OTN Overview & Update Jean-Marie Vilain Product Specialist

Agenda OTN Sonet Overview OTN Overview OTN update Ethernet over OTN What’s next…

SONET-SDH structure Sonet / SDH technologies have been out for a while now, the main goal was to transport digital information over fiber, but also support electrical lower rate communication signal overhead payload overhead payload

SONET / SDH supported transport rate SONET-SDH structure SONET / SDH supported transport rate

SONET-SDH structure VCAT/LCAS VCAT/LCAS and GFP offered Automatic Flexible bandwidth and Clear way to map Ethernet traffic In to Sonet

Virtual Concatenation Bandwidth Efficiency 100% Efficiency Increase 67% This table shows the improvements in bandwidth efficiency that can be made by using virtual concatenation instead of contiguous concatenation. For example, traditionally with contiguous concatenation an STS-3c or VC-4 will be used to transport 100 Mb/s fast Ethernet service. This equates to a bandwidth efficiency of 67%. By using virtual concatenation, we can use 2x STS-1s or VC-3s to carry the same service and the bandwidth efficiency rockets to 100%! Even larger efficiency improvements can be made with some other data services.

GFP VCAT/LCAS Ethernet map into SDH/SONET Using GFP

WDM Transmission Services Layer SDH/SONET Layer Optical layer Delivery of services to end customers. SDH/SONET Layer High-speed protection/restoration. Time division multiplexing ADM ADM ADM DXC ADM ADM ADM ADM ADM ADM ADM WDM fiber WDM WDM Optical layer Wavelength division multiplexing High level protection Traditional DWDM networks are point to point and utilized in high capacity links. The OTN enables DWDM ring and mesh networks, with the opportunity for dynamic payload provisioning and reconfiguration of traffic routing. WDM fiber WDM WDM WDM line system WDM line system for fiber saving

ITU G.709 is the OTN Standard Why OTN ITU G.709 is the OTN Standard

Why OTN

Why OTN

OTN mapping structure We can see from the slide that the frame format is very similar to SONET/SDH and that should be no surprise, as G.709 attempts to take the best features of SONET/SDH. It should be noted that the OTN frame is much smaller than the 10G SONET/SDH frame.

OTN Frame Format We can see from the slide that the frame format is very similar to SONET/SDH and that should be no surprise, as G.709 attempts to take the best features of SONET/SDH. It should be noted that the OTN frame is much smaller than the 10G SONET/SDH frame.

OTN Overhead structure The FAS/MFAS provides frame alignment. The Section Monitoring provides Error detection and communication The ODU overhead brings TCM support, Communication channels and Automatic protection switching The OPU overhead adapt the client signal to the optical channel, specifying the type of client signal in the payload

Why the use of OTN over SONET/SDH OTN provide better TCM support Over-multiple Carriers. SDH/SONET only support one TCM vs. 6 TCM for OTN

Forward Error Correction (FEC) FEC provides the following benefits. Improves the BER performance of an existing link Increases the maximum span of a link can extend up to 20km and remove the need of regenerator Improves the overall quality of the link by diagnosing link problems earlier At 10Gb/s there is less optical margin in terms of BER for the same optical power at 2.5Gb/s. This can be compensated for by increasing the optical power or reducing the span. Another approach is to use Forward Error Correction (FEC) in connection with 10Gb/s and above. FEC can increase the optical margin without boosting power margins or reducing the span. RS(255,239). For the FEC processing a OUT row is separated into 16 sub-rows using byte-interleaving. Each FEC encoder/decoder processes one of these sub-rows. The FEC parity check bytes are calculated over the information bytes 1 to 239 of each sub row and transmitted in bytes 240 to 255 of the same sub-row.

ITU G.709 Sup 43 Over-Clocked OTN rates OTU1e – OTU2e The goal here, is to combine multiple 10GE ports from the Core router directly into OTN. Not to be confused with OTU1 which is a 2.7 Gbit/s signal, these are 10G rates Not a big issue with 10GE Wan (9.953 Gb/s) where the signal can be directly map into an OPU2 container This is more a problem with the 10GBASE-R 10GE LAN, where there’s a size mismatch between the containers.

