Wp2 upc contribution to a2 2 1 route management
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WP2 UPC Contribution to A2.2.1: Route Management. Route management. Network models Packet-switched/wavelength-switched model Routing models / Route management models Static routing model(s) [ETH, UPC, all partners] Combined intra- and inter domain routing model(s) [ETH, UPC]

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WP2 UPC Contribution to A2.2.1: Route Management

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Wp2 upc contribution to a2 2 1 route management

WP2UPC Contribution to A2.2.1: Route Management

NOBEL: Berlin May 18-19, 2004


Route management

Route management

  • Network models

    • Packet-switched/wavelength-switched model

  • Routing models / Route management models

    • Static routing model(s) [ETH, UPC, all partners]

    • Combined intra- and inter domain routing model(s) [ETH, UPC]

    • Adaptive routing model(s)

    • Predictive routing model(s)

    • Multicast routing model

NOBEL: Berlin May 18-19, 2004


Optical packet and optical burst vs wavelength switched model

Optical Packet and Optical Burst vsWavelength Switched Model

  • Physical

    • Technological requirements – how advanced optical components are expected

    • Complexity of the hardware (node architecture)

  • Computational

    • Node control algorithms complexity

    • Routing algorithms complexity

  • Performance

    • Efficiency, network utilization

  • Flexibility

    • Data formats, bitrates, ...

    • Label switching paradigm – paths (connections) granularity, scalability

NOBEL: Berlin May 18-19, 2004


Optical packet and optical burst vs wavelength switched model1

Optical Packet and Optical Burst vsWavelength Switched Model

  • QoS

    • Difficulty in quality guarantees

    • Hardware and control algorithms complexity

  • Network

    • Control Plane implementation

    • Signalization overhead

    • Adaptation to traffic demands

  • Interworking

    • With legacy networks – edge node operation complexity (adaptation, aggregation, ...)

  • Costs

    • Hardware (node), building of the network, ...

NOBEL: Berlin May 18-19, 2004


Physical technological hardware requirements

Physical – technological, hardware requirements

Optical Packet and Optical Burst vsWavelength Switched Model

NOBEL: Berlin May 18-19, 2004


Computational complexity

Computational complexity

Optical Packet and Optical Burst vsWavelength Switched Model

NOBEL: Berlin May 18-19, 2004


Optical packet and optical burst vs wavelength switched model2

Optical Packet and Optical Burst vsWavelength Switched Model

Performance

Network utilization, efficiency

  • Wavelength switching

    • Not dynamically adopted (in real time) to the actual traffic demands

    • Efficiency up to 9 times worse than in OBS/OPS, very high wavelength consumption

    • Medium blocking probability

  • Burst switching

    • Network utilization higher than at WS (due to statistical multiplexing in optical domain)

    • High blocking probability - optical buffers need for fine network performance

  • Packet switching

    • Very high network utilization (statistical multiplexing in optical domain)

    • Needs FDLs and WC’s for high performance (low PLR)

    • Even with FDLs, packet delay is low due to fast optical switching (without O/E conversion of packet payload)

NOBEL: Berlin May 18-19, 2004


Flexibility

Flexibility

Optical Packet and Optical Burst vsWavelength Switched Model

NOBEL: Berlin May 18-19, 2004


Wp2 upc contribution to a2 2 1 route management

QoS

Optical Packet and Optical Burst vsWavelength Switched Model

NOBEL: Berlin May 18-19, 2004


Network aspects

Network aspects

Optical Packet and Optical Burst vsWavelength Switched Model

NOBEL: Berlin May 18-19, 2004


Optical packet and optical burst vs wavelength switched model3

Optical Packet and Optical Burst vsWavelength Switched Model

Interworking

With legacy networks,edge node operation complexity (adaptation, aggregation, ...)

  • Wavelength switching

    • Lack of aggregation problem

    • Adaptation only in physical layer (e/o or wavelength conversion)

  • Burst switching

    • Burst assembly problem

  • Packet switching

    • Necessity of adaptation the data coming from legacy network to optical packet payload field

    • Packets disordering problem

NOBEL: Berlin May 18-19, 2004


Optical packet and optical burst vs wavelength switched model4

Optical Packet and Optical Burst vsWavelength Switched Model

COSTS

Hardware (node), building of the network

  • Wavelength switching

    • Lower costs then in OBS/OPS case

    • But very high wavelength consumption

  • Burst switching

    • May use cheeper low speed switching elements than in OPS

    • Costs of advanced optical components

    • Low wavelength consumption

  • Packet switching

    • Very high costs of advanced optical components (FDLs units (for buffering, synchronization), very fast tunable wavelenght converters, very fast switching elements, …)

