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PCE – OAM Handler in ABNO: a use case of code adaptation in flex grid networks. Francesco Paolucci TeCIP, Scuola Superiore Sant’Anna, Pisa, Italy. PACE Workshop on “New uses of Path Computation Elements” Vilanova y la Geltru , Spain, June 16 th 2014. Control Management. - PowerPoint PPT Presentation
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PCE – OAM Handler in ABNO: a use case of code
adaptation in flex grid networks
PACE Workshop on “New uses of Path Computation Elements”Vilanova y la Geltru , Spain, June 16th 2014
Francesco PaolucciTeCIP, Scuola Superiore Sant’Anna,
Pisa, Italy
Control <-> Management
• Control plane– Discovery and Routing– Path computation– Signaling– Failure recovery
• Management plane– Network Status and Monitoring– Operation and Administration Maintenance (OAM)– SLA verification
• Interaction between planes– Historical separation or limited interaction (not automatic)– New target: pro-active control automatically driven by
OAM events/ conditions– Active Stateful Path Computation Element in ABNO candidate
object
• Active Stateful PCE– Access to TED and LSP-DB– Stateful computation
• Shared protection computation
• Effective restoration
– Active behaviour• Delegated LSP control• LSP resize, modification• LSP instantiation• Optimization Action Chain
•OAM Handler– Network status supervisor– Monitoring correlations
•Databases– TED, LSP-DB
ABNO architecture
Application-Based Network Operation (ABNO) framework.
“A PCE-based Architecture for Application-based Network Operations”
draft-farrkingel-pce-abno-architecture
PCE in Flexible optical networks• Next flexible transponders will support multiple configurable signal generation @given bitrate
• PCE outputs– Suggested frequency slots (n: central frequency, m: width ) – Suggested modulation format (e.g., DP-QPSK, DP-16QAM)– Suggested FEC / code– Single/multi carrier: type and number of sub-carriers
• Hitless flexible operations driven by active PCE– Defragmentation (change n)– Elastic operations (change m)– Dynamic adaptation (change the code)
• Advanced Action Chain– E.g. Defrag + Elastic expand
TED
Active Solver
PCEP Server
Action HandlerLSP-DB
request
update
action list
PCEP
load
action queue
PCReq-new LSP-elastic operation
PCRep-reply to PCReq
PCUpd-active LSP adaptation
PCRpt-LSP adaptation outcome
PCNtfy-TE updates-QoT degradation-failure events
Chain Example: Shift & Expand
5
PCReq (LSP 1: Elastic bit rate increase)1
2 PCUpd (LSP 2: Shift)
4 PCRpt (LSP 2: Shift OK)
5 PCRep (LSP 1: Elastic increase)
7 PCNtf (LSP 1: Elastic incresae OK) FrequencyLSP 1
1 PCReq message
3 RSVP make before break
5 PCRep message
6 RSVP elastic increase
7 PCNtf message
PCRpt message 4
PCUpd message 2
3 LSP 2 shift
6 LSP 1 elastic increase
LSP 2
Code adaptation for flexi Terabit
• Terabit transmission based on Time Frequency Packing– LDPC coding applied to data– Narrow-filtered subcarriers (faster-than-Nyquist) – Coherent detection and DSP
• Scenario 1– 7 subcarriers @ 160Gb/s– 200 GHz width– 8/9 coding– 1.12 Tb/s bitrate -> 1Tb/s info rate
• Scenario 2– More robust transmission needed– 1 subcarrier added– 4/5 coding– 237.5 GHz width– 1.28 Tb/s bit rate -> 1Tb/s info rate
QoT monitoring and forecast
• Quality of Transmission is monitored at the receiver– Post-FEC BER – Variance of acquired data samples
• Event Forecasting– The variance indicates whether a working limit condition is
approaching– FORECASTING post-FEC errors before they occur– Threshold-based alarm event
• QoT monitor– Responsible of monitoring– Responsible of event ntf– Responsible of alarms
0
0,02
0,04
0,06
0,08
0,1
12 14 16 18
"3/4"
"4/5"
"8/9"8/9
4/53/4
Varia
nce
OSNR (dB)
Validation Testbed (PCEP+RSVP)
SSSSSS
Link1 Link2
ADC+Processing
X
TxBVT Rx
Controller
PCCRSVP-TE RSVP-TE
Controller Controller
PCC PCC
ActiveStateful
PCE
QoT monitor
1 - PCNtfy (QoT degradation)2 – PCUpd (LDPC rate adaptation + spectralexpansion)
3 –Path4 –Path
8 –Resv
5 –filter shape(expand)
6 –Resv
7 –filter shape(expand)
9 –LDPC rate adaptation
10 – PCRpt
Pol-Mux
IQ-modulators
Configurable Electrical
Data generation
Tunable carrier comb
BVT Tx
oddch.
evench.
