Synchronous optical networking

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digital line and the regenerator section. The regenerator section refers to the section and photonic layers. The photonic layer is the lowest SONET layer and it is responsible for transmitting the bits to the physical medium. The section layer is responsible for generating the proper STS-N frames which are to be transmitted across the physical medium. It deals with issues such as proper framing, error monitoring, section maintenance, and orderwire. The line layer ensures reliable transport of the payload and overhead generated by the path layer. It provides synchronization and multiplexing for multiple paths. It modifies overhead bits relating to quality control. The path layer is SONET's highest level layer. It takes data to be transmitted and transforms them into signals required by the line layer, and adds or modifies the path overhead bits for performance monitoring and protection switching.

458:, therefore, there are 8,000 frames per second on a 155.52 Mbit/s OC-3 fiber-optic circuit. The STM-1 frame consists of overhead and pointers plus information payload. The first nine columns of each frame make up the section overhead and administrative unit pointers, and the last 261 columns make up the information payload. The pointers (H1, H2, H3 bytes) identify administrative units (AU) within the information payload. Thus, an OC-3 circuit can carry 150.336 Mbit/s of payload, after accounting for the overhead. 340: (μs), compared to a frame rate of 125 μs; many competing protocols buffer the data during such transits for at least one frame or packet before sending it on. Extra padding is allowed for the multiplexed data to move within the overall framing, as the data is clocked at a different rate than the frame rate. The protocol is made more complex by the decision to permit this padding at most levels of the multiplexing structure, but it improves all-around performance. 1271:

ring on the protection fibers. BLSRs trade cost and complexity for bandwidth efficiency, as well as the ability to support "extra traffic" that can be pre-empted when a protection switching event occurs. In four-fiber ring, either single node failures, or multiple line failures can be supported, since a failure or maintenance action on one line causes the protection fiber connecting two nodes to be used rather than looping it around the ring.

1370: 38: 437: 885: 307:(POS) networking. Therefore, it is inaccurate to think of SDH or SONET as communications protocols in and of themselves; they are generic, all-purpose transport containers for moving both voice and data. The basic format of a SONET/SDH signal allows it to carry many different services in its virtual container (VC), because it is bandwidth-flexible. 1215:, involves four fibers: two working fibers (one in each direction), and two protection fibers. Switching is based on the line state, and may be unidirectional (with each direction switching independently), or bidirectional (where the network elements at each end negotiate so that both directions are generally carried on the same pair of fibers). 446: 230: 420:. For both SONET and SDH, this is often represented by displaying the frame graphically: as a block of 90 columns and nine rows for STS-1, and 270 columns and nine rows for STM1/STS-3c. This representation aligns all the overhead columns, so the overhead appears as a contiguous block, as does the payload. 673:) with the same line rate as OC-192/STM-64 (9,953,280 kbit/s). The WAN PHY variant encapsulates Ethernet data using a lightweight SDH/SONET frame, so as to be compatible at a low level with equipment designed to carry SDH/SONET signals, whereas the LAN PHY variant encapsulates Ethernet data using 1223:

In unidirectional path-switched rings (UPSRs), two redundant (path-level) copies of protected traffic are sent in either direction around a ring. A selector at the egress node determines which copy has the highest quality, and uses that copy, thus coping if one copy deteriorates due to a broken fiber

461:

Carried within the information payload, which has its own frame structure of nine rows and 261 columns, are administrative units identified by pointers. Also within the administrative unit are one or more virtual containers (VCs). VCs contain path overhead and VC payload. The first column is for path

210:

format. The primary difficulty in doing this prior to SONET/SDH was that the synchronization sources of these various circuits were different. This meant that each circuit was actually operating at a slightly different rate and with different phase. SONET/SDH allowed for the simultaneous transport of

423:

The internal structure of the overhead and payload within the frame differs slightly between SONET and SDH, and different terms are used in the standards to describe these structures. Their standards are extremely similar in implementation, making it easy to interoperate between SDH and SONET at any

855:

Note that the data-rate progression starts at 155 Mbit/s and increases by multiples of four. The only exception is OC-24, which is standardized in ANSI T1.105, but not a SDH standard rate in ITU-T G.707. Other rates, such as OC-9, OC-18, OC-36, OC-96, and OC-1536, are defined but not commonly

680:

However, 10 Gigabit Ethernet does not explicitly provide any interoperability at the bitstream level with other SDH/SONET systems. This differs from WDM system transponders, including both coarse and dense wavelength-division multiplexing systems (CWDM and DWDM) that currently support OC-192 SONET

1287:

depending upon the traffic pattern on the ring. In the best case, all traffic is between adjacent nodes. The worst case is when all traffic on the ring egresses from a single node, i.e., the BLSR is serving as a collector ring. In this case, the bandwidth that the ring can support is equal to the

1270:

Bidirectional line-switched ring (BLSR) comes in two varieties: two-fiber BLSR and four-fiber BLSR. BLSRs switch at the line layer. Unlike UPSR, BLSR does not send redundant copies from ingress to egress. Rather, the ring nodes adjacent to the failure reroute the traffic "the long way" around the

864:

The physical layer refers to the first layer in the OSI networking model. The ATM and SDH layers are the regenerator section level, digital line level, transmission path level, virtual path level, and virtual channel level. The physical layer is modeled on three major entities: transmission path,

1450:(VCAT) allows for a more arbitrary assembly of lower-order multiplexing containers, building larger containers of fairly arbitrary size (e.g., 100 Mbit/s) without the need for intermediate network elements to support this particular form of concatenation. Virtual concatenation leverages the 1434:

voice traffic. The ability to transport ATM traffic was another early application. In order to support large ATM bandwidths, concatenation was developed, whereby smaller multiplexing containers (e.g., STS-1) are inversely multiplexed to build up a larger container (e.g., STS-3c) to support large

1202:

SONET and SDH have a limited number of architectures defined. These architectures allow for efficient bandwidth usage as well as protection (i.e. the ability to transmit traffic even when part of the network has failed), and are fundamental to the worldwide deployment of SONET and SDH for moving

449:

For the sake of simplicity, the frame is shown as a rectangular structure of 270 columns and nine rows. The first three rows and nine columns contain regenerator section overhead (RSOH) and the last five rows and nine columns contain multiplex section overhead (MSOH). The fourth row from the top

1355:

A timing loop occurs when network elements in a network are each deriving their timing from other network elements, without any of them being a "master" timing source. This network loop will eventually see its own timing "float away" from any external networks, causing mysterious bit errors—and

1147:

Traditional regenerators terminate the section overhead, but not the line or path. Regenerators extend long-haul routes in a way similar to most regenerators, by converting an optical signal that has already traveled a long distance into electrical format and then retransmitting a regenerated

963:

In order to allocate bandwidth throughout a network, each network element must be configured. Although this can be done locally, through a craft interface, it is normally done through a network management system (sitting at a higher layer) that in turn operates through the SONET/SDH network

252:, and SDH in the rest of the world. Although the SONET standards were developed before SDH, it is considered a variation of SDH because of SDH's greater worldwide market penetration. SONET is subdivided into four sublayers with some factor such as the path, line, section and physical layer. 1356:

ultimately, in the worst cases, massive loss of traffic. The source of these kinds of errors can be hard to diagnose. In general, a network that has been properly configured should never find itself in a timing loop, but some classes of silent failures could nevertheless cause this issue.

