to use VC-MUX (as opposed to LLC) with no Ethernet FCS, giving an ATM payload overhead of 32 bytes = 2 bytes (for PPP) + 6 (for
7322978
Segmentation and reassembly


Segmentation and reassembly (SAR) is the process used to fragment and reassemble variable length packets into fixed length cells so as to allow them to be transported across asynchronous transfer mode (ATM) networks or other cell based infrastructures. Since ATM's payload is only 48 bytes, nearly every packet from any other protocol has to be processed in this way. Thus, it is an essential process for any ATM node. It is usually handled by a dedicated chip, called the SAR. The process is conceptually simple: an incoming
17330265
Distributed-queue dual-bus


MAN), where repairs may take longer than in a LAN and Wi-Fi because the damage may be inaccessible. The DQDB standard IEEE 802.6 was developed while ATM (Broadband ISDN) was still in early development, but there was strong interaction between the two standards. ATM cells and DQDB frames were harmonized. They both settled on essentially a 48-byte data frame with a 5-byte header. In the DQDB algorithm, a distributed queue was implemented by communicating queue state information via the header. Each node in a DQDB network maintains
19096516
Asynchronous transfer mode


48-byte cell payload, ATM is not suitable as a data link layer "directly" underlying IP (without the need for SAR at the data link level) since the OSI layer on which IP operates must provide a maximum transmission unit (MTU) of at least 576 bytes. SAR performance limits mean that the fastest IP router ATM interfaces are STM16 - STM64 which actually compares, while POS can operate at OC-192 (STM64) with higher speeds expected in the future, limits based on segmentation and reassembly (SAR). On
2328345
Multiprotocol Label Switching


will completely replace these technologies in the future, thus aligning these technologies with current and future technology needs. In particular, MPLS dispenses with the cell-switching and signaling-protocol baggage of ATM. MPLS recognizes that small ATM cells are not needed in the core of modern networks, since modern optical networks are so fast (, at 200 Gbit/s and beyond) that even full-length 1500 byte packets do not incur significant real-time queuing delays (the need to reduce such delays — "e.g.",
490643
Point-to-Point Protocol over Ethernet


). The amount of overhead added by PPPoEoA on a DSL link depends on the packet size because of (i) the absorbing effect of ATM cell-padding (discussed below), which completely cancels out additional overhead of PPPoEoA in some cases, (ii) PPPoEoA + AAL5 overhead which can cause an entire additional 53-byte ATM cell to be required, and (iii) in the case of IP packets, PPPoE overhead added to packets that are near maximum length ("‘MRU’") may cause IP fragmentation
7322966
Multiprotocol Label Switching


in the path, and encapsulation techniques are used to carry data across the connection. Excluding differences in the signaling protocols (RSVP/LDP for MPLS and PNNI:Private Network-to-Network Interface for ATM) there still remain significant differences in the behavior of the technologies. The most significant difference is in the transport and encapsulation methods. MPLS is able to work with variable length packets while ATM transports fixed-length (53 bytes) cells. Packets must be segmented, transported and re-assembled over an ATM network
490671
StrataCom


and sophistication of the frame relay offering. It also supported the 53 byte cells of the ATM standard instead the IPX's 24 byte cells. The original IPX product was also enhanced and re-introduced as the IGX. The cards in the original IPX system were: The cards in the second wave were The card in the third wave was StrataCom's first CEO was Steve Campbell who later went to Packeteer. Dick Moley, who came from ROLM Corporation, served as its CEO for most of its existence. Dave Sant originally
1963547
Asynchronous transfer mode


parties from Europe wanted 32-byte payloads because the small size (and therefore short transmission times) simplify voice applications with respect to echo cancellation. Most of the European parties eventually came around to the arguments made by the Americans, but France and a few others held out for a shorter cell length. With 32 bytes, France would have been able to implement an ATM-based voice network with calls from one end of France to the other requiring no echo cancellation. 48 bytes (plus 5 header bytes = 53) was chosen
2328337
Asynchronous transfer mode