I Q
I Q Pol-Mux
couplers
USBUSBeth
eth
OOK Tx
OOK Rx
PCE-driven code adaptation
• Impairment-aware PCE computes a new code rate:– Extended PCUpd message
– The ERO specifies the code to be applied at ingress/egress node
– LDPC code rate TLV• Alarm triggered by PCEP:
– Novel QoT notify msg– PCE computes the code
– First implementation– PCEP not suitable for OAM
– Path rerouting is the last option
-Receiver transponder id: 1-LSP ownership: 10.0.0.1-Event type: excessive BER value (1)
UPDATE (PCUpd) MESSAGEREPORT (PCRpt) MESSAGE
QoT object
LSP id: 1; src IP: 10.0.0.1 LSP object
-ERO subTLVLDPC code rate: 3/4 (adaptation)
-Flexgrid labeln: -44 -> f=192.825THzm: 19 -> width=237.5GHz (expansion)
ERO object
QoT object
UPDATE (PCUpd) MESSAGE
Hitless data plane operations
• To apply the new coding– Configurable electrical encoder at transmitter, triggered upon
RSVP-TE session is finished– In the overhead, a preamble of each data block includes a 3-bit
field to communicate the code to be applied to the next block– Receiver processes next incoming data block with the new coding– Code adaptation performed with no traffic disruption
0 5 10 15 200.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0 5 10 15 202
3
4
5
6
7
Spec
tral
Effi
cienc
y
Varia
nce
OAM infrastructure
• OAM Agent located at the receiver– OAM session per LSP (per receiver card)
• Hierarchical OAM Agent – Local Agent (node, link, network device…)– Aggregation Agent (area, domain…)– Local correlations when applicable – Scalable design
• Proposed OAM protocol: NETCONF– Support of Asynchronous Notifications (RFC 5277)– TCP connection assures reliability– Hierarchical architecture reduces number of connections at
Handler– Native solution for OAM YANG modeling development
OAM Handler
L L LLLLLLL
A A A
PCE driven by OAM
SSSSSS
Link1 Link2
ADC+Processing
X
TxBVT Rx
Controller
PCCRSVP-TE RSVP-TE
Controller Controller
Local OAM Agent
ActiveStateful
PCE
QoT monitor
2 – PCUpd (LDPC rate adaptation + spectralexpansion)
3 –Path
8 –Resv
5 –filter shape(expand)
6 –Resv
7 –filter shape(expand)
9 –LDPC rate adaptation
10 – PCRpt
Pol-Mux
IQ-modulators
Configurable Electrical
Data generation
Tunable carrier comb
BVT Tx
oddch.
evench.
I Q
I Q Pol-Mux
couplers
USBUSBeth
eth
OOK Tx
OOK Rx
OAM Handler
4 –Path
OAM Handler <-> PCE interaction
• OAM Database instance ->Augmented TED / LSP-DB• OAM LSP-DB: <BER>, <coherent receiver variance>,< ……• OAM TED : <power><amp_gain><…
• Direct PCE<->OAM Handler interface needed?
PCE
OAM Handler
PCEP
TEDOAM TED
LSP-DBOAM
LSP-DB
NETCONF
R
R only(OAM-aware path computation)
R/W
OAM InstanceMain Instance
1) Through ABNO controller2) PCEP (OAM:PCC)3) Dedicated protocol4) Internal API (if co-located)
Conclusions
• Proactive PCE – Fast reaction in presence of network degradations– Computation and dynamic update of additional parameters
• Presented use case– Hitless code rate adaptation in next generation transponders– Active PCE in charge of computing the most suitable
adaptation– Advanced monitoring functions
• ABNO boxes interaction– Close relationship between OAM Handler and PCE– Proposed Hierarchical OAM infrastructure with
NETCONF– Dedicated database extensions/sessions populated by
OAM– Shared handling of the ABNO database sessions
Thank you
• Francesco Paolucci, Scuola Superiore Sant’Anna
ACKNOWLEDGMENTS-collaboration with IDEALIST project
Questions are welcome