1438:

One problem with traditional concatenation, however, is inflexibility. Depending on the data and voice traffic mix that must be carried, there can be a large amount of unused bandwidth left over, due to the fixed sizes of concatenated containers. For example, fitting a 100 Mbit/s

1484:

for large customers, and is no longer competitive in the supply of private circuits. Development has stagnated for the last decade (2020) and both suppliers of equipment and operators of SONET/SDH networks are migrating to other technologies such as OTN and wide area Ethernet.

404:, and instead of being transmitted before the payload, is interleaved with it during transmission. Part of the overhead is transmitted, then part of the payload, then the next part of the overhead, then the next part of the payload, until the entire frame has been transmitted. 503:

Called multiplex section overhead (MSOH) in SDH: 45 octets containing information about error correction and Automatic Protection Switching messages (e.g., alarms and maintenance messages) as may be required within the network. The error correction is included for STM-16 and

319:

SONET is a set of transport containers that allow for delivery of a variety of protocols, including traditional telephony, ATM, Ethernet, and TCP/IP traffic. SONET therefore is not in itself a native communications protocol and should not be confused as being necessarily

1443:

connection inside a 155 Mbit/s STS-3c container leads to considerable waste. More important is the need for all intermediate network elements to support newly introduced concatenation sizes. This problem was overcome with the introduction of Virtual Concatenation.

620:

Higher-speed circuits are formed by successively aggregating multiples of slower circuits, their speed always being immediately apparent from their designation. For example, four STS-3 or AU4 signals can be aggregated to form a 622.08 Mbit/s signal designated

473:(MSOH). The overheads contain information from the transmission system itself, which is used for a wide range of management functions, such as monitoring transmission quality, detecting failures, managing alarms, data communication channels, service channels, etc. 371:

channel, which can carry 672 64-kbit/s voice channels. In SONET, the STS-3c signal is composed of three multiplexed STS-1 signals; the STS-3c may be carried on an OC-3 signal. Some manufacturers also support the SDH equivalent of the STS-1/OC-1, known as STM-0.

976:

Network elements have a very large set of standards for performance management. The performance-management criteria allow not only monitoring the health of individual network elements, but isolating and identifying most network defects or outages. Higher-layer

367:, operating at 51.84 Mbit/s—exactly one third of an STM-1/STS-3c/OC-3c carrier. This speed is dictated by the bandwidth requirements for PCM-encoded telephonic voice signals: at this rate, an STS-1/OC-1 circuit can carry the bandwidth equivalent of a standard 416:. In the case of an STS-3c/STM-1, which operates three times faster than an STS-1, nine octets of overhead are transmitted, followed by 261 octets of payload. This is also repeated nine times until 2,430 octets have been transmitted, also taking 125 1174:(ADMs) are the most common type of network elements. Traditional ADMs were designed to support one of the network architectures, though new generation systems can often support several architectures, sometimes simultaneously. ADMs traditionally have a 1060:

SDH has been mainly managed using the Q3 interface protocol suite defined in ITU recommendations Q.811 and Q.812. With the convergence of SONET and SDH on switching matrix and network elements architecture, newer implementations have also offered TL1.

1488:

British Telecom has recently (March 2020) closed down their KiloStream and Mega Stream products which were the last large scale uses of the BT SDH. BT has also ceased new connections to their SDH network which indicates withdrawal of services soon.

427:

In practice, the terms STS-1 and OC-1 are sometimes used interchangeably, though the OC designation refers to the signal in its optical form. It is therefore incorrect to say that an OC-3 contains 3 OC-1s: an OC-3 can be said to contain 3 STS-1s.

1274:

BLSRs can operate within a metropolitan region or, often, will move traffic between municipalities. Because a BLSR does not send redundant copies from ingress to egress, the total bandwidth that a BLSR can support is not limited to the line rate

411:

in size, while the STM-1/STS-3c frame is 2,430 octets in size. For STS-1, the frame is transmitted as three octets of overhead, followed by 87 octets of payload. This is repeated nine times, until 810 octets have been transmitted, taking

226:), the internal complex structure previously used to transport circuit-oriented connections was removed and replaced with a large and concatenated frame (such as STS-3c) into which ATM cells, IP packets, or Ethernet frames are placed. 440:

An STM-1 frame. The first nine columns contain the overhead and the pointers. For the sake of simplicity, the frame is shown as a rectangular structure of 270 columns and nine rows but the protocol does not transmit the bytes in this

331:

interleaved between the data in a complex way. This permits the encapsulated data to have its own frame rate and be able to "float around" relative to the SDH/SONET frame structure and rate. This interleaving permits a very low

1194:(DCSs or DXCs) support numerous high-speed signals, and allow for cross-connection of DS1s, DS3s and even STS-3s/12c and so on, from any input to any output. Advanced DCSs can support numerous subtending rings simultaneously. 462:

overhead; it is followed by the payload container, which can itself carry other containers. Administrative units can have any phase alignment within the STM frame, and this alignment is indicated by the pointer in row four.

1134:

With advances in SONET and SDH chipsets, the traditional categories of network elements are no longer distinct. Nevertheless, as network architectures have remained relatively constant, even newer equipment (including

2011:

Hassan, Rosilah, James Irvine, and Ian Glover. "Design and Analysis of Virtual Bus Transport Using Synchronous Digital Hierarchy/Synchronous Optical Networking." Journal of Computer Science 4.12 (2008): 1003-011.

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protocol. TL1 is a telecom language for managing and reconfiguring SONET network elements. The command language used by a SONET network element, such as TL1, must be carried by other management protocols, such as

315:

SONET and SDH often use different terms to describe identical features or functions. This can cause confusion and exaggerate their differences. With a few exceptions, SDH can be thought of as a superset of SONET.