”, i.e. set up on a per-call basis using signaling and disconnected when the call is terminated. Use of ATM technology was eventually largely superseded by Internet Protocol (IP)-only technology. Wireless and mobile ATM never established a significant foothold. In the ISO-OSI reference model data link layer (layer 2), the basic transfer units are generically called frames. In ATM these frames are of a fixed (53 octets or bytes) length and specifically called "cells". If a speech signal is reduced to packets
2328330
Circular buffer


the most common version of the circular buffer uses 8-bit bytes as elements. Some implementations of the circular buffer use fixed-length elements that are bigger than 8-bit bytes—16-bit integers for audio buffers, 53-byte ATM cells for telecom buffers, etc. Each item is contiguous and has the correct data alignment, so software reading and writing these values can be faster than software that handles non-contiguous and non-aligned values. Ping-pong buffering can be considered a very specialized circular buffer with exactly two large fixed-length elements.
13207433
Segmentation and reassembly


packet from another protocol to be transmitted across the ATM network is chopped up into segments that fit into 48-byte chunks carried as ATM cell payloads. At the far end, these chunks are fitted back together to reconstitute the original packet. The process is analogous to the fragmentation of IP packets on reaching an interface with a maximum transmission unit (MTU) less than the packet size and the subsequent reassembly of the original packet once the fragments have reached the original packet's destination. Since different types of data are encapsulated in different ways
17330266
Point-to-Point Protocol over Ethernet


Compare this with a vastly more header-efficient protocol, PPP + PPPoA RFC 2364 VC-MUX over ATM+DSL, which has a mere 10-byte overhead within the ATM payload. (In fact, just simply 10 bytes = 2 bytes for PPP + zero for RFC 2364 + 8 (AAL5 CPCS).) This figure of 44 bytes AAL5 payload overhead can be reduced in two ways: (i) by choosing the RFC 2684 option of discarding the 4-byte Ethernet MAC FCS, which reduces the figure of 18 bytes above to
7322968
Generic cell rate algorithm


) clock, which most hardware implementations are likely to already have. This replacement of the process with an RTC is possible because ATM cells have a fixed length (53 bytes), thus "T" is always a constant, and the calculation of the new bucket level (or of "TAT") does not involve any multiplication or division. As a result, the calculation can be done quickly in software, and while more actions are taken when a cell arrives than are taken by the token bucket, in terms
2351576
CRC-based framing


included a 5 bit header CRC, similar to ATM's 8 bit header CRC. T1 is a time-division multiplexing (TDM) protocol with 24 byte payloads carried in a 193 bit frame. The first bit of each frame carries one bit out of a special pattern. A receiver finds this special pattern by sequentially looking for the bit position in the receive data where a bit from this pattern shows up every 193rd byte. It was convenient for StrataCom to make the length of one cell equal to the length of one
13574154
Point-to-Point Protocol over Ethernet


exactly, and the overhead in this special case is no greater than if we were using the header-efficient PPPoA protocol, which would require 1492 + 2 + 0 + 8 = 1502 bytes ATM payload = 32 cells also. The case where the packet length is 1492 represents the optimum efficiency for PPPoEoA with RFC2684-LLC in ratio terms, unless even longer packets are allowed. Using PPPoEoA with the RFC2684 VC-MUX header option is always much more efficient than the LLC option, since the ATM overhead, as mentioned earlier,
7322975
General Bytes


General Bytes is a hardware and a software company that produces products related to Bitcoin, Blockchain and Open Source technologies. General Bytes was founded in 2013, is headquartered in Prague, Czech Republic with offices in Bradenton, Florida and is currently one of the largest Bitcoin ATM manufacturers in the world. General Bytes began selling its first Bitcoin ATM in 2014, and by 2018 there were over 3,000 in more than 70 countries. It was the first bitcoin machine company to incorporate near field communication (NFC) technology into their range of
17335049
Multiprotocol Label Switching


packet-switching clients which provide a datagram service model. It can be used to carry many different kinds of traffic, including IP packets, as well as native ATM, SONET, and Ethernet frames. A number of different technologies were previously deployed with essentially identical goals, such as Frame Relay and ATM. Frame Relay and ATM use "labels" to move frames or cells throughout a network. The header of the Frame Relay frame and the ATM cell refers to the virtual circuit that the frame or cell resides on.
490641
Asynchronous transfer mode


