SONETSDH Introduction What is the Difference Between SONET

Why SDH/SONET? • SDH (Synchronous Digital Hierarchy) and SONET (Synchronous Optical NETwork) are standards for interfacing optical networks. • Simple multiplexing processes • Easy access to various signals in a multiplexed high bit rate signal • A flexible and efficient way of networking – Network Distribution: Add/Drop capability – Network survivability: APS (Automatic Protection Switching) – Traffic Cross connection: capacity management, bandwidth management and protection route diversity • Support advance Network Management System (OAM&P) – Overhead bits for Fault, Configuration, Performance Monitoring, Security and Accounting management • Standardized interface can support multi vendor interworking, international connection and many different services; i. e. ATM, IP R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 2

SONET/SDH Digital Hierarchy Optical Level SONET Electrical Level SDH Equivalent Line Rate (Mbps) Payload Rate (Mbps) Overhead Rate (Mbps) SONET Capacity SDH Capacity OC-1 STS-1 – 51. 840 50. 112 1. 728 28 DS-1 s or 1 DS-3 21 E 1 s OC-3 STS-3 STM-1 155. 520 150. 336 5. 184 84 DS-1 s or 3 DS-3 s 63 E 1 s or 1 E 4 OC-12 STS-12 STM-4 622. 080 601. 344 20. 736 336 DS-1 s or 12 DS-3 s 252 E 1 s or 4 E 4 s OC-48 STS-48 STM-16 2488. 320 2405. 376 82. 944 1, 344 DS-1 s or 192 DS-3 s 1, 008 E 1 s or 16 E 4 s OC-192 STS-192 STM-64 9953. 280 9621. 504 331. 776 5, 376 DS-1 s or 192 DS-3 s 4, 032 E 1 s or 64 E 4 s Note: Although an SDH STM-1 has the same bit rate as the SONET STS-3, the two signals contain different frame structures. STM = Synchronous Transport Module (ITU-T) STS = Synchronous Transfer Signal (ANSI) OC = Optical Carrier (ANSI) R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 3

SDH and SONET Bit Rate R 4. 0 Marquee Orientation SDH Bit Rate SONET STM-0 51 Mb/s OC-1 STM-1 155 Mb/s OC-3 STM-4 622 Mb/s OC-12 STM-16 2. 48 Gb/s OC-48 STM-64 9. 95 Gb/s OC-192 © 2003, Cisco Systems, Inc. All rights reserved. (STS-1) 4

What is different about SDH vs. SONET? • Together they are a set of global standards that interface equipment from different vendors. SDH is basically the international version of SONET, and SONET can be thought of as the North American version of SDH. • There are some slight differences between SONET and SDH. • The main differences are in the basic SDH and SONET frame formats, but SDH and SONET are essentially identical beyond the STS-3 signal level. The base signal for SONET is STS-1 and the base signal for SDH is STM-1. STS-3 c is equivalent to STM-1 and the lower tributaries can be mapped interchangeably between the two formats from that point on. R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 5

What is different about SDH vs. SONET? (Cont’) • In SDH, both electrical and optical signals are referred to as STM signals. • In SONET, however, electrical signals are called STS and optical signals are referred to as OC. R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 6

SONET • Defined by Bellcore and ANSI T 1. X committees Base rate (High Order) is 51. 84 Mbps (STS-1) STS-1 Synchronous Payload Envelope (SPE) = 50. 112 M used for carrying tributaries or a DS 3 signal Tributaries (Low Order) used for SONET are: VT 1. 5 (SPE Trib) = 1. 728 M for carrying DS 1 (1. 544) VT 2 (SPE Trib) = 2. 304 M for carrying CEPT (E 1, 2. 048) VT 6 (SPE Trib) = 6. 912 M, Never “formalized” same rate as VT Group R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 7

SONET Hierarchy STS-N x 1 STS-N SPE x. N STS-1 SPE Tributaries of Base Signal (Low Order Payloads) Data x 1 DS 3 Broadband STS-N Payloads (High Order Payloads) x 7 VT Group x 1 x 3 x 4 R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. VT 6 SPE VT 2 SPE VT 1. 5 SPE E 1 DS 1 8