1182:, which can consist of electrical as well as optical interfaces. The low-speed side takes in low-speed signals, which are multiplexed by the network element and sent out from the high-speed side, or vice versa. 640:

circuit, which operates at rate of just under 38.5 Gbit/s. Where fiber exhaustion is a concern, multiple SONET signals can be transported over multiple wavelengths on a single fiber pair by means of

1328:

or a satellite-derived clock by a device in the same central office as the network element. The interface is often a DS1, with sync-status messages supplied by the clock and placed into the DS1 overhead.

454:

The Synchronous Transport Module, level 1 (STM-1) frame is the basic transmission format for SDH—the first level of the synchronous digital hierarchy. The STM-1 frame is transmitted in exactly 125

222:(ATM) frames also known as cells. It quickly evolved mapping structures and concatenated payload containers to transport ATM connections. In other words, for ATM (and eventually other protocols such as 613:(STS-3), running at 155.52 Mbit/s. The signal is multiplexed by interleaving the bytes of the three STS-1 frames to form the STS-3 frame, containing 2,430 bytes and transmitted in 125 211:

many different circuits of differing origin within a single framing protocol. SONET/SDH is not a complete communications protocol in itself, but a transport protocol (not a 'transport' in the

1314:. Typically, a network element uses the highest quality stratum available to it, which can be determined by monitoring the synchronization status messages (SSM) of selected clock sources. 575:

if it processes the line overhead. Note that wherever the line or path is terminated, the section is terminated also. SONET regenerators terminate the section, but not the paths or line.

852:

User throughput must not deduct path overhead from the payload bandwidth, but path-overhead bandwidth is variable based on the types of cross-connects built across the optical system.

356:(Mbit/s). SONET refers to this basic unit as an STS-3c (Synchronous Transport Signal 3, concatenated). When the STS-3c is carried over OC-3, it is often colloquially referred to as 299:

allows entire inter-country networks to operate synchronously, greatly reducing the amount of buffering required between elements in the network. Both SONET and SDH can be used to

981:

and management software allows the proper filtering and troubleshooting of network-wide performance management, so that defects and outages can be quickly identified and resolved.

360:, but this is not an official designation within the SONET standard as there is no physical layer (i.e. optical) difference between an STS-3c and 3 STS-1s carried within an OC-3. 903: 1139:) can be examined in light of the architectures they will support. Thus, there is value in viewing new, as well as traditional, equipment in terms of the older categories. 1430:

SONET/SDH development was originally driven by the need to transport multiple PDH signals—like DS1, E1, DS3, and E3—along with other groups of multiplexed 64 kbit/s

1465:(LCAS) allows for dynamically changing the bandwidth via dynamic virtual concatenation, multiplexing containers based on the short-term bandwidth needs in the network. 1893: 1126:

To handle all of the possible management channels and signals, most modern network elements contain a router for the network commands and underlying (data) protocols.

952:

Transport of network management data between SDH/ SONET equipment using 'dedicated embedded data communication channels' (DCCs) within the section and line overhead.

1391: 256: 55: 1083:

where the SONET network element is located. This is for local management of that network element and, possibly, remote management of other SONET network elements.

303:

earlier digital transmission standards, such as the PDH standard, or they can be used to directly support either Asynchronous Transfer Mode (ATM) or so-called

1801: 497:

Called regenerator section overhead (RSOH) in SDH terminology: 27 octets containing information about the frame structure required by the terminal equipment.

1781: 1093:

SONET and SDH have dedicated data communication channels (DCCs) within the section and line overhead for management traffic. Generally, section overhead (

1296:

ring. This is why BLSRs are seldom, if ever, deployed in collector rings, but often deployed in inter-office rings. The SDH equivalent of BLSR is called

645:, including dense wavelength-division multiplexing (DWDM) and coarse wavelength-division multiplexing (CWDM). DWDM circuits are the basis for all modern 2335: 2037: 1341: 2275: 1334:

A network element can choose (or be configured) to derive its timing from the line-level, by monitoring the S1 sync-status bytes to ensure quality.

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mode until higher-quality external timing becomes available again. In this mode, the network element uses its own timing circuits as a reference.

949:

Transport of network management data between the 'network management system terminal' and the SONET/ SDH equipment e.g. using TL1/ Q3 protocols.

206:) from a variety of different sources, but they were primarily designed to support real-time, uncompressed, circuit-switched voice encoded in 1974: 1941: 1617: 1310: 874: 296: 272: 260: 218:

Due to SONET/SDH's essential protocol neutrality and transport-oriented features, SONET/SDH was the choice for transporting the fixed length

102: 997:

Local "craftspersons" (telephone network engineers) can access a SDH/ SONET network element on a "craft port" and issue commands through a

946:

Software running on a 'network management system terminal' e.g. workstation, dumb terminal or laptop housed in an exchange/ central office.

74: 2289: 2022: 2147: 1203:

digital traffic. Every SDH/SONET connection on the optical physical layer uses two optical fibers, regardless of the transmission speed.

2375: 2330: 2284: 1508: 1041: 718: 364: 288: 81: 1155:. Also, some of the functionality of regenerators has been absorbed by the transponders of wavelength-division multiplexing systems. 2325: 2320: 2159: 1863: 1761: 1503: 1417: 921: 321: 121: 2336:

ANSI T1.119/ATIS PP 0900119.01.2006: SONET - Operations, Administration, Maintenance, and Provisioning (OAM&P) - Communications

2187: 2033:"Introduction to SONET." Networking - Computer and Wireless Networking Basics - Home Networks Tutorials. Web. 2 December 2011. < 275:(ANSI) standard T1.105. which define the set of transmission formats and transmission rates in the range above 51.840 Mbit/s. 1705: 1682: 1659: 1636: 1258: 642: 300: 284: 180: 88: 1462: 1731: 2385: 1395: 646: 59: 1901: 1837: 1228:. Because the same data is sent around the ring in both directions, the total capacity of a UPSR is equal to the line rate 70: 1163:

STS multiplexer and demultiplexer provide the interface between an electrical tributary network and the optical network.

1191: 1114: 1783:

ANSI T1.105.07-1996 (R2005), Synchronous Optical Network (SONET) – Sub-STS-1 Interface Rates and Formats Specification.

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Black, Uyless D. Emerging Communications Technologies. Englewood Cliffs, NJ: PTR Prentice Hall, 1994. 298-99. Print.

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Network management systems are used to configure and monitor SDH and SONET equipment either locally or remotely.

2351:

ITU-T recommendation G.803: Architecture of Transport Networks Based on the Synchronous Digital Hierarchy (SDH)

1481: 970:

Network-element software upgrades are done mostly through the SONET/SDH management network in modern equipment.