. Synchronization is also maintained at AAL1. AAL2 through AAL4 are used for variable bitrate (VBR) services, and AAL5 for data. Which AAL is in use for a given cell is not encoded in the cell. Instead, it is negotiated by or configured at the endpoints on a per-virtual-connection basis. Following the initial design of ATM, networks have become much faster. A 1500 byte (12000-bit) full-size Ethernet frame takes only 1.2 µs to transmit on a 10 Gbit/s network,
2328343
UTF-EBCDIC


due to the location of the square brackets. CCSID 37 has [] at hex BA and BB instead of at hex AD and BD respectively. Blue cells containing a large single-digit number are the start bytes for a sequence of that many bytes. The unbolded hexadecimal code point number shown in the cell is the lowest character value encoded using that start byte. This value can be greater than the value which would be obtained by following the start byte with continuation bytes which are all 65 (hex 0x41), if
13933550
Asynchronous transfer mode


delays while continuing to support datagram traffic. ATM broke up all packets, data, and voice streams into 48-byte chunks, adding a 5-byte routing header to each one so that they could be reassembled later. The choice of 48 bytes was political rather than technical. When the CCITT (now ITU-T) was standardizing ATM, parties from the United States wanted a 64-byte payload because this was felt to be a good compromise in larger payloads optimized for data transmission and shorter payloads optimized for real-time applications like voice;
2328336
Point-to-Point Protocol over ATM


VC-MUX option) = 10 bytes. It also avoids the issues that PPPoEoE suffers from, related to sometimes needing to use an IP MTU of 1492 bytes or less, lower than the standard 1500 bytes. The use of PPPoA over PPPoE is not geographically significant; rather, it varies by the provider's preference. Configuration of a PPPoA requires PPP configuration and ATM configuration. These data are generally stored in a cable modem or DSL modem, and may or may not be visible to—or configurable by—an
7323015
JIS X 0208


1 to 94) form a point, which is used to represent double-byte code points. A is expressed in the form "row-cell", the row and cell numbers being separated by a hyphen. For example, the character "" has a code point at row 16, cell 1, so its code number is represented as "16-01". In 7-bit JIS X 0208 (as might be switched to in JIS X 0202 / ISO-2022-JP), both bytes must be from the 94-byte range
2021918
Point-to-Point Protocol over Ethernet


, which also involves the first two considerations for both of the resulting IP fragments. However ignoring ATM and IP fragmentation for the moment, the protocol header overheads for ATM payload due to choosing PPP + PPPoEoA can be as high as 44 bytes = 2 bytes (for PPP) + 6 (for PPPoE) + 18 (Ethernet MAC, variable) + 10 (RFC 2684 LLC, variable) + 8 (AAL5 CPCS). This overhead is that obtained when using the LLC header option described in RFC 2684 for PPPoEoA.
7322967
Point-to-Point Protocol over ATM


(as does PPPoE) the encapsulation types: VC-MUX and LLC - see RFC 2364. If it is used as the connection encapsulation method on an ATM based network it can reduce overhead significantly compared with PPPoEoA – by between 0 and ~3.125% for long packets, depending on the packet length and also on the choices of header options in PPPoEoA – see PPPoEoA protocol overheads. This is because it uses headers that are short so imposes minimal overheads, 2 bytes for PPP and 8 bytes for PPPoA (with the RFC2364
7323014
Bitcoin ATM


in Regulations or in-effect as of January 2019. According to Coin ATM Radar, there are more than 2,342 Bitcoin ATMs in the United States as of January, 2018, with small shop owners earning a reported $300 a month for rental space. Transactions fees for ATM use are approximately 16 percent, while online transaction fees run about 7.5 percent. Part of the bitcoin ATMs operating in the US is imported from all over the world, for example from Prague. Czech company General Bytes has placed its machines in Las
5495795
Ataxia–telangiectasia


biochemical processes and metabolites can cause DSBs. When these breaks occur, ATM stops the cell from making new DNA (cell cycle arrest) and recruits and activates other proteins to repair the damage. Thus, ATM allows the cell to repair its DNA before the completion of cell division. If DNA damage is too severe, ATM will mediate the process of programmed cell death (apoptosis) to eliminate the cell and prevent genomic instability. In the absence of the ATM protein, cell-cycle check-point regulation and programmed cell
470124
Asynchronous transfer mode


packet discard (PPD) and early packet discard (EPD) have been created that will discard a whole series of cells until the next packet starts. This reduces the number of useless cells in the network, saving bandwidth for full packets. EPD and PPD work with AAL5 connections as they use the end of packet marker: the ATM user-to-ATM user (AUU) indication bit in the payload-type field of the header, which is set in the last cell of a SAR-SDU. Traffic shaping
2328355
UTF-8


into code points, the following rules apply: The following table summarizes usage of UTF-8 "code units" (individual bytes or octets) in a "code" page format. The upper half ( to ) is for bytes used only in single-byte codes, so it looks like a normal code page; the lower half is for continuation bytes ( to ) and leading bytes ( to ), and is explained further in the legend below. Orange cells with a large dot are continuation bytes. The hexadecimal number shown
13711918
JIS X 0208


of 0x21 (used for row or cell number 1) through 0x7E (used for row or cell number 94) – exactly corresponding to the range used for 7-bit ASCII printing characters, not counting the space. Accordingly, the encoded bytes are obtained by adding 0x20 (16) to each number. For instance, the above example of 16-01 ("亜") would be represented by the bytes codice_1. The 8-bit EUC-JP instead uses the range 0xA1 through 0xFE (setting the high bit to 1)
2021919
Jumbo frame


