Lecture 12

Lecture 12 - EE 555 Broadband Network Architectures Network...

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EE 555 Broadband Network Architectures Link Layer (layers 1.5 and 2) Prof. John Silvester Traditional Digital Hierarchy (Asynchronous or Plesiosynchronous) • Based on multiplexing of digital voice at 64 Based on multiplexing of digital voice at 64 Kbps Each node runs its own clock leads to • Each node runs its own clock – leads to differences in rates requiring bit stuffing to align frames (higher level signals have align frames (higher level signals have additional bits for this) • Difficult to pick out individual streams without demuxing all levels usc-den-ee555-silvester-spring2009 2
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Plesiosynchronous Hierarchy Level N. America Europe 0 64 Kbps 64 Kbps 1 1.544 Mbps 2.048 Mbps 2 6 312 Mbp 8 448 Mbps 6.312 Mbps 8.448 Mbps 3 44.736 Mbps 34.368 Mbps 4 139.264 Mbps 139.264 Mbps usc-den-ee555-silvester-spring2009 3 SONET and SDH SONET Synchronous Optical Network • SONET – Synchronous Optical Network (US) • SDH – Synchronous Digital Hierarchy (Europe, Japan, most submarine cable) • Based on a standard reference synchronized clock – much easier to pull out individual streams
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SONET SONET and SDH (Synchronous Digital Hierarchy) Layer 1.5 transport mechanism Implements timing, framing and multiplexing structure for TDM along with path and link management and control functionality Basic Rate is Synchronous Transport Level-1 (STS-1) is 51.84 (electrical signal; usually output is optical signal OC-x) which may be scrambled to reduce long 0 or 1 runs) For SDH the basic rate is 155 Mbps and is called STM 1 For SDH the basic rate is 155 Mbps and is called STM-1 (Synchronous Transport Module – 1) Higher rates STS-n from byte interleaving the streams STS nc indicates “concatenated” meaning that the signals cannot be STS-nc indicates concatenated meaning that the signals cannot be split down in to component streams – it is a single stream (consequently does not need independent overhead columns for each possible STS-1 subchannel) usc-den-ee555-silvester-spring2009 5 SONET Optical Carrier Line Rates Optical Level SDH Line Rate (Mbps Payload Rate (Mbps O/H Rate (Mbps Equivalent (Mbps) (Mbps) (Mbps) OC-1 none 51.840 50.112 1.728 OC-3 STM-1 155.520 150.336 5.184 OC-9 (STM-3) 466.560 451.008 15.552 OC-12 STM-4 622.080 601.344 20.736 OC-18 (STM-6) 933.120 902.016 31.104 OC-24 (STM-8) 1244.160 1202.688 41.472 OC-36 (STM-13) 1866.240 1804.032 62.208 OC-48 STM-16 2488.320 2405.376 82.944 OC-96 (STM-32) 4976.640 4810.752 165.888 OC-192 STM-64 9953.280 9621.504 331.776 OC-768 STM-256 39814.32 38486.016 1327.104 usc-den-ee555-silvester-spring2009 6-6
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SONET Frame Structure Note frame duration is 125 μ s – 8K samples per second (voice) usc-den-ee555-silvester-spring2009 6-7 SONET Overhead Payload pointer Term regen ADM Term section line path usc-den-ee555-silvester-spring2009 6-8
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SONET Payload Envelope usc-den-ee555-silvester-spring2009 6-9 SONET- OC-3vsOC-3 SONET OC 3 vs OC 3c Note: byte interleaved by a factor of 3 since OC-3 usc-den-ee555-silvester-spring2009 6-10 Note: byte interleaved by a factor of 3 since OC 3 10
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SONET Infrastructure usc-den-ee555-silvester-spring2009 11 Additions to SONET/SDH for Data
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This note was uploaded on 12/22/2010 for the course EE 555 taught by Professor Silvester during the Fall '08 term at USC.

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Lecture 12 - EE 555 Broadband Network Architectures Network...

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