2346:

ITU-T recommendation G.783: Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks

1308:

Clock sources used for synchronization in telecommunications networks are rated by quality, commonly called a

598:

signal. The SDH equivalent of a VTG is a TUG-2; VT1.5 is equivalent to VC-11, and VT2 is equivalent to VC-12.

1022:

This will often consist of software running on a Workstation covering a number of SDH/SONET network elements

1523: 1108: 397: 95: 1458:(GFP) protocols in order to map payloads of arbitrary bandwidth into the virtually concatenated container. 2227: 1684:

ITU-T Rec. G.784, Management aspects of the synchronous digital hierarchy (SDH) transport network element.

1006: 2034: 2272: 1447: 333: 304: 207: 2080: 1707:

ITU-T Rec. G.803, Architecture of transport networks based on the synchronous digital hierarchy (SDH).

1224:

or other failure. UPSRs tend to sit nearer to the edge of a network, and as such are sometimes called

571: 1661:

ITU-T Rec. G.783, Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks.

1513: 1431: 1171: 1136: 363:

SONET offers an additional basic unit of transmission, the STS-1 (Synchronous Transport Signal 1) or

238: 172: 1566:

2,349 octets of payload per frame × 8 bits per octet × 8,000 frames per second = 150.336 Mbit/s

2314: 1609: 658: 558: 393: 389: 168: 2054: 1256:. Any other nodes on the ring could only act as pass-through nodes. The SDH equivalent of UPSR is 179:

data can also be transferred via an electrical interface. The method was developed to replace the

1080: 978: 707: 385: 328: 1468:

The set of next-generation SONET/SDH protocols that enable Ethernet transport is referred to as

550:(SPE), which in turn has 18 stuffing bytes, leading to the STS-1 payload capacity of 756 bytes. 510:

Points to the location of the J1 byte in the payload (the first byte in the virtual container).

2341:

ITU-T recommendation G.707: Network Node Interface for the Synchronous Digital Hierarchy (SDH)

2155: 1970: 1966: 1937: 1613: 1469: 1152: 1120:

Dual (IP+OSI) stack using PPP or LAP-D with tunneling functions to communicate between stacks.

1104: 662: 595: 476:

The STM frame is continuous and is transmitted in a serial fashion: byte-by-byte, row-by-row.

408: 1236:

ring. For example, in an OC-3 ring with 3 STS-1s used to transport 3 DS-3s from ingress node

1958: 1638:

ITU-T Rec. G.707/Y.1322, Network node interface for the synchronous digital hierarchy (SDH).

1601: 1001:

or terminal emulation program running on a laptop. This interface can also be attached to a

674: 587: 336:

for the encapsulated data. Data passing through equipment can be delayed by at most 32

203: 199: 1340:

As a last resort, in the absence of higher quality timing, a network element can go into a

287:(PDH) in that the exact rates that are used to transport the data on SONET/SDH are tightly 2279: 2165: 2041: 1538: 1451: 1065: 562: 400:). In synchronous optical networking, this is modified slightly. The header is termed the 2326:

Telcordia GR-499-CORE, Transport Systems Generic Requirements (TSGR): Common Requirements

1871: 1602: 1557:

2,430 octets per frame × 8 bits per octet × 8,000 frames per second = 155.52 Mbit/s

2331:

ANSI T1.105: SONET - Basic Description including Multiplex Structure, Rates and Formats

2082:

ITU-T Rec. G.7712/Y.1703, Architecture and Specification of Data Communication Network.

1262:(SNCP); SNCP does not impose a ring topology, but may also be used in mesh topologies. 1002: 485: 234: 2359: 2309: 2195: 1959: 1440: 998: 245: 194:

SONET and SDH, which are essentially the same, were originally designed to transport

160: 2304: 1079:, sends SONET TL1 commands from a local management network physically housed in the 1739: 1325: 1010: 602: 292: 195: 150: 1369: 614: 455: 417: 413: 337: 156: 37: 1965:. Artech House space applications series (3rd ed.). Artech House. p. 1766:

Synchronous Optical Network (SONET) Transport Systems: Common Generic Criteria

153: 1990: 942:

The systems consist of three essential parts, covered later in more detail:

554: 465:

The section overhead (SOH) of a STM-1 signal is divided into two parts: the

436: 268: 212: 184: 2055:"Framework for the Integrated Management of Hybrid Circuit/Packet Networks" 1932:

Tozer, Edwin Paul J. (2004). "1.8.11 Synchronous Digital Hierarchy (SDH)".

681:

signals, which can normally support thin-SONET–framed 10 Gigabit Ethernet.

392:. The header is transmitted first, followed by the payload (and possibly a 2148:"Chapter 5: Timing, Clocking, and Synchronization in the T-carrier System" 2243: 1533: 381: 223: 176: 484:

The transport overhead is used for signaling and measuring transmission

2321:

Telcordia GR-253-CORE, SONET Transport Systems: Common Generic Criteria

1786:, New York: American National Standards Institute, 1996, archived from 1076: 637: 540:

User data (774 bytes for STM-0/STS-1, or 2,430 octets for STM-1/STS-3c)

2350: 2345: 2340: 2035:

http://compnetworking.about.com/od/hardwarenetworkgear/l/aa092800a.htm

2021:"SONET: How Does SONET Work?" Capybara.Org. Web. 2 December 2011. < 229: 17: 832: 813: 633: 353: 249: 191:

traffic over the same fiber without the problems of synchronization.

2267: 2121: 2096: 669:) with a line rate of 10.3125 Gbit/s, and a wide area variant ( 352:(Synchronous Transport Module, level 1), which operates at 155.520 1528: 1098: 1045: 794: 775: 756: 626: 622: 583: 444: 435: 349: 264: 228: 164: 2188:"Why is a timing loop so bad, and why is it so difficult to fix?" 1151:

Since the late 1990s, regenerators have been largely replaced by

737: 665:

created two 10 Gigabit Ethernet variants: a local area variant (

610: 445: 368: 357: 188: 1575:

line rate minus the bandwidth of the line and section overheads

2085:, Geneva: International Telecommunication Union, 30 March 2007 1363: 1049: 1036: 878: 591: 31: 1641:, Geneva: International Telecommunication Union, January 2007 534:

9 octets used for end-to-end signaling and error measurement.