, ATM 9180 byte and 802.11 can transport 7935 byte MTUs. The IEEE 802.3 Ethernet standard only mandates support for 1500-byte MTU frames, 1518 byte total frame size (1522 byte with the optional IEEE 802.1Q VLAN/QoS tag). The use of 9000 bytes as preferred payload size for jumbo frames arose from discussions within the Joint Engineering Team of Internet2 and the U.S. federal government networks. Their recommendation has been adopted by all other national research and education networks. In order to meet this mandatory purchasing criterion, manufacturers have in turn
7785360
Computer


In almost all modern computers, each memory cell is set up to store binary numbers in groups of eight bits (called a byte). Each byte is able to represent 256 different numbers (2 = 256); either from 0 to 255 or −128 to +127. To store larger numbers, several consecutive bytes may be used (typically, two, four or eight). When negative numbers are required, they are usually stored in two's complement notation. Other arrangements are possible, but are usually not seen outside
16020584
Prefix code


is called a fixed-length code, or a block code (though the term block code is also used for fixed-size error-correcting codes in channel coding). For example, ISO 8859-15 letters are always 8 bits long. UTF-32/UCS-4 letters are always 32 bits long. ATM cells are always 424 bits (53 bytes) long. A fixed-length code of fixed length "k" bits can encode up to formula_1 source symbols. A fixed-length code is necessarily a prefix code
18072330
Asynchronous transfer mode


. If the MSB is 1, this is a management cell, and the other two bits indicate the type. (Network management segment, network management end-to-end, resource management, and reserved for future use.) Several ATM link protocols use the HEC field to drive a CRC-based framing algorithm, which allows locating the ATM cells with no overhead beyond what is otherwise needed for header protection. The 8-bit CRC is used to correct single-bit header errors and detect multi-bit header errors.
2328340
UTF-EBCDIC


this would result in an invalid overlong form. Orange cells with one dot are continuation bytes. The hexadecimal number shown after a "+" plus sign is the value of the 5 bits they add. Red cells indicate start bytes (for a sequence of that many bytes) which can never appear in properly encoded UTF-EBCDIC text, because any possible continuation would result in an invalid overlong form. For example, 0x76 is marked in red because even 0x76 0x73 (which maps to the UTF-8-Mod sequence 0xC2 0xBF) would
13933551
ATM Adaptation Layer 5


the packet; the final cell is identified by a bit in the ATM header (see below), and the trailer is always in the last 8 octets of that cell. When an application sends data over an ATM connection using AAL5, the host delivers a block of data to the AAL5 interface. AAL5 generates a trailer, divides the information into 48-octet pieces, and transfers each piece across the ATM network in a single cell. On the receiving end of the connection, AAL5 reassembles incoming cells into a packet, checks
18442283
JIS X 0208


", JIS X 0208-“compatible” products are not considered to exist. Terminology such as and is included in JIS X 0208, but the semantics of these terms vary from person to person. The first encoding byte corresponds to the row or cell number plus 0x20, or 32 in decimal (see below). Hence, the code set starting with 0x21 has a row number of 1, and its cell 1 has a continuation byte of 0x21 (or 33), and so forth. Some vendors use slightly different Unicode mapping
2021907
Data Matrix


A Data Matrix is a two-dimensional code consisting of black and white "cells" or dots arranged in either a square or rectangular pattern, also known as a matrix. The information to be encoded can be text or numeric data. Usual data size is from a few bytes up to 1556 bytes. The length of the encoded data depends on the number of cells in the matrix. Error correction codes are often used to increase reliability: even if one or more cells are damaged so it is unreadable, the message
2734168
TOP1


synthetic lethality between irinotecan-induced TOP1 inactivation and "MRE11" deficiency. There are a number of pre-clinical studies indicating synthetic lethality of irinotecan with other genetic or epigenetic DNA repair deficiencies common in cancers. For instance, the DNA repair gene "ATM" is frequently hypermethylated (silenced) in many cancers (see hypermethylation of ATM in cancers). A 2016 study showed that low expression of the ATM protein in gastric cancer cells "in vitro" and in a mouse model caused increased sensitivity to inactivation by irinotecan compared
6672867
DNA damage (naturally occurring)