STS-1 Frame with VT Mapping 3 bytes 3 87 bytes Section OH J 1 1 STS Pointer 5 Line OH B 3 C 2 G 1 STS-1 SPE Payload DS 3 Mapped or 7 x VTG Mapped F 2 H 4 ptr F 3 K 3 Z 3 VT VT Group Group Vx V T 1 5 R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 9

Points to Remember in SONET • The base layer is the STS-1 SPE Single pointer to get to the STS-1 SPE (50 MB level) ALL tributary signals multiplex (via Pointer Processing) to the STS-1 SPE Each STS-1 has it’s own path overhead TOH is called Section and Line Overhead SS bits (in H 1) is set to 00 Bellcore (Telcordia) Alarming and GR-820 Performance Monitoring Other Nuances: Path Trace is 64 bytes, Orderwire is Mu-Law, Z bytes not used, No J 2, APS is different R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 10

SDH • Defined by ITU-T (previously CCITT) committees Base rate (High Order) is 155. 520 (STM-1) Virtual Container 4 (VC-4) = 150. 336 M used for carrying tributaries or an E 4 signal (or data) Tributaries (Low Order) used for SDH are: VC-11 = 1. 728 M for carrying DS 1 (1. 544) (rarely used in AU 4) VC-12 = 2. 304 M for carrying CEPT (E 1) Also a stuffing option for mapping VC 11/1. 5 M to TU-12 VC-2 = 6. 912 M Just gaining acceptance (TU-2 -Mc) for data VC-3 = 50. 112 M (Same as STS-1 SPE) used for E 3 AND DS 3 R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 11

SDH Hierarchy STM-64 x 64 STM-16 x 16 AU-4 -64 c VC-4 -64 c 9039. 872 Mb/s AU-4 -16 c VC-4 -16 c 2259. 968 Mb/s AU-4 -4 c VC-4 -4 c 564. 992 Mb/s AU-4 VC-4 E 4: 139. 264 Mb/s C-3 E 3: 34. 368 Mb/s DS 3: 44. 736 Mb/s x 4 STM-4 x 4 STM-1 AUG x 3 AU-3 TUG-3 High Order Payloads Containers of Base Signal (Low Order Payloads) TU-3 VC-3 x 7 STM-n AUG AU-n VC-n Synchronous Transport Module TUG-2 Administrative Unit Group: One or more AU(s) Administrative Unit: VC + pointers Virtual Container: payload + path overhead R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. x 1 TU-2 VC-2 DS 2: 6. 312 Mb/s TU-12 VC-12 E 1: 2. 048 Mb/s TU-11 VC-11 DS 1: 1. 544 Mb/s x 3 x 4 12

STM-1 Frame with AU-4 Mapping 9 bytes 3 Regenerator Section OH 1 AU Pointer 5 Multiplex Section OH 261 bytes J 1 B 3 C 2 G 1 F 2 H 4 F 3 VC-4 Payload: C 4 or TUG-3 mapped H 1 H 1 H 2 H 2 H 3 H 3 J 1 B 3 C 2 K 3 Higher Order Path OH N 1 G 1 F 2 H 4 5 bytes C-3 Payload ptr F 2 H 4 TUG-3 C-3 G 1 Payload TUG-2/VC 12 Vx F 3 K 3 V N 1 C Muxed 1 2 Low Order Path OH R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 13

Points to Remember in SDH • The base layer is the VC-4 Container Single pointer to get to the VC-4 ALL Low Order (LO) Signals multiplex (via PP) to the VC-4 Additional pointer to get to VC-3, the STS-1 equivalent: A FUNDAMENTAL DIFFERENCE between SONET and SDH TUG-3 is NOT the same as an STS-1 TOH is called Regenerator Section (RS) and Multiplex Section (MS) Overhead SS bits (in H 1) is set to 01 ITU-T Alarming and ITU-T Performance Monitoring Other Nuances: Path Trace (P-API) is 16 or 64 bytes, Orderwire is A-Law, Z (N 1) bytes used for TCM, APS is different R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 14

SONET Vs. SDH • SONET UPSR = SDH SNCP (Sub-Network Connection Protection) WTR is up to 12 minutes in 1 minute increments “Hold-off” timer for SDH – 0 -10 S in 100 m. S increments • SONET BLSR = SDH MS-SPRing (Multiplex Section – Shared Protection Ring), SDH does not specify MS-SPRing @ STM-4 (but we allow it) • SONET APS = SDH MSP (Multiplex Section Protection) • SONET Mesh/ Virtual Ring = SDH Same as/Extension of SNCP (and this has been around a while in SDH Networks) • SONET Path Trace = SDH Path Access Point Identifier (P-API, or API) • SONET Alarms: CR, MJ, MN = SDH Alarms PMA (Prompt Maintenance Activity), DMA (Deferred Maintenance Activity): We kept the CR/MJ/MN and added the “-PMA/DMA as a suffix R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 15