1870:. International Engineering Consortium. 2007. Archived from 1317:

Synchronization sources available to a network element are:

1844:. San Jose, California: Cisco indiA Systems. 1 October 2006 1710:, Geneva: International Telecommunication Union, March 2000 1687:, Geneva: International Telecommunication Union, March 2008 1664:, Geneva: International Telecommunication Union, March 2006 1211:

Linear Automatic Protection Switching (APS), also known as

956:

The main functions of network management thereby include:

327:

The protocol is a heavily multiplexed structure, with the

2294: 1838:"Synchronous Digital Hierarchy (SDH) Graphical Overview" 1068:

have a limited number of management interfaces defined:

899: 244:

Both SDH and SONET are widely used today: SONET in the

1178:(where the full line rate signal is supported), and a 657:

Another type of high-speed data networking circuit is

267:, G.784, and G.803. The SONET standard was defined by 1088:

Dedicated embedded data communication channels (DCCs)

1018:

Network management system (sitting at a higher layer)

1989:

Tyson, Jeff. "How OSI Works" HowStuffWorks.com. <

149:) are standardized protocols that transfer multiple 1900:. Global Communications Group. 2009. Archived from 1604:

Telecommunications and Data Communications Handbook

1101:G.7712, there are three modes used for management: 894:

may be too technical for most readers to understand

609:to form the next level of the SONET hierarchy, the 590:signal. A VTG may instead be subdivided into three 578:An STS-1 payload can also be subdivided into seven 521:Data transmitted from end to end is referred to as 62:. Unsourced material may be challenged and removed. 2273:The Queen's University of Belfast SDH/SONET Primer 582:(VTGs). Each VTG can then be subdivided into four 553:The STS-1 payload is designed to carry a full PDH 653:SONET/SDH and relationship to 10 Gigabit Ethernet 257:European Telecommunications Standards Institute 255:The SDH standard was originally defined by the 183:(PDH) system for transporting large amounts of 1802:"Forward error correction in optical networks" 856:deployed; most are considered orphaned rates. 380:In packet-oriented data transmission, such as 1776: 1774: 546:For STS-1, the payload is referred to as the 8: 2310:Next-generation SDH: the future looks bright 557:frame. When the DS3 enters a SONET network, 1398:. Unsourced material may be challenged and 2192:Optical Timing: Frequently Asked Questions 1726: 1724: 1035:SONET equipment is often managed with the 632:The highest rate commonly deployed is the 407:In the case of an STS-1, the frame is 810 1991:http://computer.howstuffworks.com/osi.htm 1595: 1593: 1591: 1418:Learn how and when to remove this message 922:Learn how and when to remove this message 906:, without removing the technical details. 122:Learn how and when to remove this message 1298:Multiplex Section-Shared Protection Ring 985:Consider the three parts defined above: 960:Network and network-element provisioning 688: 2290:SONET Pocket Handbook from Acterna/JDSU 1961:Introduction to Satellite Communication 1631: 1629: 1587: 1550: 594:signals, each of which can carry a PDH 586:signals, each of which can carry a PDH 384:, a packet frame usually consists of a 1283:ring, and can actually be larger than 869:SONET/SDH network management protocols 649:systems and other long-haul circuits. 348:The basic unit of framing in SDH is a 324:in the way that term is usually used. 2285:SDH Pocket Handbook from Acterna/JDSU 1864:"Synchronous Optical Network (SONET)" 1244:, 100 percent of the ring bandwidth ( 1207:Linear Automatic Protection Switching 1117:-only stack, using LAP-D as data-link 904:make it understandable to non-experts 875:Telecommunications Management Network 691:SONET/SDH Designations and bandwidths 273:American National Standards Institute 261:International Telecommunication Union 7: 1738:. TechFest.com. 2002. Archived from 1396:adding citations to reliable sources 1137:multi-service provisioning platforms 525:. It is composed of two components: 60:adding citations to reliable sources 2305:Network Connection Speeds Reference 1934:Broadcast Engineer's Reference Book 1509:Multiwavelength optical networking 1075:The electrical interface, often a 989:Network management system terminal 25: 2300:SONET Interoperability Form (SIF) 1504:Routing and wavelength assignment 1219:Unidirectional path-switched ring 1159:STS multiplexer and demultiplexer 291:across the entire network, using 1368: 1266:Bidirectional line-switched ring 1259:subnetwork connection protection 883: 643:wavelength-division multiplexing 507:Administrative unit (AU) pointer 285:Plesiochronous Digital Hierarchy 181:plesiochronous digital hierarchy 71:"Synchronous optical networking" 36: 1463:Link Capacity Adjustment Scheme 1248:=3) would be consumed by nodes 47:needs additional citations for 2371:ITU-T G Series Recommendations 2366:Synchronous optical networking 1608:. Wiley-Interscience. p. 1097:in SDH) is used. According to 647:submarine communications cable 488:, and is composed as follows: 135:Synchronous Optical Networking 1: 1732:"SONET/SDH Technical Summary" 1192:digital cross connect systems 567:path generator and terminator 259:(ETSI), and is formalised as 143:Synchronous Digital Hierarchy 2146:Matthew Gast (August 2001). 