OTN Overview Radhakrishna Valiveti System Architecture Group, Infinera Corp.
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Outline What is OTN? Basic Capabilities in OTN Networks New Developments OTN Evolution – Convergence of Layers Summary
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What is OTN? Next Generation SONET/SDH • Terabit/sec capacity on fibers (using DWDM) • Higher client signal rates (1G, 2.5G, 10G, 40G, ...)
Transparent Client Signal Transport • Bits & Timing
Support efficient multiplexing of services onto a wavelengths Enhanced OAM
• Beyond SONET (no TCMs), SDH (1 TCM)
Protection schemes
• Linear Protection (support existing SONET/SDH mechanisms) • Ring Protection (support existing SONET/SDH mechanisms) • Shared Mesh protection (New)
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First Gen DMDM Networks (pre-OTN) Proprietary DWDM solutions
Carrier A
Carrier B
NE
Carrier A NE NE
Customer Eqpt (e.g. Router)
NE NE
NE
NE
NE
Vendor B
Vendor A
Inter Vendor/Carrier interop Possible only at the level of client signals
Customer Eqpt (e.g. Router)
• End to end Service realized in the form of multiple segments • Client to wavelength mapping • No end-to-end service management (only possibility is to examine the client signal at various points along the circuit) 4
The OTN Approach Intra-Domain interfaces (IaDI). Can incl. proprietary elements
Carrier A
Carrier B
NE
Carrier A NE NE
Customer Eqpt (e.g. Router)
NE NE
NE
NE
NE
Vendor B
Vendor A
Standard Inter-Domain (IrDI) i/f
• Digitally wrap Client signals. Wrappers can be monitored in transit • Monitoring: • Connectivity Verification • Connection monitoring: end-to-end, or in segments • Maintenance Signals • Generic Communication Channels 5
Customer Eqpt (e.g. Router)
Network View IP
OTN
DWDM
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IP Layer – Routers Links – Realized via Xport networks
Electrical: Client Mapping, Connection Multiplexing, Grooming, Monitoring, No stranded BW Protection/Restoration
Optical Layer: Add/Drop, Express, Protection/Restoration
OTN Architecture
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Assoc OH Non Assoc OH (OSC)
Optical Domain
Digital Domain
SONET/SDH
Ethernet
OH OH OH
SAN
Optical Payload Unit (OPUk) (transparent client signal transport)
Client
Optical Data Unit (ODUk)
OPUk FEC
ODUk
Multi-Service Clients
OCh OCh
Optical Transport Unit (OTUk)
(k = 1/2/3/4 for 2.510/40/100G) FEC – Enhanced optical reach, BER Optical Channel (OCh) (1 OCh per OTU; ITU G.694.1 wavelength grid)
........... OMSn
Optical Multiplex Section (OMS)
OTSn
Optical Transport Section (OTS)
OTN NE Internals l2 l3 l4
ODUk Bandwidth Management
OTN WDM Line Side • G.694.1 wavelength grid • G.709 Digital Wrapper w/ FEC or Enhanced FEC • Typically OTUkV (Functionally standardized) • OTN Overhead & OAMP
OTN Bandwidth Management • ODUk switching • Typically ODU0 (1.25G) granularity • Transparent switching of DWDM line capacity SAN (Fibre Channel, FICON)
Ethernet (1/10/40/100 GbE)
SONET/SDH (155Mb/s – 40Gb/s)
OTN (OTU1, OTU2, OTU3, OTU4)
SWITCHING LINE
ln
Client signal adaptation
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l1 l2 l3 l4
....
....
ln
OTU Source/Sink
ODU Mux/demux
l1
CLIENT
OTN Client Interfaces • Multi-service support for SONET/SDH, Ethernet and SAN • OTN handoffs enable multivendor inter-working • Optical interfaces support (OTUk) (Fully standardized)
OTN Layers (End-to-End View) May be part of the same NE
Client Signal Trail: e.g. OC192, STM-64, 10GBASE-R
Client Eqpt
Digital ADM
Optical ADM
Optical Amp OTS
OTS OMS OCh OTU
ODU 9
Optical ADM
Digital ADM
Client Eqpt
Client Signal Mapping (G.709 3/2003) CBR2G5 OC-48/STM-16
CBR10G OC-192/STM-64
CBR40G OC-768/STM-256
AMP BMP
OPU1
AMP BMP
OPU2
OPU1-4V AMP BMP
OPU3
OPU2-4V OPU1-16V
No Standard Mappings defined for Ethernet Clients 10
* AMP = Async Mapping Procedure; BMP = Bitsynch Mapping Procedure
Client Signal Mapping (G.709 12/2009) 10GBase
FC-1200
BMP
TTT
CBRx
1000Base
40GBase
OPU2e
BMP BMP
TTT
OPUFlex
GMP
TTT
OPU2e
GMP
OPU0
OPU3
100GBase
GMP
OPU4
STM-1,4
GMP
OPU0
OTN fully support Ethernet Clients * GMP = Generic Mapping Procedure; TTT = Timing Transp. Transcoding 11
ODU Multiplexing Hierarchy Low-Order ODUk
ODU0 ODU1
ODU1 Muxing
ODU2 Muxing
ODU3 Muxing
ODU4 Muxing
2
8
32
80
4
16
40
8
32
80
4
10
High-Order ODUk
ODU1
ODU1
ODUflex ODU2
ODU2
ODU2 ODU3e1/2 Muxing
ODU2e
ODU3 ODU4
12
3
10
ODU3 2
ODU4
4
ODU3e1
ODU3e1
ODU3e2
ODU3e2 ODU3 ODU4
OTN Multiplexing - Example ODU2e muxed into ODU3
10GbE mapped into ODU2e
10G
ODU2 OH
10G
ODU2e OH
10G
ODU3 OH
ODU2e OH
ODU2e OH
10G
10G
10GbE OTU2e
OTU3
ODU2 muxed into same ODU3
ODU2 OH
10G
OTU2 ODU2 OH
10G
OC-192/ OC-192/STM-64 STM-64 mapped into ODU2