    • Costs of high performance electronic control unit

    • Low wavelength consumption

NOBEL: Berlin May 18-19, 2004


Summary

Summary

Optical Packet and Optical Burst vsWavelength Switched Model

NOBEL: Berlin May 18-19, 2004


Nobel wp3 upc works ops environment

Nobel-WP3 UPC worksOPS environment

  • Previous works - studies on contention resolution algorithms for a single switch

    • UPC contributions in asynchronous, variable length packets scenario

  • Next step - studies on routing strategies for a network scenario

    • Adaptive vs. Multipath

    • Per-packet vs. per-connection

  • Further works

    • QoS management taking into account previous results

NOBEL: Berlin May 18-19, 2004


Nobel wp3 upc works obs environment

Nobel-WP3 UPC worksOBS environment

  • Previous works

    • Studies on contention resolution algorithms for a single switch

    • Burst assembly mechanisms

    • Signaling protocols

  • Next step

    • Studies on the effectiveness of multi-domain contention resolution in a network scenario

    • Studies on different routing strategies for a networks scenario

  • Further works

    • QoS management taking into account the previous results

NOBEL: Berlin May 18-19, 2004


Route management1

Route management

  • Network models

    • Packet-switched/wavelength-switched model

  • Routing models / Route management models

    • Static routing model(s) [ETH, UPC, all partners]

    • Combined intra- and inter domain routing model(s) [ETH, UPC]

    • Adaptive routing model(s)

    • Predictive routing model(s)

    • Multicast routing model

NOBEL: Berlin May 18-19, 2004


Combined intra and inter domain routing model

Combined Intra and Inter-Domain routing model

  • Our Research Focus is on QoS Routing (QoSR) in Optical Networks:

    • Dynamic Intra-AS QoS light-path provisioning (Optical QoS aware IGP)

    • Dynamic Inter-AS QoS light-path provisioning (Optical QoS aware EGP)

      • Coupling between both QoSR mechanisms

NOBEL: Berlin May 18-19, 2004


Wp2 upc contribution to a2 2 1 route management

Combined Intra and Inter-Domain routing model

  • Research Goal: provide a combined Intra and Inter-AS QoS Routing model with the following characteristics:

    • Highly scalable

    • Resilience: survivability

    • Loop-free

    • Support for different CoS and Policy Control

    • Clear cut between QoS aware IGP and QoS aware EGP

    • Per-CoS fast re-route provisioning

    • Efficiency in terms of the trade-off between the updating frequency, and distributing and maintaining routing state information (inaccuracies)

    • Suitable signaling for QoS: requirements of the Control Planes for both routing protocols, IGP and EGP

NOBEL: Berlin May 18-19, 2004


Wp2 upc contribution to a2 2 1 route management

Combined Intra and Inter-Domain routing model

  • Line of work:

    • Survey optical extensions to classical IGPs and EGPs

    • Development of Metrics and Routing Algorithms for both Intra and Inter-Domain QoS Routing

    • Efficient coupling between both Routing Algorithms

    • We also plan to carefully manage how traffic flows so that no starvation of best effort traffic occurs

NOBEL: Berlin May 18-19, 2004


Adaptive routing analyzing the effects of flooding on global network performance

Adaptive routing: analyzing the effects of flooding on global network performance

  • Routing and Wavelength assignment problem (RWA)

    • Not tractable problem, so divided into:

      • Routing sub-problem

      • Wavelength assignment sub-problem

  • Routing sub-problem

    • Static routing

    • Dynamic (adaptive) routing

  • Static routing:

    • Fixed-routing

    • Fixed-alternate routing

    • Does not consider network dynamics

  • Dynamic (adaptive) routing:

    • Adaptive shortest-path routing

    • Least Congested Path (LCP)

    • Includes network dynamics in the route selection

NOBEL: Berlin May 18-19, 2004


Wp2 upc contribution to a2 2 1 route management

Adaptive routing: analyzing the effects of flooding on global network performance

  • Dynamic vs static?

    • Static routing is simpler and not so complex

    • Dynamic routing is more appropriate for high dynamic networks

  • Dynamic routing issues:

    • Route selection must be adapted to network dynamics

    • Flooding mechanism is required

      • Mainly for high dynamic networks

    • Is the network state databases information accurate enough?

