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Long Term Network Scenarios based on OBS/OPS. Partners : - Telecom Italia - Alcatel SEL AG - Alcatel CIT - Lucent Technologies Nederland BV - Marconi Communications ONDATA GmbH - Siemens. - Telefonica - FhG-HHI - IBBT - UCL - IKR - University of Stuttgart - UPC - ICCS.

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long term network scenarios based on obs ops

Long Term Network Scenarios based on OBS/OPS

  • Partners:

- Telecom Italia

- Alcatel SEL AG

- Alcatel CIT

- Lucent Technologies Nederland BV

- Marconi Communications ONDATA GmbH

- Siemens

  • - Telefonica

- FhG-HHI

- IBBT

- UCL

- IKR - University of Stuttgart

- UPC

- ICCS

Workpackage 3

Advanced Burst/Packet Switching [draft_v0]

Gert Eilenberger, Michael Schlosser

agenda
Agenda

The presentation is structured in two parts:

  • Objectives / Overview (Gert Eilenberger)
  • TCP over OBS (Michael Schlosser)
agenda1
Agenda
  • Objectives / Overview (Gert Eilenberger)
  • TCP over OBS (Michael Schlosser)
targeted network architectures
Targeted Network Architectures

PhoneHome

PhoneHome

Music

Gaming

Music

Gaming

Applications

Applications

SmartBiz

SmartBiz

Management

Management

Voice

@Home

Voice

@Home

Video

Video

Service

Service

TV

User

User

Element

Element

Interactive

Voice

Multimedia

Services

Services

Softswitch

Control

Control

Network Capabilities

User Location

User profile

Storage

Resource

Broker

Multicast

VPN

L3 Packet

L3 Packet

Security

Packet Network Services

QOS

Charging

AAA

DSL/FTTU

Broadcast

L2 Packet / Optical

L2 Packet / Optical

GigE / SAN

SAN/NAS

Optical Network Services

G-MPLS

Ethernet

GRID

LL

Core

Core

Metro

Access

Access

NOBEL WP3

motivation for burst packet switching
Motivation for Burst/Packet Switching
  • Goal: Converged multi-service network with end-to-end QoS and multiplexing gain on network level

Converged burst/frame

switching network

(new Layer 2 transport service)

Premium

Best effort

Quasi 2 networks

(packet switched)

same technology

stat. mux.

Overprovisioning to get

Best effort

Premium

unused

premium

quality

premium

Isolated best effort network

Isolated premium network

(packet)

Status quo:

2 networks

2 technologies

(circuit/packet)

Premium

Best effort

Isolated premium network

Isolated best effort network

(pure TDM)

motivation for burst packet switching 2
Motivation for Burst/Packet Switching (2)
  • Architecture options

MSN

Pure IP

IP/OXC

IP/DXC

Data services

TDM services

Edge Routers

Edge Routers

Edge Routers

Edge Routers

IP

router

IP

router

Burstification

unit

Burst/Frame Switch

(service agnostic)

Optical Cross Connect

Core Router

SDH/SONET Cross Connect

 Scalability

 QoS

 Costs

 Integrated CP

 Scalability

 QoS

 Costs

 Flexibility

 QoS

 Opt. technology

 Flexibility

 Multi-layer control

extended long term scenario
Extended long-term scenario

The new L2 network service with its hybrid circuit/burst/packet switching capabilities will be fully integrated into the GMPLS control plane (full vertical integration)

