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1
OTN Overview
Radhakrishna Valiveti
System Architecture Group,
Infinera Corp.
2
What is OTN?
Basic Capabilities in OTN Networks
New Developments
OTN Evolution – Convergence of Layers
Summary
Outline
3
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)
What is OTN?
4
First Gen DMDM Networks (pre-OTN)
Carrier B
Vendor B NE NE
Vendor A NE NE
NE NE
Proprietary DWDM solutions
Carrier A NE
NE
Carrier A
Customer Eqpt (e.g. Router)
Customer Eqpt (e.g. Router) Inter Vendor/Carrier interop
Possible only at the level of client signals
• 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)
5
The OTN Approach
Carrier B
Vendor B NE NE
Vendor A NE NE
NE NE
Intra-Domain interfaces (IaDI). Can incl. proprietary elements
Carrier A NE
NE
Carrier A
Customer Eqpt (e.g. Router)
Customer Eqpt (e.g. Router) 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
6
Network View
IP Layer – Routers Links – Realized via Xport networks
IP
Electrical: Client Mapping, Connection Multiplexing, Grooming, Monitoring, No stranded BW Protection/Restoration
OTN
DWDM
Optical Layer: Add/Drop, Express, Protection/Restoration
7
OTN Architecture
Client OH Optical Payload Unit (OPUk) (transparent client signal transport)
OPUk OH
FEC OH ODUk
Optical Data Unit (ODUk)
Optical Transport Unit (OTUk)
Optical Channel (OCh) (1 OCh per OTU; ITU G.694.1 wavelength grid)
OMSn
OTSn
Optical Multiplex Section (OMS)
Optical Transport Section (OTS)
Multi-Service Clients
Dig
ital
Do
main
Op
tical
Do
main
SONET/SDH SAN Ethernet
OCh
OCh
. . . . . . . . . . .
(k = 1/2/3/4 for 2.510/40/100G) FEC – Enhanced optical reach, BER
No
n A
sso
c O
H (
OSC
) A
sso
c O
H
8
OTN NE Internals CLIENT LINE SWITCHING
Client signal
adaptation
OTN
(O
TU1
, OTU
2, O
TU3
, OTU
4)
Eth
ern
et
(1/1
0/4
0/1
00
Gb
E)
SON
ET/S
DH
(1
55
Mb
/s –
40
Gb
/s)
SAN
(F
ibre
Ch
ann
el, F
ICO
N)
l1
l2
l3
ln
l4
l1
l2
l3
ln
l4
ODUk Bandwidth Management
. . . .
. . . .
OD
U
Mu
x/d
emu
x
OTU
So
urc
e/Si
nk
OTN Client Interfaces
OTN Bandwidth Management
OTN WDM Line Side
• Multi-service support for SONET/SDH, Ethernet and SAN
• OTN handoffs enable multi-vendor inter-working
• Optical interfaces support (OTUk) (Fully standardized)
• G.694.1 wavelength grid
• G.709 Digital Wrapper w/ FEC or Enhanced FEC
• Typically OTUkV (Functionally standardized)
• OTN Overhead & OAMP
• ODUk switching
• Typically ODU0 (1.25G) granularity
• Transparent switching of DWDM line capacity
9
OTN Layers (End-to-End View)
ODU
Client Eqpt
Digital ADM
Optical ADM
Optical ADM
Digital ADM
Client Eqpt
Optical Amp
OTS OTS
OMS
OCh
OTU
Client Signal Trail: e.g. OC192, STM-64, 10GBASE-R
May be part of the same NE
10
Client Signal Mapping (G.709 3/2003)
CBR2G5 AMP OPU1
BMP
CBR10G AMP OPU2
OPU1-4V BMP
CBR40G AMP OPU3
OPU2-4V
OPU1-16V
BMP
OC-48/STM-16
OC-192/STM-64
OC-768/STM-256
No Standard Mappings defined for Ethernet Clients * AMP = Async Mapping Procedure; BMP = Bitsynch Mapping Procedure
11
GMP 40GBase OPU3 TTT
GMP 100GBase OPU4
GMP STM-1,4 OPU0
GMP 1000Base OPU0 TTT
10GBase BMP OPU2e
FC-1200 BMP OPU2e TTT
CBRx BMP OPUFlex
Client Signal Mapping (G.709 12/2009)
* GMP = Generic Mapping Procedure; TTT = Timing Transp. Transcoding OTN fully support Ethernet Clients
12
ODU Multiplexing Hierarchy
Low-Order ODUk
ODU0
ODUflex
ODU1
ODU2
ODU3
ODU3e1
ODU3e2
ODU4
ODU3e1
ODU3e2
ODU1 Muxing
ODU2 Muxing
ODU3 Muxing
ODU4 Muxing
ODU3e1/2 Muxing
ODU1
ODU2
ODU2e
ODU3
ODU4
High-Order ODUk
ODU1
ODU2
ODU3
ODU4
2 8 32 80
4
8 32 80
16 40
4 10
3 10
2
4
13
OTN Multiplexing - Example
OTU3 OTU2e
OTU2
10GbE mapped into ODU2e
OD
U2
e O
H 10G
10GbE
10G
OD
U2
e O
H 10G
ODU2e muxed into
ODU3
OD
U2
e O
H 10G