1894:"OC 768 Internet Connection" 1186:Digital cross connect system 697:SONET Optical Carrier level 548:synchronous payload envelope 467:regenerator section overhead 2122:"Understanding SONET BLSRs" 2097:"Understanding SONET UPSRs" 1936:. Focal Press. p. 97. 845: 842: 826: 823: 807: 804: 788: 785: 769: 766: 750: 747: 731: 728: 703:SDH level and frame format 601:Three STS-1 signals may be 2402: 2376:Fiber-optic communications 2154:. "O'Reilly Media, Inc.". 1476:End of life and retirement 872: 607:time-division multiplexing 471:multiplex section overhead 220:Asynchronous Transfer Mode 2278:20 September 2005 at the 1957:Elbert, Bruce R. (2008). 1519:Optical Transport Network 1499:List of device bandwidths 1482:internet access providers 1456:Generic Framing Procedure 1360:Next-generation SONET/SDH 561:is added, and that SONET 1768:(October 2009). Issue 5. 1324:This is generated by an 1072:TL1 Electrical interface 580:virtual tributary groups 2315:The Future of SONET/SDH 2268:Understanding SONET/SDH 2240:"MegaStream Withdrawal" 1524:Remote error indication 1470:Ethernet over SONET/SDH 344:Basic transmission unit 263:(ITU) standards G.707, 1480:SONET/SDH was used by 1007:out-of-band management 1005:, allowing for remote 973:Performance management 531:Payload overhead (POH) 451: 442: 297:synchronization system 241: 198:communications (e.g., 2386:ITU-T recommendations 2217:KiloStream Retirement 1993:> 2 December 2011. 1922:IEEE Std 802.3bv-2017 1809:Conexant Systems, Inc 1448:Virtual concatenation 1435:data-oriented pipes. 1321:Local external timing 1198:Network architectures 1172:Add-drop multiplexers 994:Local Craft interface 935:Overall functionality 661:(10GbE). The Gigabit 565:(NE) is said to be a 517:Path virtual envelope 448: 439: 305:packet over SONET/SDH 239:add-drop multiplexers 232: 173:light-emitting diodes 27:Standardized protocol 2228:SDH to OTN Migration 2152:T1: A Survival Guide 2040:20 June 2016 at the 1904:on 20 September 2010 1514:Optical mesh network 1432:pulse-code modulated 1392:improve this section 1167:Add-drop multiplexer 1077:50-ohm coaxial cable 685:SONET/SDH data rates 56:improve this article 1818:on 10 December 2014 1600:Horak, Ray (2007). 1331:Line-derived timing 1326:atomic cesium clock 1240:to the egress node 1148:high-power signal. 1107:-only stack, using 1095:regenerator section 964:management network. 713:Line rate (kbit/s) 706:Payload bandwidth ( 700:SONET frame format 693: 659:10 Gigabit Ethernet 354:megabits per second 322:connection-oriented 279:Difference from PDH 2295:The Sonet Homepage 1742:on 27 January 1999 1153:optical amplifiers 979:network monitoring 689: 569:. The SONET NE is 480:Transport overhead 452: 450:contains pointers. 443: 242: 177:transmission rates 2381:Network protocols 2198:. 2 December 2005 2168:on 18 August 2001 1976:978-1-59693-210-4 1943:978-0-240-51908-1 1619:978-0-470-04141-3 1428: 1427: 1420: 1026:TL1/ Q3 Protocols 932: 931: 924: 850: 849: 663:Ethernet Alliance 424:given bandwidth. 311:Protocol overview 283:SDH differs from 132: 131: 124: 106: 16:(Redirected from 2393: 2256: 2255: 2253: 2251: 2242:. Archived from 2236: 2230: 2225: 2219: 2214: 2208: 2207: 2205: 2203: 2184: 2178: 2177: 2175: 2173: 2164:. Archived from 2143: 2137: 2136: 2134: 2132: 2118: 2112: 2111: 2109: 2107: 2093: 2087: 2086: 2077: 2071: 2070: 2068: 2066: 2051: 2045: 2031: 2025: 2019: 2013: 2009: 2003: 2000: 1994: 1987: 1981: 1980: 1964: 1954: 1948: 1947: 1929: 1923: 1920: 1914: 1913: 1911: 1909: 1890: 1884: 1883: 1881: 1879: 1860: 1854: 1853: 1851: 1849: 1834: 1828: 1827: 1825: 1823: 1817: 1811:. Archived from 1806: 1798: 1792: 1791: 1778: 1769: 1758: 1752: 1751: 1749: 1747: 1728: 1719: 1718: 1717: 1715: 1702: 1696: 1695: 1694: 1692: 1679: 1673: 1672: 1671: 1669: 1656: 1650: 1649: 1648: 1646: 1633: 1624: 1623: 1607: 1597: 1576: 1573: 1567: 1564: 1558: 1555: 1423: 1416: 1412: 1409: 1403: 1372: 1364: 967:Software upgrade 927: 920: 916: 913: 907: 887: 886: 879: 694: 572:line terminating 494:Section overhead 127: 120: 116: 113: 107: 105: 64: 40: 32: 21: 2401: 2400: 2396: 2395: 2394: 2392: 2391: 2390: 2356: 2355: 2280:Wayback Machine 2264: 2259: 2249: 2247: 2238: 2237: 2233: 2226: 2222: 2215: 2211: 2201: 2199: 2186: 2185: 2181: 2171: 2169: 2162: 2145: 2144: 2140: 2130: 2128: 2120: 2119: 2115: 2105: 2103: 2095: 2094: 2090: 2079: 2078: 2074: 2064: 2062: 2053: 2052: 2048: 2042:Wayback Machine 2032: 2028: 2020: 2016: 2010: 2006: 2001: 1997: 1988: 1984: 1977: 1956: 1955: 1951: 1944: 1931: 1930: 1926: 1921: 1917: 1907: 1905: 1892: 1891: 1887: 1877: 1875: 1874:on 7 April 2008 1862: 1861: 1857: 1847: 1845: 1836: 1835: 1831: 1821: 1819: 1815: 1804: 1800: 1799: 1795: 1790:on 6 March 2012 1780: 1779: 1772: 1759: 1755: 1745: 1743: 1730: 1729: 1722: 1713: 1711: 1704: 1703: 1699: 1690: 1688: 1681: 1680: 1676: 1667: 1665: 1658: 1657: 1653: 1644: 1642: 1635: 1634: 1627: 1620: 1599: 1598: 1589: 1585: 