wp3 objectives
WP3 Objectives
  • Network and node architectures for high throughput optical burst/packet core and metro networks
  • Evolution from wavelength (circuit) switched to burst/packet switched optical networks: exploit improved statistical multiplexing
  • Exploit transparent opt. wavelength/burst/packet switching to reduce excessive electronic processing for reduced overall cost
  • Optimal balance between optical and electronic technologies in terms of performance and cost
  • NovelCP and MP functions adapted for optical burst/packet networks (performance monitoring, protection and restoration).
  • End-to-End QoS support in opt. burst/packet layer (reservation, allocation, signalling, signal regeneration etc.)
  • Possible extensions and/or evolution of standards
wp3 key achievements
WP3 Key Achievements
  • Data Plane: Definition of requirements and traffic profiles for burst/packet networks and nodes
  • Data Plane: Various solutions for burst, packet and hybrid network architectures (dimensioning, performance)
  • Control Plane: Concepts on architectures and functions specific for burst/packet networks (routing, QoS, GMPLS)
  • Requirements and assessment of technologies for optical and opto-electronic burst/packet switching solutions
  • Evolution trends
  • … contained in >560 pages of deliverables
apson adaptive path switched on
APSON: Adaptive Path Switched ON
  • Migration concept via APSON to OBS/OPS networks
g 709 frame switching concept
G.709 Frame Switching Concept
  • Aggregation of client packets into equally sized containers: G.709 Frames
    • Frame Aggregation Unit at network ingress and egress.
  • Switching of each individual G.709 frame.
    • Connection less forwarding.
  • Connection oriented bandwidth reservation and labeling.
  • Continuous G.709 OTUx connections on transmission links.
core network dimensioning

3

1000 DSL users

Installed

access rates

on 1GBit/s

1

concentrator link

2.5

DSL

0.8

Eth 10

Overdimensioning

Eth 100

large web server,

2

LAN access

0.6

data center

to WAN,

Bandwidth efficiency

1000 users

0.4

1.5

super computers

0.2

talking to

each other

1

100MBit/s

1GBit/s

10GBit/s

100GBit/s

0

0

2

4

10

10

10

Mean bandwidth on core link

Aggregation factor

Core Network Dimensioning
  • Statistical Multiplexing in Core Networks
    • Aim: Reliable bandwidth estimation in packet based networks
      • Dimensioning rules for core links
    • Guidelines for the activity
      • Use knowledge of installed base andmeasurement of core link occupation
        • Typical provider knowledge
      • Avoid assumptions on user behavior and application mix.
        • Not predictable, outdated before consolidation
    • Expected result
      • Modified network dimensioning rules
        • independent of user behaviour
        • exploiting statistical multiplexing
virtual topology design for obs ops ust ikr
Virtual Topology Design for OBS/OPSUST-IKR
  • Motivations for virtual topologies in OBS/OPS
    • Introduction scenario for OBS/OPS into wavelength-switched networks
    • Cost-optimal network design: reduce number of burst-switched interfaces by optical bypassing
    • Exploit lightpaths services for resilience and capacity adaptation
  • Combination of burst-switched and wavelength-switched networksin client-server hybrid optical network
  • But: dense virtual topologies also reduce statistical multiplexing gain

 Integrative network design needed including effective contention resolution

optical burst transport networks obtn ust ikr
Optical Burst Transport Networks (OBTN)UST-IKR

OBTN Components

  • Use optical bypassing where possible
  • Allow constraint alternate routing
  • Assign shared overflow capacityfor alternate routes to improve statistical multiplexing(capacity share is defined by b)
  • Apply effective contention resolutionin nodes to achieve high QoS

Summary

  • Reduction in burst-switched interfacescompared to OBS
  • Only small penalty in network resource efficiency
  • Overall high QoS

Burst-switched trunk ports

Comparison for COST CN network at 10-5 burst loss

why physical obs node design

OBS

node

edge

router

Physical limitations:

  • Component availability
  • Signal degradation (BER)
    • Noise
    • Crosstalk
    • Nonlinearities
Why physical OBS node design ?

What throughput can be achieved with state of the art components?

throughput of tas nodes with 4 fibers at 10 gbit s

12

256

10

8

148

132

Throughput [Tbps]

6

96

4

2

10

0

0

NRZ

NRZ

NRZ

RZ

RZ

RZ

modulation format

SOA type

Gain-clamped SOAs have to be used! NRZ modulation is superior

Throughput of TAS Nodes with 4 Fibers at 10 Gbit/s

maximum throughput due to physical limitations

maximum number

of wavelengths per fiber

allowed throughput to achieve a burst loss rate < 10-6 (effective throughput)

Reference

SOA

Conventional

SOA

Gain-clamped

SOA

orion combining packets and circuits
ORION: Combining Packets and Circuits
  • ORION functionality
  • ORION node architecture
wp3 migration scenarios
WP3 Migration Scenarios

