Outline - Terena

13/11/14 Sharing of Spectrum and Alien Waves
in and around SURFnet
3RD TERENA ARCHITECT WORKSHOP
Rob Smets – Architect Transport and Light Systems
Outline
•  London CBF and Brussels Photonic Exchange
•  Time and Frequency Transfer in SURFnet’s network
•  100G Alien waves for customers
•  Multi-domain alien-wave demand planning rules
•  Infinera waves on a Ciena light system
• 
Guy Roberts from GEANT Association
(Some of these slides have been presented at CEF2014 Prague)
1 13/11/14 London CBF / Brussels Photonic Exchange
Amsterdam – London CBF
•  Joint Collaboration between NORDUnet and SURFnet
•  Collaboration: NORDUnet leases the fiber, SURFnet installs and
operates the light system. We start with two 100G waves.
•  CBF between ASD001A – ASD002A – LDN001A
• 
• 
For SURFnet puts total number of CBFs to four (Geneva, Hamburg, London, Aachen)
Puts total number of foreign PoPs to six.
•  Driven by desire to connect to services in London directly
•  Installation took place in September 2013 during ECOC 2013
•  Has been in service since December 2013. Expected doubling of
100G services in one year.
2 13/11/14 Amsterdam – London CBF in more detail
London (HEX)
Wherstead
Whickford
Leiston
6500
WL3
79km
17.9dB/18.2dB
78km
17dB/18.2dB
Alien
47km
10.3dB/13.5dB
215km
40.6dB/20.3 dB
IL RAMAN (RX+TX) = 5.4dB
Total IL = 46dB
Gain RAMAN: 25.7dB
(Ppump=2.88W , Pseed=18mW)
53km
12.8dB/14.8dB
10km + 10dB
2.4dB/13.5dB
6500
WL3
6500
WL3
Alien
Amsterdam 1
Amsterdam 2
Zandvoort
Photonic Exchange in Brussels
Hamburg
Amsterdam
PoP
PoP
London
PoP
NORDUnet
PoP
PoP
Brussels
SURFnet
Paris PoP
Geneva
PoP
3 13/11/14 Why and how?
Use cases:
•  Restoration
•  Redundancy
•  For both customer and non-customer facing services
Requirements:
•  Support >10Gbps
•  50GHz ITU grid / 88 channels (all DWDM channels in the C-band)
•  Switch from and to any direction
•  Local add/drop
•  All waves should be presented in a single fiber
Concept
Datacenter SURFnet
WSS-DIA
MLA
MLA
SURFnet
OSI_1
WSS
Local Add/Drop
WSS
To ASD
SURFnet
OSI_2
MLA
BMD2
CMD44
Virtual BMD2
& CMD44s
(Derived Adj.)
Ca. 10 Km NDSF + patching: 7dB (max)
EDFA
To GEN
Local Add/Drop
Datacenter NORDUnet
MLA
MLA
NORDUnet
OSI_1
WSS
To LON
WSS
MLA
WSS-DIA
To HB
NORDUnet
OSI_2
Line fiber (0 km) + padding
4 13/11/14 Restoration using OPS switches
London
6500
Amsterdam 2
OPS
OCLD
TOADM
Ch. 28 Gr. 3
Ch. 68
Gr. 7
add/drop
OPS
OCLD
ASD-LON link
OTS
Amsterdam 1
ROADM
(50 GHz)
TOADM
OTS
OTS
OTS
add/drop
Gr. 3 Gr. 3
Ch. 28
6500
add/ Ch. 68
drop
OCLD
OPS
WSS
Ch. 28
OPS
Ch. 68
add/drop
OCLD
ROADM
WSS (50GHz)
6500
OTS
BRU-ASD link
To/from Hamburg
BRU001A_CPL1P
Ch. 28
add/
Ch. 68 drop
OTS
6500/CPL
LON-BRU link
OTS
DIA
OTS
ROADM
(50GHz)
Brussels - NORDUnet
OTS
DIA
OTS
To/from
Geneva
ROADM
(50GHz)
Brussels - SURFnet
Time and Frequency Transfer
5 13/11/14 Time and Frequency Transfer in SURFnet
•  Objective: Allow clocks to synchronize their time with an accuracy
better than 500ps
•  Two approaches that allow the far end to be compensated for the
offset to the middle of a loop:
• 
• 
Maintain unidirectional traffic and calibrate the system to compensate for the
asymmetry due to different length of each fiber in the fiber pair
Implement bi-directional transmission and amplification on a single fiber and only
calibrate the time difference occurring in the amplifier and in fiber due to dispersion.