strand break. This MRN complex recruits ATM to the site of damage. ATR and ATM phosphorylate various proteins that contribute to the damage repair system. The binding of ATR and ATM to damage sites on DNA lead to the recruitment of Chk1 and Chk2. These protein kinases send damage signals to the cell cycle control system to delay the progression of the cell cycle. Chk1 leads to the production of DNA repair enzymes. Chk2 leads to reversible cell cycle arrest. Chk2, as well as ATR/ATM, can activate p53,
10070933
Asynchronous transfer mode


) and network–network interface (NNI). Most ATM links use UNI cell format. ATM uses the PT field to designate various special kinds of cells for operations, administration and management (OAM) purposes, and to delineate packet boundaries in some ATM adaptation layers (AAL). If the most significant bit (MSB) of the PT field is 0, this is a user data cell, and the other two bits are used to indicate network congestion and as a general purpose header bit available for ATM adaptation layers
2328339
JIS X 0208


representations of the same single-byte code include 0x20 as hexadecimal, or 32 as a single decimal number. The double-byte codes are laid out in 94 numbered groups, each called a . Every row contains 94 numbered codes, each called a . This makes a total of 8836 (94 × 94) possible code points (although not all are assigned, see below); these are laid out in the standard in a 94-line, 94-column code table. A row number and a cell number (each numbered from
2021917
MPEG transport stream


is the basic unit of data in a transport stream, and a transport stream is merely a sequence of packets. Each packet starts with a sync byte and a header, that may be followed with optional additional headers; the rest of the packet consists of payload. All header fields are read as big-endian. Packets are 188 bytes in length, but the communication medium may add additional information. The 188-byte packet size was originally chosen for compatibility with Asynchronous Transfer Mode (ATM) systems. Each table or elementary stream
9872153
UTF-8


after a "+" plus sign is the value of the six bits they add. White cells are the leading bytes for a sequence of multiple bytes, the length shown at the left edge of the row. The text shows the Unicode blocks encoded by sequences starting with this byte, and the hexadecimal code point shown in the cell is the lowest character value encoded using that leading byte. Red cells must never appear in a valid UTF-8 sequence. The first two red cells (C0 and C1) could be used only
13711919
ATM serine/threonine kinase


cancer that has been ascribed to ATM's interaction and phosphorylation of BRCA1 and its associated proteins following DNA damage. Certain kinds of leukemias and lymphomas, including mantle cell lymphoma, T-ALL, atypical B cell chronic lymphocytic leukemia, and T-PLL are also associated with ATM defects. Mutations in the ATM gene are found at relatively low frequencies in sporadic cancers. According to "COSMIC", the "Catalogue Of Somatic Mutations In Cancer", the frequencies with which heterozygous mutations in ATM are found in common cancers include
16896047
ATM serine/threonine kinase


from errors during replication, by-products of metabolism, general toxic drugs or ionizing radiation. The cell cycle has different DNA damage checkpoints, which inhibit the next or maintain the current cell cycle step. There are two main checkpoints, the G1/S and the G2/M, during the cell cycle, which preserve correct progression. ATM plays a role in cell cycle delay after DNA damage, especially after double-strand breaks (DSBs). ATM together with NBS1 act as primary DSB sensor proteins. Different mediators
16896035
ATM Adaptation Layer 5


the CRC to ensure that all pieces arrived correctly, and passes the resulting block of data to the host software. The process of dividing a block of data into cells and regrouping them is known as ATM segmentation and reassembly (SAR). By separating the functions of segmentation and reassembly from cell transport, AAL5 follows the layering principle. The ATM cell transfer layer is classified as "machine-to-machine" because the layering principle applies from one machine to the next (e.g., between a host and a switch or
18442284
ATM serine/threonine kinase