BS over dyn. l

WR-OBS APSON ORION G.709 FS

OBS/OPS

Static l

Dyn. l

time

Field

deployment

2015

Product

status

Research

lab

status

2010

2005

“From semi-static to dynamically reconfigurable optical networks”

technology

agenda2
Agenda
  • Objectives / Overview (Gert Eilenberger)
  • TCP over OBS (Michael Schlosser)
tcp introduction
TCP – Introduction
  • TCP (Transmission Control Protocol) is the dominating transport protocol in the internet.
  • More than 80 % of the IP traffic today uses TCP on the transport layer.
  • TCP establishes an end to end connection:
    • Connection oriented
    • Reliability
    • Flow control
    • Congestion Control

Application Oriented

Layers

L 5-7 (e.g. FTP)

L 4 (TCP)

L 3 (IP)

L 2 (OBS)

L 1

Transport Layer

Network Layer

Link Layer

Physical Layer

introduction to obs

BCP

Introduction to OBS
  • How does OBS work?
    • Incoming packets are assembled into bursts in the edge of the network.
    • Prior to the transmission of a burst, a Burst Control Packet (BCP) is sent, which configures all the intermediate nodes.
    • The optical burst is transmitted through the core of the network without any conversion to the electrical domain at intermediate nodes.
    • Upon arrival at the destination edge node, it is disassembled into packets

IP packets

Edge router

Edge router

Core router

Core router

interaction of tcp and obs
Interaction of TCP and OBS

TCP

Delay

Losses

Reordering

Aggregation of packets

Losses (No buffering)

“Aggregated” Losses

Deflection Routing

OBS

research within the tcp taskforce
Research within the TCP Taskforce
  • Topics:
    • Many TCP flows (highly aggregated traffic in metro and core networks)
    • Delayed Acknowledgements
    • Dependence of TCP performance on number of TCP segments of one flow in a burst
    • Performance of TCP with Deflection Routing
  • Applications:
    • FTP traffic (long-living TCP connection, bulk transfer)
    • HTTP traffic (short-lived TCP connections, short transfers )
  • Scenarios:
    • Single Client/Server behaviour
    • Behaviour of many Clients and Servers
effect of important parameters on tcp performance
Effect of important parameters on TCP performance
  • Investigations from Siemens / Telefonica
number of tcp segments
Number of TCP segments
  • Investigations from Telefonica
tcp performance with deflection routing

Path B

Path A

Server

Client

TCP Performance with Deflection Routing
  • TCP is sensitive to Deflection Routing.
  • Deflection Routing is useful for contention resolution, as the performance degradation due to deflection routing is considerably smaller than the degradation due to burst losses.
  • The aggregation of more packets out of one TCP flow in a burst has positive impact on TCP performance with deflection routing.
conclusion
Conclusion
  • TCP performs well over OBS networks when an appropriate TCP parameter set is used and there is aggregation of multiple TCP flows into bursts.
  • Deflection Routing has a negative impact on the TCP performance, but it is useful for contention resolution, as the performance degradation due to deflection routing is considerably smaller than the degradation due to burst losses.
outlook for nobel 2
Outlook for NOBEL 2
  • Taskforce will continue work
  • New TCP variants
  • Traffic source models derived from measurements from NOBEL partners,
  • Influence of new application mixes
  • Influence of traffic asymmetry (metro networks)
  • Derivation of optimized traffic dependent parameter sets (e.g. max. burst timer/sizes)
  • Generalization of burst reordering problem in high-speed core networks
slide32

WP3

Thank you for your attention!

slide33
Additional slides (could be shown in strongly compressed form if time allows)

- Will be presented as poster

connection oriented ops scenario
Connection-oriented OPS scenario
  • Main Property: Shared WDM links
    • Several wavelengths to choose from on the same output fibre
  • Problem:
    • Algorithm to map the Optical Virtual Circuits (OVCs) into the output wavelengths
  • Solution:
    • At OVC set up: Assign the OVC to the optimum wavelength
    • Using a dynamic wavelength assignment during the OVC live: In case of congestion, move the OVC to another wavelength using a Wavelength Selection (WS) algorithm
qos provisioning different ws algorithm per service category