SONET Vs. SDH (cont…) • SDH Collects Errored Block Seconds, Errored Second “Ratios” • SDH is beginning to use Tandem Connection Monitoring – “Path within a path” Adds additional Path Trace, BIP, FEBE and RDI to a high or low-order path • SONET, STS-SPE (50. 112 M) is the base-rate payload – SDH, the base is 155 M and the VC-3 (STS equivalent) is a “tributary” to the VC-4 • It’s not a central office, it’s an “Exchange” • It’s not a Class 5/ Class 4, it’s a Local Switch and a Transit Switch • It’s not a DCS, it’s a DXC SONET uses 3/3 s and 3/1 s, SDH uses 4/4 s and 4/3/1 s R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 16

Terminology Summary Optical I/O Board Path Type SDH SONET STM-1 OC-3 STM-4 STM-16 OC-12 SONET Not applicable STS-1 VC 4 STS-3 c VC 4 -4 c STS-12 c VC 4 -8 c STS-24 c VC 4 -16 c STS-48 c VC 4 -64 c STS-192 c OC-48 STM-64 OC-192 STM-256 OC-768 R 4. 0 Marquee Orientation SDH © 2003, Cisco Systems, Inc. All rights reserved. 17

Terminology Summary Protection Type Overhead Naming SDH SONET MSP APS/FFP MS-SPRing BLSR SNCP PPMN/UPSR R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. SDH SONET RS - Regenerator Section MS - Multiplex Section Line HP - High Order Path 18

Terminology Summary Alarms SDH SONET LOS LOF RS-TIM TIM-S MS-AIS MS-RDI MS-DEG MS-EXC MS-REI R 4. 0 Marquee Orientation AIS-L RDI-L/RFI-L SD-L SF-L REI-L © 2003, Cisco Systems, Inc. All rights reserved. SDH SONET AU-LOP LOP-P AU-AIS AIS-P HP-UNEQ-P HP-TIM TIM-P HP-SLM SLM-P HP-RDI RDI-P/RFI-P HP-DEG SD-P HP-EXC SF-P HP-REI REI-P 19

Terminology Summary PM Monitored Types SDH SONET Not defined CV – Code Violation EB – Errored Block Not defined BBE – Background Block Error Not defined ES – Errored second Not defined SEFS - Severely Errored Framing Seconds SES - Severely Errored Second Not defined FC- Failure Count UAS - Unavailable Second BBER - Background Block Errored Ratio Not defined ESR – Errored second Ratio Not defined SESR - Severely Errored Second Ratio Not defined R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 20

Terminology Summary PM Monitored Entities SDH SONET Not defined FC-LNE Not defined CV-S Not defined FC-LFE RS-EB Not defined MS-UAS-NE UAS-LNE RS-BBE Not defined MS-UAS-FE UAS-LFE RS-ES ES-S Not defined CV-PNE Not defined CV-LNE Not defined CV-PFE Not defined CV-LFE HP-EB-NE Not defined MS-EB-NE Not defined HP-EB-FE Not defined MS-EB-FE Not defined HP-BBE-NE Not defined MS-BBE-NE Not defined HP-BBE-FE Not defined MS-BBE-FE Not defined HP-ES-NE ES-PNE MS-ES-NE ES-LNE HP-ES-FE ES-PFE MS-ES-FE ES-LFE HP-SES-NE SES-PNE HP-SES-FE SES-PFE R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 21

Terminology Summary PM Monitored Entities (Cont. ) SDH SONET Not defined FC-PNE Not defined FC-PFE HP-UAS-NE UAS-PNE HP-UAS-FE UAS-PFE HP-BBER-NE Not defined HP-BBER-FE Not defined HP-ESR-NE Not defined HP-ESR-FE Not defined HP-SESR-NE Not defined HP-SESR-FE Not defined R 4. 0 Marquee Orientation © 2003, Cisco Systems, Inc. All rights reserved. 22