ATM serine/threonine kinase, symbol ATM, is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks. It phosphorylates several key proteins that initiate activation of the DNA damage checkpoint, leading to cell cycle arrest, DNA repair or apoptosis. Several of these targets, including p53, CHK2, BRCA1, NBS1 and H2AX are tumor suppressors. The protein was named for the disorder ataxia–telangiectasia caused by mutations of ATM. Throughout the cell cycle DNA is monitored for damage. Damages result
16896034
ATM Adaptation Layer 5


final cell header can be thought of as an "end-to-end bit". Thus, the receiving AAL5 collects incoming cells until it finds one with an end-of-packet bit set. ATM standards use the term "convergence" to describe mechanisms that recognize the end of a packet. Although AAL5 uses a single bit in the cell header for convergence, other ATM adaptation layer protocols are free to use other convergence mechanisms. The AAL5 trailer does not include a "type" field. Thus, an
18442286
Leaky bucket


layer connection when the packets in the burst will arrive back-to-back. However, as in ATM, the tolerance may be applied to a lower rate, in that case the Sustainable Cell Rate (SCR), and the burst of packets (cells) can arrive at a higher rate, but less than the line rate of the physical layer, in that case the Peak Cell Rate (PCR). The MBS may then be the number of cells needed to transport a higher layer packet (see segmentation and
63395
ATM Adaptation Layer 2


The standard also defines a 64-octet mode, but this is not commonly used in real 3G networks. The 3-byte CPS header has following fields: The Channel Identifier identifies the user of the channel. The AAL2 channel is a bi-directional channel and the same channel identification value is used for both directions. The maximum number of multiplexed user channels is 248. As some channels are reserved for other uses, such as peer-to-peer layer management. CE : Channel Element CID = CE -E + ID The Length
17745899
Adipose tissue macrophages


Adipose tissue macrophages (abbr. ATMs) comprise tissue resident macrophages present in adipose tissue. Adipose tissue apart from adipocytes is composed of the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular endothelial cells and variety of immune cells. The latter ones are composed of mast cells, eosinophils, B cells, T cells and macrophages. The number of macrophages within adipose tissue differs depending on the metabolic status. As discovered by Rudolph Leibel and Anthony Ferrante et al. in 2003 at Columbia University, the percentage
7583239
Asynchronous transfer mode


ATM as an option. After the burst of the dot-com bubble, some still predicted that "ATM is going to dominate". However, in 2005 the ATM Forum, which had been the trade organization promoting the technology, merged with groups promoting other technologies, and eventually became the Broadband Forum. Wireless ATM, or mobile ATM, consists of an ATM core network with a wireless access network. ATM cells are transmitted from base stations to mobile terminals. Mobility functions are performed at an ATM switch in the core
2328362
Point-to-Point Protocol over Ethernet


when it finally arrived. While success on the second matter may be debated (some complain that 8 bytes per packet is too much) PPPoE clearly succeeded in bringing sufficient volume to drive the price for service down to what a home user would pay. The PPPoE has two distinct stages: Since traditional PPP connections are established between two end points over a serial link or over an ATM virtual circuit that has already been established during dial-up, all PPP frames sent on the wire are sure to reach the other end.
7322957
AES47


all samples in a cell (combined little-endian) form a sequencing word of 8, 12, 16, or 24 bits. Only the first 12 bits are defined. The first four bits of the sequencing word are a sequencing number, used to detect dropped cells. This increments by 1 for each cell transmitted. The second four bits are for error detection, with bit 7 being an even parity bit for the first byte. The third four bits, if present, are a second sequencing number which can be
15091926
Highway Addressable Remote Transducer Protocol


11. This is a one byte numerical value representing which command is to be executed. Command 0 and Command 11 are used to request the device number. Specifies the number of communication data bytes to follow. The status field is absent for the master and is two bytes for the slave. This field is used by the slave to inform the master whether it completed the task and what its current health status is. Data contained in this field depends on the command to be executed. Checksum is composed of an XOR of
11780077
ATM serine/threonine kinase


ATM may also be involved in mitochondrial homeostasis, as a regulator of mitochondrial autophagy (mitophagy) whereby old, dysfunctional mitochondria are removed. Increased ATM activity also occurs in viral infection where ATM is activated early during dengue virus infection as part of autophagy induction and ER stress response. A functional MRN complex is required for ATM activation after DSBs. The complex functions upstream of ATM in mammalian cells and induces conformational changes that facilitate an increase in the affinity of ATM towards its substrates, such as CHK2 and p53. Inactive ATM is
16896042
ATM serine/threonine kinase


present in the cells without DSBs as dimers or multimers. Upon DNA damage, ATM autophosphorylates on residue Ser1981. This phosphorylation provokes dissociation of ATM dimers, which is followed by the release of active ATM monomers. Further autophosphorylation (of residues Ser367 and Ser1893) is required for normal activity of the ATM kinase. Activation of ATM by the MRN complex is preceded by at least two steps, i.e. recruitment of ATM to DSB ends by the mediator of DNA damage checkpoint protein 1 (MDC1) which binds to MRE11, and the
16896043
ATM serine/threonine kinase