Over-clocked OTU3 - OTU3e1 OTU3e1 OH OPU3e1 = 41.56Gbps FEC Defined in ITU-T G.709 Sup43 Sec9.1 OTU3e1 supports nominal bit rate of 44.57Gbps +/- 20ppm The OPU3e1 is divided into 16 x 2.5G tributary slots (TSs) interleaved within the OPU3e1 payload area OTU3e1 is key for asynchronous bit-transparent mapping of 4 x ODU2e signals

Over-clocked OTU3 - OTU3e2 Defined in ITU-T G.709 Sup43 Sec9.2 OTU3e2 supports nominal bit rate of 44.58Gbps +/- 20ppm The OPU3e2 is divided into 32 tributary slots (TS) of approximately 1.25Gbps; interleaved within the payload area OTU3e2 uses Generic Mapping Procedure (GMP) for mapping 4 x ODU2e signals into OPU3e2 payload area OTU3e2 OH OPU3e2 = 41.61Gbps FEC ODU2e ODTU3e2.8 x4 ODTUG3e2 PT=21 x1 ODU3e2 (H) Mapping MUXing OTU3e2

Ethernet in Carrier Networks EoOTN 10/100M Ethernet link OTU2 Access Routers ODU MUX Access Routers OTU1 GigE link OTU2 , OTU3 or even OTU4 MSPP OTU1 ODU1 mux in ODU2 MSPP OTU2 1GigE in ODU0 in OTU1 Access Routers Access Network OTU1 with ODU0 ENIU

Client Interface cards 100M/GbE 10GbE FC SONET/SDH 10.7G OTN (G.709) DWDM & OLA Powerful Unframed/ frame testing SONET/SDH (10G) OTN (OTU1/2/1e/2e) with FEC 10/100/1000BaseT, Gig-E & 10G Ethernet 1x/2x/4x/10x FC 8130NGE Transponder cards Proper provisioning Power levels Bit Error Rate tests FEC (OTN)

New ODU 0 OTN container ODU0 is a new container size that has been introduced in the G.709 to accommodate efficient transport of Gigabit Ethernet (1.25 Gb/s). OTU1 was not efficient for 1GbE signal with a payload rate of 2.48832Gb/s ODU0 is half the size of an ODU1 container i.e = 1.244 160 Gb/s Gigabit Ethernet does not fit in the OPU0 payload, GMP will be use to insert the Gigabit Ethernet rate inside OPU0 rate Note: ODU0 does not have a physical instance (i.e. there is no OTU0), the signal needs to be multiplexed into a higher layer in order to be transported on the OTN network

ODU0 New ODU 0 OTN container New multiplexing method1 that allows direct ODU0 multiplexing into ODUk (k=2,3,4) in a single stage This multiplexer uses Generic Mapping Procedure (GMP) for ODU0 justification control Where GMP will support various client signals and future new ones. It is a generic procedure for mapping a client signal with any bit rate less than the payload capacity to the ODU.

Technology Overview ODU ODU0 mapping? The mapping of a ODU0 into a ODU1 is done using ODTU01 (optical channel data unit tributary ) where the ODU1 structure is divided into two sections and where both ODU0 are map. Each needed ODU0 are mapped in to the payload using GMP to specific timeslot.

Technology Overview Any client signal can be map into the payload using the below process, where each low order signal will mux into a timeslot and be insert in to the payload

ODUflex is a new OTN variable container introduce in October 2009 Allows for flexible ODU rates for transparent transport of any client signal, it used a similar process to VCAT except that there is no delay because the signal is map in to the same physical container Adapted in 2 ways: For Constant Bit Rate (CBR)client signals Rate = 239/238 x CBR rate For GFP-F mapped packet client signals Rate = N x ~1.25Gbit/s (ODU0) with 1 ≤ N ≤ 80

40GE/100GE Mapping into OTN Wide-area Ethernet transport technologies are necessary to support, for example, the connection of Ethernet switches separated by more than 40 km (typical distance supported by Ethernet standards). ITU-T SG15 is responsible for OTN standardization and IEEE 802.3ba is responsible for 40G/100G Ethernet standardization; both working closely to develop 40GE/100G transport capability over OTN

40GE/100GE Mapping into OTN 40GE with 64B/66B Transcoding 41.25G Using 1024B/1027B 103.125G 40.117G 100GE 40GE GMP GMP ODU4 104.794G OH 104.355G ODU3 40.319G OH 40.15052G 1x 1x OTU4 OTU3 Standard 40GE runs at 41.25Gbps and OPU3 payload is only 40.15 Gbps Therefore, mapping 40GE over OTU3 requires 1024/1027B transcoding adaptation to reduce 40GE coded rate

OTN OTL (OTU3/OTU4) New OTUk & bit rate OTU3 = 43Gb/s OTU4 = 112Gb/s Client OTUk & bit rate OTU3 = 43Gb/s OTU4 = 112Gb/s OPU OH OCh Payload Unit (OPU) Payload ODUOH OCh Data Unit (ODU) Payload OTU OH OCh Transport Unit (OTU) Payload FEC OTUk signal is transmitted over n lanes OTLk.n OTLk.n OTLk.n OTL type & bit rate OTL3.4 = 10.7Gb/s OTL4.4 = 27 95Gb/s OTL4.10 = 11.18Gb/s 1  2  n

Traditional OTN Structure

New OTN Structure