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SONET OAM&P Interexchange Carrier Network Provider FOTS FOTS FOTS DS-3 Mux Proprietary Keep Alive Signal AIS (blue signal) Limited Surveillance in Existing Asynchronous System Interexchange Carrier Network Provider 40 SONET Terminal A SONET Hub SONET Hub SONET Terminal DS-3 AIS Detects Failure at Hub STS Path AIS STS Path—Yellow Alarm Line FERF SONET offers improved surveillance with extra alerting indications. Even site A is aware of the problem downstream. Figure 4-2 • Improved Surveillance AIS: Alarm Indication Signal FERF: Far End Receive Fail Signal
SONET OAM&P ENHANCED PERFORMANCE MONITORING SONET overhead is organized into three layers defined as section, line, and path overhead. They provide abundant information for alarm surveillance and performance monitoring. Many bytes in the SONET overhead are allocated for Bit Interleave Parity-8 (BIP-8), a method of error monitoring. This BIP-8 is actually a byte (eight bits) which creates an even parity over a sequence of bits in the transmitting signal. A full set of performance monitoring statistics can be generated with the format, helping to locate degraded conditions before they become serious. BIP-8 allows for sectionalization of alarms and single-ended maintenance. Performance information is available for all levels down to the VT path levels, which means parity error information is available for DS-1s on an end-to-end basis. At the VT level, performance monitoring is accomplished by a BIP-2. Present FOTS systems provide parity error information only for line rate and DS-3 rate. An example of improved facility maintenance and surveillance appears at the bottom of Figure 4-2. In case of a failure indicated by an X in the diagram, an alarm indication signal (AIS) is sent to suppress downstream alarms. The terminal upstream at the left side (A) may be unaware that a failure has occurred. SONET provides extra information such as a yellow alarm indication signal at the path level from the far end terminal to site A. In addition, a far-end receive failure (FERF) signal at the line layer overhead is sent from the hub detecting the failure to tell site A that a failure has occurred downstream. 41 With SONET’s enhanced performance monitoring and surveillance, the time it takes to restore service is reduced. Also, fewer maintenance actions are required since faults can be more easily sectionalized. Added to this are the advantages of SONET’s built-in data communications networking. SONET <strong>101</strong>
Page 1: HDSL About • IXC • BISDN • CC
Page 4 and 5: What is SONET? Figure 1-1 • SONET
Page 6 and 7: What is SONET? STS-1 51.84 Mbps STS
Page 8 and 9: What is SONET? Figure 1-3 • ISDN
Page 10 and 11: What is SONET? Transport Overhead S
Page 12 and 13: What is SONET? Path Terminating Equ
Page 14 and 15: What is SONET? VT payloads and VT p
Page 16 and 17: What is SONET? STS Path Overhead Fi
Page 18 and 19: What is SONET? Frame 1 STS-1 Pointe
Page 20 and 21: What is SONET? SONET NETWORK ELEMEN
Page 22 and 23: What is SONET? Broadband Digital Cr
Page 24 and 25: Why Synchronize? SYNCHRONIZATION HI
Page 26 and 27: Why Synchronize? External Reference
Page 28 and 29: What are the Benefits of SONET? Nod
Page 30 and 31: What are the Benefits of SONET? GRO
Page 32 and 33: What are the Benefits of SONET? DSX
Page 34 and 35: What are the Benefits of SONET? NEW
Page 36 and 37: What are the Benefits of SONET? OPT
Page 38 and 39: SONET OAM&P FOTS A FOTS DSX or Digi
Page 42 and 43: SONET OAM&P TELECOMMUNICATIONS MANA
Page 45 and 46: 5 HDSL SONET • IXC • BISDN •
Page 47 and 48: SONET Networking Switching Node DSX
Page 49 and 50: SONET Networking Enhanced Survivabi
Page 51 and 52: SONET Networking Local Inter-Node D
Page 53 and 54: SONET Networking OC-n OC-n City A C
Page 55 and 56: SONET Networking HUB — Switching
Page 57: SONET Networking Hub Application Un
Page 60 and 61: Synchronous Digital Hierarchy Conve
Page 62 and 63: Contributions to SONET Working in c
Page 64 and 65: List of Terms CEPT—European Confe
Page 66 and 67: List of Terms Packet Switching—An

sonet 101

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