tumors were found to be methylated in the ATM gene promoter and there was strong inverse correlation between ATM promoter methylation and its protein expression (p  0.001). The ATM gene promoter was observed to be hypermethylated in 53% of small (impalpable) breast cancers and was hypermethylated in 78% of stage II or greater breast cancers with a highly significant correlation (P = 0.0006) between reduced ATM mRNA abundance and aberrant methylation of the ATM gene promoter. In non-small cell lung cancer (NSCLC), the ATM promoter
16896049
Linear probing


more similarly to completely random functions. For linear probing, 5-independence is enough to guarantee constant expected time per operation, while some 4-independent hash functions perform badly, taking up to logarithmic time per operation. Another method of constructing hash functions with both high quality and practical speed is tabulation hashing. In this method, the hash value for a key is computed by using each byte of the key as an index into a table of random numbers (with a different table for each byte position). The numbers from those table cells
4545990
Multiple myeloma


plasma cells, a gradual demethylation from stem cells to plasma cells was observed. The observed methylation pattern of CpG within intronic regions with enhancer-related chromatin marks in multiple myeloma is similar to undifferentiated precursor and stem cells. These results may represent a "de novo" epigenetic reprogramming in multiple myeloma, leading to the acquisition of a methylation pattern related to stemness. Mutations in a number of genes have been associated with this condition. These include ATM, BRAF, CCND1, DIS3, FAM46C, KRAS, NRAS and TP53.
5213770
Ataxia–telangiectasia


the ATM protein in cultured blood cells, an absence or deficiency of ATM function (kinase assay), or mutations in both copies of the cell’s ATM gene. These more specialized tests are not always needed, but are particularly helpful if a child’s symptoms are atypical. There are several other disorders with similar symptoms or laboratory features that physicians may consider when diagnosing A–T. The three most common disorders that are sometimes confused with A–T are: Each of these can be distinguished from A–T by the
470138
TTP/A


). The TTP/A bus is inactive for at least 13 bit times during each gap. A TTP/A round consists of one or more frames. A frame is a sequence of bytes transmitted by one node. A byte is transmitted in a slot consisting of 13 bit cells: one start-bit, eight data-bits, one parity, one stop-bits and a two bit cell wide inter byte gap. The rounds are independent from each other. Every round starts with a fireworks byte sent by
13252975
Ataxia–telangiectasia


ionizing radiation can damage cells in such a way that the body cannot repair them. The cells can cope normally with other forms of radiation, such as ultraviolet light, so there is no need for special precautions from sunlight exposure. A–T is caused by mutations in the ATM (ATM serine/threonine kinase or ataxia–telangiectasia mutated) gene, which was cloned in 1995. ATM is located on human chromosome 11 (11q22.3) and is made up of 69 exons spread across 150kb of genomic DNA.
470132
Voice over IP


of multiple virtual circuits – and few can. ATM's potential for latency reduction is greatest on slow links, because worst-case latency decreases with increasing link speed. A full-size (1500 byte) Ethernet frame takes 94 ms to transmit at 128 kbit/s but only 8 ms at 1.5 Mbit/s. If this is the bottleneck link, this latency is probably small enough to ensure good VoIP performance without MTU reductions or multiple ATM VCs. The latest generations of DSL, VDSL and VDSL2, carry Ethernet
270457
DNA-PKcs


alternative DNA repair pathway for double-strand breaks, non-homologous end joining (NHEJ). That is, in "ATM"-mutant cells, an inhibitor of DNA-PKcs causes high levels of apoptotic cell death. In "ATM" mutant cells, additional loss of DNA-PKcs leaves the cells without either major pathway (HRR and NHEJ) for repair of DNA double-strand breaks. Elevated DNA-PKcs expression is found in a large fraction (40% to 90%) of some cancers (the remaining fraction
4556503
Group-IB


reverse ATM attack" that allowed criminals to steal money from ATMs. "Money mules" (criminal payment agents) would deposit small sums into unembossed cards with legitimate accounts, immediately withdrawing what they'd put in. They also took a receipt from the ATM, which contained a payment reference number and the amount withdrawn. That information was sent to hackers who would use the data and their access to thousands of point of sale terminals, primarily based in the US and the Czech Republic, to create "a reversal operation"
98714
Plasma cell dyscrasias