10-1

TSWS

LBWS

SKWS

10-2

10-3

Packet Loss Rate (PLR)

10-4

10-5

10-6

0.4

0

0.5

1

1.5

2

2.5

Granularity D

1.2

QoS provisioning : Different WS Algorithm per Service Category
  • Provide K different categories of service based on K different WS algorithms
    • Each WS algorithm presents different performance
    • Thus, we can map the WS algorithm into the service categories according to the QoS requirements of these service categories
  • Case study:
    • 3 WS algorithms
    • 3 categories of service
  • Problem:
    • The WS algorithms do not have performance alignment with the optical buffer granularity (D)

D = (FDL length / Average packet size) x (Vt / Vp)

  • Possible solution:
    • Redesigning the Optical Buffer architecture

TSWS: Two State WS LBWS: Loss Bounded WS SKWS: Sequence Keeping WS

qos provisioning proper optical buffer architecture

1

RT

LS

10-1

BE

10-2

10-3

Packet Loss Rate (PLR)

10-4

10-5

10-6

10-7

10-8

0

0.2

0.4

0.6

0.8

1

Granularity D

QoS provisioning: Proper Optical Buffer Architecture
  • Non consecutive FDL
    • Base: D = 0.4
    • Sequence: multiples of 1.2 / 0.4 = 3
    • Example: buffer of 6 FDLs
      • Sequence: 0, 1, 2, 3 (1 x 3), 6 (2 x 3), 9 (3 x 3)
  • As a result:
    • Performance alignment of the WS algorithms
    • Optimum QoS provisioning:
      • Real Time (RT)
        • Lowest PLR of the SKWS algorithm
      • Loss Sensitive (LS)
        • Bounded PLR
      • Best Effort (BE)
        • Acceptable PLR (lowest PLR of the TSWS algorithm)
qos provisioning proper optical buffer architecture1
QoS provisioning: Proper Optical Buffer Architecture
  • Consistency of the solution:
    • The suggested Optical Buffer Architecture depends on
      • Propagation rate (Vp), which depends on the optical fibre in use
      • Transmission rate (Vt), which is a design parameter
      • Average IP (MPLS) packet size, which is a quasi stable parameter
wp3 headlines and key messages
WP3 Headlines and Key Messages
  • Motivation for burst/packet switching in transport networks
    • Convergence layer for TDM and IP required
  • Targeted network architectures (issues in core and metro)
    • Core: Convergent networks for TDM and IP
    • Metro: Packet (Eth) dominated solutions
  • OBS/OPS network scenarios and solutions:
    • Buffer limited packet network, Data Plane & CP issues, TCP over OBS
  • Hybrid circuit/burst/packet network scenarios and solutions
    • ORION, APSON, G.709 FS, WR-OBS
  • Technologies (optics vs. electronics):
    • all-optical solutions not mature yet

Layered Model

motivation for burst packet switching 1
Motivation for Burst/Packet Switching (1)

Pure IP (IP backbone with big, fat routers)

  • Features:
    • No dedicated aggregation function (done in the router line card)
    • Point to point links
    • Best packet multiplexing and routing flexibility
  • Main issues = complexity and costs
    • Network Processor: Mio packets/s to handle
    • Many and complex protocols (control plane)
    • High speed memory + scheduling
    • High line card cost
    • Will reach scalability limits (equipment critical size/capacity)
    • Transit traffic has to be processed in each node

Pure IP

Edge Routers

Core Router

Future proof scenario?? (used here as reference)

motivation for burst packet switching 21
Motivation for Burst/Packet Switching (2)

Current generation crossconnects (SDH, OXC)

  • Features:
    • Aggregation router (traffic sink)
    • Packet over SONET (POS) interfaces
    • Point to point links, circuit switched
    • Sub-wavelength granularity switching (VC SONET/SDH hierarchy)
  • Main Issues:
    • Connectivity limitations (N2 problem; N= nb of nodes)
    • Low filling of the resources due to traffic partitioning
    • Virtual concatenation
    • Multi-hopping  rerouting of traffic in the IP layer
    • Need for finer granularities and dynamic reconfiguration