OD
U3
O
H
OC-192/STM-64 mapped into ODU2
OD
U2
O
H 10G
OD
U2
O
H 10G
10G
OC-192/ STM-64
OD
U2
O
H 10G
ODU2 muxed into same
ODU3
ODU2 OH
10G
ODU3 OH
Client service
ODU2 encapsulation
ODU3 encapsulation
Legend
ODU2e OH
ODU2e encapsulation
14
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
15
Tandem Connection Monitoring (TCM) Segment Protection/Restoration
OTN Network A
OTN Network A
ODU Connection monitored within B (TCM1)
ODU Connection monitored within A (TCM2)
• detects the problem with the working path
• Knows the problem is in their domain
• Switches to the protection path
NE at the edge of Network B
• 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)
NE at the edge of network A (near CPE)
OTN Network B
working
protection
16
Control Plane in Optical Networks
Auto discovery of topology
Route computation
Point-and-click provisioning
Service restoration
• RSVP-TE signaling protocol for dynamic provisioning of paths • Speeds service delivery from A to Z
• OSPF-TE discovers topology & bandwidth • Dynamically advertised as changes occur
• Source-based CSPF circuit routing • Traffic engineering for explicit routing control
• Mesh restoration of multiple failures. Efficient use of bandwidth
Automated control plane for DWDM & OTN
17
ODUflex Applications
• 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
• 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)
Improvement over ODU VCAT
FC
Eth
TDM CBR
ODU-flex 1
ODU-flex 2
ODU (non-flex)
Higher Order (HO)
– ODU (one l)
Eth
TDM CBR
ODU-flex 1
ODU (non-flex)
Higher Order (HO)
– ODU (one l)
ODU-flex 2
VLAN #1
VLAN #2
18
80 tributary slots @ 1.301G (for ODU4 links)
LO ODUj can take any ‘n’ tributary slots
• No bandwidth fragmentation
LO ODUflex(GFP) is resizable – hitlessly (without any traffic impact)
HO ODU4/21 80 TribSlots @ 1¼G
ODUflex(GFP)/3
ODU2
ODUflex(GFP)/6
ODUflex(3GSDI)
ODU0
ODU0
ODU0
Unallocated TribSlot Allocated
TribSlot
/ 4
ODUflex – Tributary Slot Allocation
19
Convergence of Layers
20
Private Line
SONET transport
Co
re /
Bac
kbo
ne
Net
wo
rk
The motivation behind Packet-OTN
IP Core Routers
Transport Network (OTN/WDM)
IP Peering
IP-VPN L2 VPN Internet Access
IPTV VoIP
Service Routers
Wholesale Bandwidth
SAN
Reduce Cost: IP core routers touch 100% of IP traffic at most nodes
Ensure Common convergence layer: Optical + Packet Support
21
P-OTN optimized for packet & multi-service optical
© 2011 Infinera Corporation.
Today Phase I
IP/MPLS
STS/OTN
WDM
Converged WDM/OTN Switching
IP
MPLS
Phase II
IP
Converged WDM/P-OTN
Converged WDM/P-OTN dramatically simplify the network
22
Summary
23
Full function OTN
ODUk (N x ODU3)
OTUk (OTU4)
OTN DWDM Transport
Control Plane & OAMP
e.g., GMPLS, ASON, WSON
ODUj <-> ODUk (ODU2 <-> ODU3)
OTN Multiplexing
client ODUj OTN
OTN
OTN
OTN
OTN
OTN Adaptation
ODUj (ODU2)
ODUj (ODU2)
OTN Switching
Support For Full Range of Fully-Standardized OTN Features
10GbE -> ODU2
Standardized Multi-Service
Platform
Efficient Service
Reconfiguration
High Bandwidth
Inter-Carrier Hand-Offs
Efficient High-Bandwidth Transport
Multi-Layer Management & Automation
24
Efficient – OTN Enabled Network
Single OTN Service Delivery Layer Single protocol-agnostic service delivery layer
Homogenous OAM&P
Standardized Managed multi-service trunks • Tandem Connection Monitoring
100% Transparent transport • Asynchronous mapping • Bit Synchronous mapping • Generic mapping
Integrated OTN + DWDM
SDH Ethernet
Fiber Channel Others
OTN
Carrier A
TCM Level 1
Level 2
Level 3
Domain & Domain Interconnect Supervision
Lead Operator QoS Supervision
User QoS Supervision
OTN
Carrier B
OTN
25
Thank You
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