1580: 1579: 1574: 1570: 1565: 1561: 1556: 1552: 1547: 1539:Internet access 1495: 1478: 1424: 1413: 1407: 1404: 1389: 1373: 1362: 1353: 1306: 1304:Synchronization 1268: 1226:collector rings 1221: 1209: 1200: 1188: 1176:high-speed side 1169: 1161: 1145: 1132: 1090: 1028: 991: 937: 928: 917: 911: 908: 900:help improve it 897: 888: 884: 877: 871: 862: 687: 655: 563:network element 519: 482: 469:(RSOH) and the 434: 378: 346: 313: 281: 175:(LEDs). At low 128: 117: 111: 108: 65: 63: 53: 41: 28: 23: 22: 15: 12: 11: 5: 2399: 2397: 2389: 2388: 2383: 2378: 2373: 2368: 2358: 2357: 2354: 2353: 2348: 2343: 2338: 2333: 2328: 2323: 2318: 2312: 2307: 2302: 2297: 2292: 2287: 2282: 2270: 2263: 2262:External links 2260: 2258: 2257: 2246:on 5 July 2020 2231: 2220: 2209: 2179: 2160: 2138: 2126:SONET Homepage 2113: 2101:SONET Homepage 2088: 2072: 2046: 2026: 2014: 2004: 1995: 1982: 1975: 1949: 1942: 1924: 1915: 1885: 1855: 1829: 1793: 1770: 1753: 1720: 1697: 1674: 1651: 1625: 1618: 1586: 1584: 1581: 1578: 1577: 1568: 1559: 1549: 1548: 1546: 1543: 1542: 1541: 1536: 1531: 1526: 1521: 1516: 1511: 1506: 1501: 1494: 1491: 1477: 1474: 1426: 1425: 1376: 1374: 1367: 1361: 1358: 1352: 1349: 1348: 1347: 1338: 1335: 1332: 1329: 1322: 1305: 1302: 1267: 1264: 1220: 1217: 1208: 1205: 1199: 1196: 1187: 1184: 1180:low-speed side 1168: 1165: 1160: 1157: 1144: 1141: 1131: 1128: 1124: 1123: 1122: 1121: 1118: 1112: 1089: 1086: 1085: 1084: 1081:central office 1073: 1058: 1057: 1033: 1032: 1027: 1024: 1020: 1019: 1015: 1014: 1003:console server 995: 990: 987: 983: 982: 974: 971: 968: 965: 961: 954: 953: 950: 947: 936: 933: 930: 929: 891: 889: 882: 870: 867: 861: 860:Physical layer 858: 848: 847: 844: 841: 838: 835: 829: 828: 825: 822: 819: 816: 810: 809: 806: 803: 800: 797: 791: 790: 787: 784: 781: 778: 772: 771: 768: 765: 762: 759: 753: 752: 749: 746: 743: 740: 734: 733: 730: 727: 724: 721: 715: 714: 711: 704: 701: 698: 686: 683: 654: 651: 544: 543: 542: 541: 538: 535: 532: 518: 515: 514: 513: 512: 511: 508: 505: 501: 498: 495: 481: 478: 433: 430: 377: 374: 345: 342: 312: 309: 280: 277: 130: 129: 44: 42: 35: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 2398: 2387: 2384: 2382: 2379: 2377: 2374: 2372: 2369: 2367: 2364: 2363: 2361: 2352: 2349: 2347: 2344: 2342: 2339: 2337: 2334: 2332: 2329: 2327: 2324: 2322: 2319: 2316: 2313: 2311: 2308: 2306: 2303: 2301: 2298: 2296: 2293: 2291: 2288: 2286: 2283: 2281: 2277: 2274: 2271: 2269: 2266: 2265: 2261: 2245: 2241: 2235: 2232: 2229: 2224: 2221: 2218: 2213: 2210: 2197: 2196:Cisco Systems 2193: 2189: 2183: 2180: 2167: 2163: 2161:0-596-00127-4 2157: 2153: 2149: 2142: 2139: 2127: 2123: 2117: 2114: 2102: 2098: 2092: 2089: 2084: 2083: 2076: 2073: 2060: 2056: 2050: 2047: 2043: 2039: 2036: 2030: 2027: 2023: 2018: 2015: 2008: 2005: 1999: 1996: 1992: 1986: 1983: 1978: 1972: 1968: 1963: 1962: 1953: 1950: 1945: 1939: 1935: 1928: 1925: 1919: 1916: 1903: 1899: 1895: 1889: 1886: 1873: 1869: 1868:Web ProForums 1865: 1859: 1856: 1843: 1839: 1833: 1830: 1814: 1810: 1803: 1797: 1794: 1789: 1785: 1784: 1777: 1775: 1771: 1767: 1763: 1757: 1754: 1741: 1737: 1733: 1727: 1725: 1721: 1709: 1708: 1701: 1698: 1686: 1685: 1678: 1675: 1663: 1662: 1655: 1652: 1640: 1639: 1632: 1630: 1626: 1621: 1615: 1611: 1606: 1605: 1596: 1594: 1592: 1588: 1582: 1572: 1569: 1563: 1560: 1554: 1551: 1544: 1540: 1537: 1535: 1532: 1530: 1527: 1525: 1522: 1520: 1517: 1515: 1512: 1510: 1507: 1505: 1502: 1500: 1497: 1496: 1492: 1490: 1486: 1483: 1475: 1473: 1471: 1466: 1464: 1459: 1457: 1453: 1449: 1445: 1442: 1441:Fast Ethernet 1436: 1433: 1422: 1419: 1411: 1408:November 2010 1401: 1397: 1393: 1387: 1386: 1382: 1377:This section 1375: 1371: 1366: 1365: 1359: 1357: 1350: 1345: 1344: 1339: 1336: 1333: 1330: 1327: 1323: 1320: 1319: 1318: 1315: 1313: 1312: 1303: 1301: 1300:(MS-SPRING). 1299: 1295: 1291: 1286: 1282: 1278: 1272: 1265: 1263: 1261: 1260: 1255: 1251: 1247: 1243: 1239: 1235: 1231: 1227: 1218: 1216: 1214: 1206: 1204: 1197: 1195: 1193: 1185: 1183: 1181: 1177: 1173: 1166: 1164: 1158: 1156: 1154: 1149: 1142: 1140: 1138: 1129: 1127: 1119: 1116: 1113: 1110: 1106: 1103: 1102: 1100: 1096: 1092: 1091: 1087: 1082: 1078: 1074: 1071: 1070: 1069: 1067: 1062: 1055: 1054: 1053: 1051: 1047: 1043: 1038: 1030: 1029: 1025: 1023: 1017: 1016: 1012: 1008: 1004: 1000: 999:dumb terminal 996: 993: 992: 988: 986: 980: 975: 972: 969: 966: 962: 959: 958: 957: 951: 948: 945: 944: 943: 940: 934: 926: 923: 915: 912:November 2010 905: 901: 895: 892:This section 890: 881: 880: 876: 868: 866: 859: 857: 853: 839: 836: 834: 831: 830: 820: 817: 815: 812: 811: 801: 798: 796: 793: 792: 782: 779: 777: 774: 773: 763: 760: 758: 755: 754: 744: 741: 739: 736: 735: 725: 722: 720: 717: 716: 712: 709: 705: 702: 699: 696: 695: 692: 684: 682: 678: 677:line coding. 