IP/OXC

Edge Routers

IP

router

Cross Connect

Difficult trade-off: connectivity vs. resource efficiency when choosing the granularity

slide41

OPXC Nodes - Preliminary Conclusions

  • Modeling work has already started and will continue in the second year
  • Preliminary results indicate the following with respect to the aforementioned architectures:
    • Class-I, Total Transported Capacity (BER: 10-15no FEC):
    • 20 nodes x10Tb/s all-optical WCs
    • 10 nodes x10Tb/s o/e WCs
    • Class-II, Total Transported Capacity (BER: 10-15no FEC):
    • 5 nodes x10Tb/s all-optical WCs
    • 20 nodes x10Tb/s o/e WCs
  • Class-II o/e outperforms the O-O due to the inherent noise emission of the XPM-MZI of the latter. Class-I O-O has stepper non-linear transfer function.
wp3 advanced packet burst switching
WP3: Advanced Packet/Burst Switching

Deliverables

  • D4: “Requirements for burst/packet networks in core and metro supporting high quality broadband services over IP” (M6) 
  • D16: “Preliminary definition of burst/packet network and node architectures and solutions” (M14)  under finalization
  • D23: “Definition of hybrid opto-electronic burst/packet switching node structures and related management functions” (M20)
  • D32: “Preliminary report on feasibility studies on opto-electronic burst/packet switching nodes” (M24)
wp3 advanced packet burst switching1
WP3: Advanced Packet/Burst Switching

Activities

  • A3.1

Optical core & metro burst/packet network & node architecture & evolution

  • A3.2

Optimal balance of opt. and el. technologies (transparency vs. O/E/O)

  • A3.3

Novel control & management functions for optical burst/packet networks

  • A3.4

QoS in optical burst/packet layer (reservation, allocation, signalling, regeneration)

  • A3.5

Contribution to possible extensions and/or evolution of standards

wp3 data plane aspects
WP3 Data Plane Aspects

Network & node architectures, solutions for core and metro (1)

  • OCS network scenarios and solutions:
    • Multi-granular OXCs combine wavelength switching, waveband switching, and fibre switching to reduce port count
  • New network architecture to converge circuit, packet and flow switching
    • Burstification by concatenation of packets (slotted approach)
    • Buffer limited network concept
    • New techniques for the best effort traffic to improve the packet loss rate
  • Several optical packet cross-connect architectures are under study and benchmarking against other architectures (e.g. IST-DAVID). Study on both opto-electronic and all-optical solutions.
  • Optical Node architectures
    • Comprehensive analysis of SOA based broadcast and select architecture
      • Impact of noise, crosstalk, SOA saturation and dynamics on node size, cascadability
      • Impact of modulation formats (NRZ, RZ, RZ-DPSK)
      • Limits of effective throughput due to physical impairments and burst losses
    • Analysis of AWG based architecture
wp3 data plane aspects1
WP3 Data Plane Aspects

Network & node architectures, solutions for core and metro (2)

  • Hybrid circuit/burst switching solutions
    • APSON concept (Adaptive Path Switched Optical Network)
      • Design options and QoS concepts for APSON (preliminary analysis and evaluation)
      • Migration concept via APSON to OBS/OPS networks
    • ORION: combining packet and circuit switching
      • Node level simulations with different traffic statistics
      • Re-ordering when overspilling on packet-per-packet basis
        • Overspill per flow
        • Develop and evaluate different algorithms
      • Planned: lightpath re-entry (Even less packet handling, more complex control)
    • G.709 Frame Switching concept
      • Opto-electronic approach for circuit and burst switching in the same node
      • Reduced processing effort for packet type traffic
      • New L2 functionalities: Bypass switching of transit traffic, protection, restoration, QoS
      • Good scalability towards Terabit/s nodes for future IP dominated transport networks
    • WR-OBS architecture
      • Wavelength routing of bursts
      • Centralized control node employing two-way reservation
      • Providing QoS guarantees
wp3 data plane aspects2
WP3 Data Plane Aspects