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Legend
10G 10G
Client service
ODU2 OH
ODU2 encapsulation
ODU2e OH
ODU2e encapsulation
ODU3 OH
ODU3 encapsulation
Tandem Connection Monitoring OTN Network A
OTN Network B
OTN Network A
ODU Connection monitored within B (TCM1) ODU Connection monitored within A (TCM2)
• TCM1 & TCM2 being monitored concurrently • Network operators need to agree on the TCM layers to use (no dynamic allocation of TCM layers to domains) • Allows arbitrary nesting of TCM layers (subject to layer availability) • ODU frame includes Overhead (OH) for 6 TCM layers
TCM layer Used for: - Connectivity Verification, PM, Protection/Restoration triggers 14
Tandem Connection Monitoring (TCM) Segment Protection/Restoration OTN Network B
OTN Network A
working
OTN Network A
protection ODU Connection monitored within B (TCM1) ODU Connection monitored within A (TCM2)
NE at the edge of Network B NE at the edge of network A (near CPE) 15
• detects the problem with the working path • Knows the problem is in their domain • Switches to the protection path • Gets (data plane) notification of defect in working path • Uses hold-off timer to prevent initiating switchover (i.e. allow the nested protection attempt to succeed)
Control Plane in Optical Networks
Automated control plane for DWDM & OTN
Auto discovery of topology Route computation Point-and-click provisioning
Service restoration
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• OSPF-TE discovers topology & bandwidth • Dynamically advertised as changes occur • • • •
Source-based CSPF circuit routing Traffic engineering for explicit routing control RSVP-TE signaling protocol for dynamic provisioning of paths Speeds service delivery from A to Z
• Mesh restoration of multiple failures. Efficient use of bandwidth
ODUflex Applications FC
ODU-flex 2
TDM CBR
ODU (non-flex)
•
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VLAN #1
ODU-flex 1
Eth
• •
Improvement over ODU VCAT
Higher Order (HO) – ODU (one l)
Stop the proliferation of ODU containers Suited to CBR signals of arbitrary rates, • e.g. map 8GFC into ODUflex, NOT 8GFC to ODU2 • ODU2e used to map 10GBASE-R signal is not called ODUflex (but can be considered the first ODUflex) No need for deskew buffers required to support ODU VCAT
ODU-flex 1
Eth VLAN #2
TDM CBR
• • • •
ODU-flex 2
ODU (non-flex)
Higher Order (HO) – ODU (one l)
New use for ODUflex Packet Traffic – rates not coupled to that of the physical interface (logical flows) Uses GFP-F encapsulation for packets ODUflex rate is N x (TS in HO-OPUk)
HO ODU4/21 ODUflex – Tributary Slot Allocation 80 TribSlots @ 1¼G
80 tributary slots @ 1.301G (for ODU4 links)
ODUflex(3GSDI)
ODU0 ODU0 ODU0 ODUflex(GFP)/3/ 4
LO ODUj can take any ‘n’ tributary slots • No bandwidth fragmentation
LO ODUflex(GFP) is resizable – hitlessly (without any traffic impact) ODUflex(GFP)/6
ODU2
Allocated TribSlot 18
Unallocated TribSlot
Convergence of Layers
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The motivation behind Packet-OTN Service Routers
Core / Backbone Network
IP-VPN
L2 VPN
Internet Access
VoIP
IP Peering IPTV
IP Core Routers
SONET transport
SAN
Private Line
Wholesale Bandwidth
Transport Network (OTN/WDM)
Reduce Cost: IP core routers touch 100% of IP traffic at most nodes Ensure Common convergence layer: Optical + Packet Support 20
P-OTN optimized for packet & multi-service optical Phase I
Today IP/MPLS
Phase II IP
IP
MPLS
STS/OTN
WDM
Converged WDM/OTN Switching
Converged WDM/P-OTN
Converged WDM/P-OTN dramatically simplify the network 21© 2011 Infinera Corporation.
Summary
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Full function OTN Standardized Efficient High Multi-Service Service Bandwidth Platform Reconfiguration Inter-Carrier Hand-Offs OTN Adaptation
OTN Switching
OTN Multiplexing
Efficient High- Multi-Layer Bandwidth Management Transport & Automation OTN DWDM Transport
OTN OTN OTN OTN OTN
ODUj
ODUj
ODUj
ODUj <-> ODUk
ODUk
OTUk
10GbE -> ODU2
(ODU2)
(ODU2)
(ODU2 <-> ODU3)
(N x ODU3)
(OTU4)
client
Control Plane & OAMP
e.g., GMPLS, ASON, WSON
Support For Full Range of Fully-Standardized OTN Features 23
Efficient – OTN Enabled Network
Single protocol-agnostic service delivery layer
Single OTN Service Delivery Layer Integrated OTN + DWDM
Homogenous OAM&P Standardized Managed multi-service trunks • Tandem Connection Monitoring 100% Transparent transport
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Carrier A SDH Ethernet Fiber Channel Others
OTN
Carrier B
OTN
• Asynchronous mapping
TCM Level 1
• Bit Synchronous mapping • Generic mapping
Level 2
Lead Operator QoS Supervision
Level 3
User QoS Supervision
OTN
Domain & Domain Interconnect Supervision
Thank You
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