•  SURFnet aims to make adjustments to the network that allows
institutions to deploy White Rabbit systems beyond 10km.
Semiconductor Optical Amplifiers
1470nm
In: 1490nm
Out: 1470nm
In: 1470nm
Out: 1490nm
1490nm
LEDN001A_BIDIRAMP_01 (BDOA100B901)
1490nm
In: 1470nm
Out: 1490nm
In: 1490nm
Out: 1470nm
1470nm
LEDN001A_BIDIRAMP_02 (BDOA100B902)
6 13/11/14 Experimental setup over dark fiber
•  In 2013 we have started with the following set-up:
VSL-Delft
(Dutch Metrology Institute)
1dB
M
S
LEDN001A
Campus TU-Delft / DT001B
-1.0dBm
1.7dBm
-17.3dBm
5km G.652
3.4dB
3.4dB
35.5km G.655
9.5dB
-24.0dBm
-7.7dBm
-26.7dBm
19dB
81km
G.655
135km, mixed G.655/G.652 fiber
ΔT
19.6dB
1dB
M
S
-1.0dBm
0.5km
G.652
-24.0dBm
0.8dB
14km G.652
3.1dB
0.8dB
1.4dB
NIKHEF-Amsterdam
(National Institute for Subatomic Physics)
ASD001A (SARA)
ASD002A (TC2)
Findings:
•  BiDi amplifiers are placed asymmetrical in the link.
• 
• 
• 
• 
Link engineering becomes significantly more complex in the absence of sim-tooling
Gain of SOAs difficult to control by changing the electrical pump current
Amplifiers produce about 19dB of gain on 1470nm and 1490nm
Compatibility with fiber infrastructure is good.
•  There are two types of optical budget: too much and too little!
• 
• 
• 
• 
Initial tests showed a positive budget of 0.1dB on worst link and wavelength combination
After cleaning a positive budget of 2.0 to 3.5 dB exists
Total budget equals: 20dB + PTX – SRX = 52 – 57 dB depending on transceiver
combinations.
Total losses equal: 17.3dB between Delft and Leiden and 26.7dB between Amsterdam
and Leiden sites.
•  Both slaves lock
• 
• 
• 
• 
• 
Round trip delay of 668,981,165ps corresponds to 136km of fiber (272km round trip).
Frequency offset of -0.3*10-13 Hz/Hz with a spread of 6*10-13 Hz/Hz over several hours.
12 digit accuracy of the frequency already present.
On-going work to calibrate the small difference between 1490nm and 1470nm waves.
Measurements are ongoing. We expect to achieve time accuracy around 500ps.
7 13/11/14 Press release
100G Alien waves for customers
8 13/11/14 Extend DWDM waves into the customer’s domain
requires a New Demarcation Box: Optical Gate
Router
Router
MGMT
TRX
TRX
MGMT
MGMT
DWDM
OG
Institution A
OG
TRX
Institution B
SURFnet
Virtualization of the management function
MGMT
Router
Router
TRX
TRX
TRX
OG
Institution A
DWDM
OG
SURFnet
TRX
TRX
Institution B
Challenges
•  Optical plane:
• 
• 
DWDM signals are transported over an infrastructure that is intended for unengineered links on campus
A proper CFP!
•  Cross domain management:
• 
• 
• 
• 
• 
• 
Fault Management
Configuration Management
Accounting
Provisioning
Security
Controlled and accessible by both SURFnet and institutions
Optical Gating and Management Information Exchange Functionality
may be required to:
• 
• 
• 
• 
• 
Isolate and protect the DWDM network
Monitoring
Measure frequency
Test photonic path between two gateways
Exchange of management information and instructions (may be virtualized in a
datacenter)
9 13/11/14 Two Scenario’s
•  CPE equipment (router or switch) of both customers is the same:
• 
• 
• 
Vendor has DWDM blade in portfolio that interoperates with light system
Vendor has DWDM blade in portfolio that does not interoperate with light system
Vendor has no DWDM blade in portfolio but does support a CFP slot.
•  CPE equipment (router or switch) of both customers is different:
• 
• 
Both CPEs have a CFP slot
At least one of the CPEs does not have a CFP slot -> no solution
Can we find such a CFP that:
•  Interoperates with SURFnet’s DWDM equipment
•  Compatible with Topology of SURFnet7 and SURFnet8
•  Is affordable! (<$10,000)
ACACIA 100G Coherent CFP
What if you:
•  optimize power of transmission impairment compensating ASICs;
•  start using 28nm/20nm semiconductor process;
•  start using Silicon Photonics Integrated Circuits and InP chips;
•  pay extreme detail to power consumption and heat management?