Traffic aggregation and performance of OBS networks

  • Traffic models for OBS networks
    • Different aggregation levels
      • Single wavelength per burst assembly queue
      • Multiple wavelengths per burst assembly queue
    • Impact of long-range dependence in OBS traffic
  • Analysis of burst aggregation strategies in OBS networks
    • Extension of studies and analysis on
      • Burstification algorithms and resulting burst size distributions and burst arrival rates
      • Traffic models and traffic characterization in OBS edge nodes
  • First concepts for reduction of blocking probabilities in OBS networks
  • End-to-end performance analysis for OBS networks
    • Preliminary analytical study assuming full wavelength conversion capability
  • Analysis of QoS differentiation techniques for OBS
    • Offset time based and preemption based
  • Impact of OBS on TCP performance
    • Impact of deflection routing
      • Effect of reordering and influence on different TCP flavours
    • Effect of burst loss probability on TCP performance, depending on the number of users generating traffic
wp3 control and management aspects
WP3 Control and Management Aspects
  • Control Plane for Burst/Packet networks (GMPLS applied to OBS)
    • Existing CP and MP architectures and functions, potential extensions of standards
    • Study of potential solutions for the Control Plane in OBS networks: Adaptation of current routing and signaling protocols (GMPLS) to OBS.
    • Labeled optical burst switching
    • Signaling issues
      • Analysis of one-way and two-way reservation techniques
      • Effect of reservation techniques on TCP throughput
  • Novel control & management functions for optical burst/packet networks
    • Routing in OBS networks: Development of a burst routing strategy on top of a MPLS like connection-oriented optical network (under study).
    • Routing in OPS networks: Design and evaluation of two different routing algorithms for OPS networks, namely the Flow-multipath routing (MPLS like, connection-oriented) and the Packet-adaptive routing (connectionless) (under study).
  • QoS in optical burst/packet layer (reservation, allocation, signalling...)
    • A method for providing QoS in OBS networks was proposed. The method is called Burst Class Differentiation and consists of assigning different burst lengths and different burst contention resolution rules to the different classes of traffic (under study).
    • A scheme of different Service Categories (ATM like) for connection-oriented (MPLS like) OPS networks was proposed and evaluated.
wp3 technology aspects
WP3 Technology Aspects
  • Potential building blocks for OBS nodes
    • Assessment of switching techniques
      • MEMS (only for large bursts)
      • Fast optical switches (SOAs, LiNbO3 switch array, AWG + tunable lasers)
    • Realizations in optics
      • Requirements of optical devices for OBS networks
  • Assessment of technologies (optics vs. electronics)
    • All-optical OADM and OXC offer less functionality compared to O-E-O
    • Optical performance monitoring still unresolved
    • Upgrading from low-cost/slow reconfiguration to fast reconfiguration when advanced optical components become available
  • Opto-electronic Multi-Terabit packet switching
    • Electronic technologies for signal processing
    • Optical technologies for space switching (e.g. 40 Tbit/s optical space switching matrix, based on an integrated optical technology
    • Exploitation of WDM techniques to minimise the number of in line buffers
wp3 interaction with other wps
WP3 Interaction with other WPs
  • WP1: Provide inputs on burst/packet network scenarios and layering aspects to the NOBEL network vision.
  • WP2: Exchange info on Routing Management for burst/packet networks.
  • WP4: CP requirements/concepts to provide QoS in the new L2 burst/packet transport service.
  • WP6: Harmonization of burst/packet network and node architectures to be implemented by WP6.
  • WP7: Exchange of technology requirements and specifications for burst/packet nodes
wp3 outlook for 2005
WP3 Outlook for 2005
  • Extension of first results
  • Achieve a clear view on future advanced burst/packet network architectures
    • Quantify complexity/performance trade-offs in BS/PS networks
  • Roadmaps and evolution scenarios for their introduction
    • specify functional solutions in data, control and management plane (in particular for end-to-end QoS in burst/packet networks),
    • assess the underlying technologies for their potential implementation.
  • Contribute and impact future directions in standardisation activities on burst/packet networks from the viewpoint of a European network vision.