676: 672: 668: 664: 660: 652: 650: 648: 644: 639: 635: 630: 628: 624: 618: 616: 612: 608: 604: 599: 597: 593: 589: 585: 581: 576: 574: 573: 568: 564: 560: 559:path overhead 556: 551: 549: 539: 536: 533: 530: 529: 528: 527: 526: 524: 516: 509: 506: 502: 500:Line overhead 499: 496: 493: 492: 491: 490: 489: 487: 479: 477: 474: 472: 468: 463: 459: 457: 447: 438: 431: 429: 425: 421: 419: 415: 410: 405: 403: 399: 395: 391: 387: 383: 375: 373: 370: 366: 361: 359: 355: 351: 343: 341: 339: 335: 330: 325: 323: 317: 310: 308: 306: 302: 298: 294: 293:atomic clocks 290: 286: 278: 276: 274: 270: 266: 262: 258: 253: 251: 247: 246:United States 240: 236: 231: 227: 225: 221: 216: 214: 209: 205: 201: 197: 192: 190: 186: 182: 178: 174: 170: 166: 162: 161:optical fiber 158: 157:synchronously 155: 152: 148: 144: 140: 136: 126: 123: 115: 104: 101: 97: 94: 90: 87: 83: 80: 76: 73: – 72: 68: 67:Find sources: 61: 57: 51: 50: 45:This article 43: 39: 34: 33: 30: 19: 2248:. Retrieved 2244:the original 2234: 2223: 2212: 2202:28 September 2200:. Retrieved 2191: 2182: 2172:28 September 2170:. Retrieved 2166:the original 2151: 2141: 2129:. Retrieved 2125: 2116: 2104:. Retrieved 2100: 2091: 2081: 2075: 2063:. Retrieved 2059:www.ietf.org 2058: 2049: 2029: 2017: 2007: 1998: 1985: 1960: 1952: 1933: 1927: 1918: 1906:. Retrieved 1902:the original 1897: 1888: 1876:. Retrieved 1872:the original 1867: 1858: 1846:. Retrieved 1841: 1832: 1820:. Retrieved 1813:the original 1808: 1796: 1788:the original 1782: 1765: 1756: 1744:. Retrieved 1740:the original 1735: 1712:, retrieved 1706: 1700: 1689:, retrieved 1683: 1677: 1666:, retrieved 1660: 1654: 1643:, retrieved 1637: 1603: 1571: 1562: 1553: 1487: 1479: 1467: 1460: 1446: 1437: 1429: 1414: 1405: 1390:Please help 1378: 1354: 1351:Timing loops 1342: 1316: 1309: 1307: 1297: 1293: 1289: 1284: 1280: 1276: 1273: 1269: 1257: 1253: 1249: 1245: 1241: 1237: 1233: 1229: 1225: 1222: 1212: 1210: 1201: 1189: 1179: 1175: 1170: 1162: 1150: 1146: 1133: 1125: 1111:as data-link 1094: 1063: 1059: 1034: 1021: 984: 955: 941: 938: 918: 909: 893: 863: 854: 851: 690: 679: 670: 666: 656: 631: 619: 600: 579: 577: 570: 566: 552: 545: 522: 520: 483: 475: 470: 466: 464: 460: 453: 426: 422: 406: 401: 396:, such as a 379: 362: 347: 338:microseconds 326: 318: 314: 289:synchronized 282: 254: 243: 217: 196:circuit mode 193: 146: 142: 138: 134: 133: 118: 109: 99: 92: 85: 78: 66: 54:Please help 49:verification 46: 29: 2131:14 November 2106:14 November 1908:14 November 1848:14 November 1822:10 December 1762:GR-253-CORE 1746:13 November 1143:Regenerator 1064:Most SONET 846:39,813,120 843:38,486,016 603:multiplexed 486:error rates 301:encapsulate 237:STM-16 SDH 171:light from 154:bit streams 2360:Categories 1760:Telcordia 1714:3 November 1691:3 November 1668:3 November 1645:3 November 1583:References 1292:of the OC- 1288:line rate 1279:of the OC- 1232:of the OC- 873:See also: 827:9,953,280 824:9,621,504 808:2,488,320 805:2,405,376 789:1,244,160 786:1,202,688 187:calls and 167:or highly 82:newspapers 1379:does not 1130:Equipment 523:path data 432:SDH frame 412:125 269:Telcordia 233:Racks of 213:OSI Model 185:telephone 112:July 2007 2276:Archived 2038:Archived 1878:21 April 1736:TechFest 1534:Transmux 1493:See also 1343:holdover 1337:Holdover 840:STM-256 837:STS-768 818:STS-192 770:622,080 767:601,344 751:155,520 748:150,336 402:overhead 382:Ethernet 224:Ethernet 215:sense). 169:coherent 2065:15 June 1472:(EoS). 1400:removed 1385:sources 1311:stratum 1190:Recent 1011:logging 898:Please 821:STM-64 802:STM-16 799:STS-48 780:STS-24 761:STS-12 732:51,840 729:50,112 675:64B/66B 671:WAN PHY 667:LAN PHY 638:STM-256 537:Payload 394:trailer 390:payload 376:Framing 334:latency 295:. This 235:Alcatel 151:digital 96:scholar 2250:4 July 2158: 2061:. 2003 2012:Print. 1973: 1940: 1616: 833:OC-768 814:OC-192 764:STM-4 745:STM-1 742:STS-3 726:STM-0 723:STS-1 708:kbit/s 634:OC-768 504:above. 441:order. 409:octets 388:and a 386:header 329:header 250:Canada 165:lasers 163:using 141:) and 98: 91: 84: 77: 69: 18:STM-16 2317:(pdf) 2044:>. 2024:>. 1842:Cisco 1816:(PDF) 1805:(PDF) 1545:Notes 1529:G.709 1099:ITU-T 1048:, or 1046:CORBA 795:OC-48 776:OC-24 757:OC-12 627:STM-4 623:OC-12 584:VT1.5 358:OC-3c 350:STM-1 265:G.783 159:over 139:SONET 103:JSTOR 89:books 2252:2020 2204:2012 2174:2012 2156:ISBN 2133:2010 2108:2010 2067:2023 1971:ISBN 1938:ISBN 1910:2010 1880:2007 1850:2010 1824:2014 1748:2010 1716:2010 1693:2010 1670:2010 1647:2010 1614:ISBN 1461:The 1452:X.86 1383:any 1381:cite 1252:and 1042:SNMP 1009:and 738:OC-3 719:OC-1 611:OC-3 369:DS-3 365:OC-1 271:and 248:and 189:data 75:news 1898:GCG 1610:476 1454:or 1394:by 1213:1+1 1115:OSI 1109:PPP 1066:NEs 1050:XML 1037:TL1 1031:TL1 902:to 636:or 625:or 605:by 592:VT2 588:DS1 555:DS3 398:CRC 208:PCM 204:DS3 200:DS1 147:SDH 58:by 2362:: 2194:. 2190:. 2150:. 2124:. 2099:. 2057:. 1969:. 1967:73 1896:. 1866:. 1840:. 1807:. 1773:^ 1764:, 1734:. 1723:^ 1628:^ 1612:. 1590:^ 1105:IP 1056:Q3 1052:. 1044:, 783:– 710:) 629:. 617:. 615:μs 596:E1 456:μs 418:μs 414:μs 202:, 2254:. 2206:. 2176:. 2135:. 2110:. 2069:. 1979:. 1946:. 1912:. 1882:. 1852:. 1826:. 1750:. 1622:. 1421:) 1415:( 1410:) 1406:( 1402:. 1388:. 1294:N 1290:N 1285:N 1281:N 1277:N 1254:D 1250:A 1246:N 1242:D 1238:A 1234:N 1230:N 1013:. 925:) 919:( 914:) 910:( 896:. 145:( 137:( 125:) 119:( 114:) 110:( 100:· 93:· 86:· 79:· 52:. 20:)

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Knowledge (XXG)

Synchronous optical networking

Index