Source: Acacia Inc.
Source: Flickr
• 
• 
• 
• 
• 
• 
• 
DWDM single lambda solution
50GHz C-band grid
25ps PMD tolerance & 40 ns/nm CD tolerance
Compatible with >1000km network solutions
< 15dB OSNR for up to 2000km
SD-FEC, HD-FEC
<24-26W
• 
• 
• 
• 
• 
• 
• 
<7.5W for DSP
<7.5W for ADC/DAC/SERDES
Ca. 5W for PIC
< 10W for misc. funct.
24W for ZR range
Path to smaller form factors like CFP2
Supported by hosts
10 13/11/14 Multi-domain alien-wave planning
Spectrum Sharing on Cross Border Fibers
Three important cross-border fibers
•  Amsterdam – London
Photonic Exchange in Brussels!
•  Amsterdam – Geneva
•  Amsterdam – Hamburg
Photonic Exchanges in Hamburg/Geneva ?
11 13/11/14 SURFnet’s CBFs
•  In operation for several years using a variety of signals
• 
• 
• 
• 
• 
10Gbps with electronic dispersion compensation
40Gbps waves
40Gbps alien waves
100Gbps waves
100Gbps alien waves
•  GEN & HB CBFs are the CBFS we have the most knowledge on its
performance and capabilities
• 
• 
• 
• 
Non-linearity (is King!)
OSNR performance (is King Kong!)
Chromatic dispersion and PMD (piece of cake!)
Operational issues (escalation matrix and testing of alarms)
•  Can we predict performance impact of an alien wave in order to
validate demands end-to-end traversing multiple domains.
• 
• 
• 
With reasonable accuracy
Without complex, time consuming and expensive high-fidelity simulations
Using planning tooling as provided by vendor of light system
Fiber Non-Linearity & Dispersion
Non-Linearity:
•  No DWDM interfaces that use Back-Scatter-Propagation or other
non-linearity compensation.
•  Stick to the linear Gaussian noise model
• 
• 
SPM and XPM present themselves as additive Gaussian noise
Neighboring channels with different modulations
• 
• 
Fixed penalty that adds to OSNR budget
Guard channel
Dispersion:
•  Chromatic Dispersion: Linear additive
•  PMD: Sum of max. DGDs per domain.
12 13/11/14 OSNR validation using FoM
•  Each DWDM interface has a certain OSNR budget.
•  EDFA amplification has matured.
• 
Little difference in EDFA behavior of different vendors.
•  Translate multiple-span link to single span, single EDFA link.
• 
16dB
Each traversed domain is represented by a single span.
17dB
23dB
23dB
20dB
17dB
16dB
13dB
13dB
TX
RX
L=10*log10(40+20+20)=19dB
L=10*log10(40+50+50+100)=23.8dB
RX
TX
L=10*log10(200+200)=26dB
Cannot validate this
Can validate this
RX
TX
25.6dB
TX
L=10*log10(240+400+80)=28.6dB
25.6dB
RX L=10*log10(360+360)=28.6dB
Anteneh Beshir, Roeland Nuijts, et.al. “Survivable Impairment-Aware Traffic Grooming”, Networks and Optical Communications (NOC), 2011 16th European Conference on Optical Communications
Emmanuel Desurvire, “Erbium-Doped Fiber Amplifiers: Principles and Applications”
Example: ASD-GEN and ASD-HB
• 
Amplifier nodes
• 
Total length
• 
100Gbps PM-QPSK
• 
All demands pass!
• 
ASD-GEN:
• 
• 
• 
• 
• 
• 
• 
• 
• 
22 ASD-GEN
8 ASD-HB
1500km ASD-GEN
600km ASD-HB
1.5dB OSNR margin ASD-GEN
6.2dB OSNR margin ASD-HB
FoM(ASD-GEN)=1910 with 1.5dB margin: FoM(ASD-GEN,max)=2700
FoM(GEN-ASD)=2053 with 1.5dB margin: FoM(GEN-ASD,max)=2900
FoM(avg)=2800
ASD-HB:
• 
• 
FoM(ASD-HB)=720 with 6.2dB margin: FoM(ASD-HB)= 3001
FoM(HB-ASD)=775 with6.2dB margin: FoM(HB-ASD,max)=3230
FoM(avg)=3115
Average FoM to calculate with is approx. 2960,
Difference between GEN & HB CBF = 0.5dB (ROADM filters 2x)
13 13/11/14 Infinera waves on a Ciena light system
14

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