underlie the evolution of a clinically silent plasma cell dyscrasia to an overt malignancy. The progressive genetic changes in clonal plasma cells include accumulating numerous single nucleotide polymorphisms, increases and decreases in gene and chromosome copy numbers, and chromosomal translocations. Genes affecting include those regulating genome stability itself (e.g. "KIF2B") as well as cellular activation, proliferation, and apoptosis (e.g. "CIDEC," "TP52, ATM, KRAS, NRAS, Wnt," and "NF-κB"). In the most malignant form of
11831810
Alternating Turing machine


successor configuration is found to be rejecting. An ATM decides a formal language in time formula_13 if, on any input of length , examining configurations only up to formula_13 steps is sufficient to label the initial configuration as accepting or rejecting. An ATM decides a language in space formula_15 if examining configurations which do not modify tape cells beyond the formula_15 cell from the left is sufficient. A language which is decided by some ATM in time formula_17 for some constant formula_18 is said to be in the class formula_19, and a language decided in
289799
TERF2


prevents t-loop formation, leading to excessive loss of telomeric DNA and early cell death. TERF2 plays a central role in preventing ATM kinase DNA damage response. It binds telomeric dsDNA and prevents telomeres from activating ATM kinase. This interaction of TERF2 with ATM is believed to be relevant to the mechanism by which TERF2 blocks ATM signaling. Because of its oligomeric nature, TERF2 could potentially cross-link ATM monomers and hold the kinase in its inactive dimeric state, thereby blocking amplification of the ATM signal at an early step in
6288222
UTF-8


for a two-byte encoding of a 7-bit ASCII character which should be encoded in one byte; as described below such "overlong" sequences are disallowed. The red cells in the F row (F5 to FD) indicate leading bytes of 4-byte or longer sequences that cannot be valid because they would encode code points larger than the U+10FFFF limit of Unicode (a limit derived from the maximum code point encodable in UTF-16), and FE and FF were never defined for any purpose in UTF-8. Pink cells are the leading
13711920
ATM Adaptation Layer 2


/AAL2's efficient handling of small packets contrasts with Ethernet's minimum payload of 46 bytes vs the 1-byte minimum size for an AAL2 CPS packet. AAL2 is the standard layer 2 protocol used in all Iu interfaces, i.e. the interfaces between UMTS base stations and UMTS Radio Network Controllers (RNCs) (Iu-B), inter-RNCs (Iu-R), UMTS RNCs and UMTS Serving GPRS Support Nodes (SGSNs) (Iu-PS), and UMTS RNCs and media gateways (MGWs) (Iu-
17745894
DNA-PKcs


absence of let-7a microRNA allows high expression of the HMGA2 protein and this would lead to defective expression of DNA-PKcs. DNA-PKcs can be up-regulated by stressful conditions such as in "Helicobacter pylori"-associated gastritis. After ionizing radiation DNA-PKcs was increased in the surviving cells of oral squamous cell carcinoma tissues. The ATM protein is important in homologous recombinational repair (HRR) of DNA double strand breaks. When cancer cells are deficient in ATM the cells are "addicted" to DNA-PKcs, important in the
4556502
Cell cycle checkpoint


of damage response is through the negative regulation of Plk1 by ATM/ATR, which in turn results in the stabilization of Wee1 and Myt1, which can then phosphorylate and inhibit cdc2, thus keeping the cell arrested in G2 until the damage is fixed. The mitotic spindle checkpoint occurs at the point in metaphase where all the chromosomes should/have aligned at the mitotic plate and be under bipolar tension. The tension created by this bipolar attachment is what is sensed, which initiates the anaphase entry. To do this, the sensing
17927941
DNA damage (naturally occurring)


triggering the damage response system, however more complex damage activates ATR and ATM, key protein kinases in the damage response system. DNA damage inhibits M-CDKs which are a key component of progression into Mitosis. In all eukaryotic cells, ATR and ATM are protein kinases that detect DNA damage. They bind to DNA damaged sites and activate Chk1, Chk2, and, in animal cells, p53. Together, these proteins make up the DNA damage response system. Some DNA damage does not require the recruitment of ATR and ATM
10070931
ATM serine/threonine kinase


type ATM gene is expressed at a four-fold increased level in human testes compared to somatic cells (such as skin fibroblasts). In both mice and humans, ATM deficiency results in female and male infertility. Deficient ATM expression causes severe meiotic disruption during prophase I. In addition, impaired ATM-mediated DNA DSB repair has been identified as a likely cause of aging of mouse and human oocytes. Expression of the ATM gene, as well as other key DSB repair genes, declines with age in mouse and human oocytes and
16896052