      • Routing inaccuracy problem

      • Non-suitable path selection because of having inaccurate network state information

NOBEL: Berlin May 18-19, 2004


Wp2 upc contribution to a2 2 1 route management

Adaptive routing: analyzing the effects of flooding on global network performance

  • Flooding mechanism

    • In an N nodes network, each change results in a N2 messages to be flooded

      • Leads to instability and scalability

    • There are not many contributions on optical networks

    • New techniques must be sought

    • Approaches could be based on:

      • Updating by time (hold-down timer) as an IP extension

      • Updating by number of network state changes

      • Updating by minimum number of available resources

NOBEL: Berlin May 18-19, 2004


Wp2 upc contribution to a2 2 1 route management

Adaptive routing: analyzing the effects of flooding on global network performance

  • Routing inaccuracy problem:

    • Routing algorithms must reduce the impact of selecting routes based on inaccurate routing information

    • New routing algorithms must be sought

    • Not many contributions in optical networks:

    • Approaches based on:

      • Dynamic bypass concept (BBOR):

        • Rerouting through alternative pre-computed paths

      • Prediction (PBR):

        • Route decision according to a “novel” concept of predicted network state information

        • Simultaneously, flooding is “almost” removed

  • In short, efforts must be done to develop new adaptive routing mechanisms which include these factors in the route decision

NOBEL: Berlin May 18-19, 2004


Wp2 upc contribution to a2 2 1 route management

Prediction Based Routing

Usual Routing Algorithms need update messages with information about the network state

Network state information is not accurate:

- Aggregating information

- Triggering of update messages

- latency associated in flooded the update messages

Routing Algorithms utilise inaccurate state information (RIP)

NOBEL: Berlin May 18-19, 2004


Wp2 upc contribution to a2 2 1 route management

Prediction Based Routing

  • Idea: Source nodes can learn which is the better path and wavelength without update messages

  • Dynamic learning according to the routing information obtained in previous connections set-up. (Based in branch prediction)

  • For each wavelength on a path there is a prediction table, PT, to predict the possibility of blocking

  • For each wavelength on a path there is a history register, WR, with information about if in the last cycles the wavelength on that path has been used

NOBEL: Berlin May 18-19, 2004


Prediction based routing

Prediction Based Routing

Index to access PT from wavelength register histories

Prediction: Read two-bit counter value < 2 not blocked, value > 1 blocked

NOBEL: Berlin May 18-19, 2004


Prediction based routing1

Count PT lambda 0

of SP1

Count PT lambda 1

of SP1

Count PT lambda N-1

of SP1

Count PT lambda 0

of SP2

Count PT lambda N_1

of SP2

...

...

>1

>1

>1

>1

<2

<2

<2

SP1

lambda 0

SP1

lambda 1

SP1

lambda N-1

SP2

lambda 0

SP2

lambda N-1

Prediction Based Routing

  • Update PT: PT are updated increasing counter if connection request is blocked and decreasing otherwise

  • Update WR: WR of the wavelength used is updated with 0, and the WR of the unused wavelength are updated with 1

  • Prediction Algorithm:

    Two shortest path, SP1, SP2 and N wavelengths

NOBEL: Berlin May 18-19, 2004


Multicast approach in optical transport networks

Multicast approach in optical transport networks

  • Main idea: to optimize optical resources utilization

  • Lightpaths are established point-to-multipoint to overcome the mismatching between optical and client granularities

  • 1xN Splitters are placed at the optical terminations in order to extend the lightpath to N destinations (N=3 in the example)

NOBEL: Berlin May 18-19, 2004


Multicast approach in optical transport networks1

3

S

1

1

1

2

1

4

1

3

3

5

2

2

1

4

5

Multicast approach in optical transport networks

  • Example: When a connection from 1 to 3 is requested, the optical channel is transparently extended to nodes 4 and 5 (to allocating future connections from 1 to these nodes)

Although resources are wasted firstly, they will be recovered in the future (when new connections from 1 to 4 or 5 arrive).

NOBEL: Berlin May 18-19, 2004


Multicast approach in optical transport networks2

Multicast approach in optical transport networks

  • As it seems difficult to fill a lightpath with traffic generated by a single source to an only destination, the lightpath capacity will be better used if it collects traffic from this source to many destinations.

  • This will only be true if the granularity difference between lightpath and connections accomplish some constraints.

  • Some preliminary simulations show that the applied strategy can perform well under certain conditions.

NOBEL: Berlin May 18-19, 2004


Multicast approach in optical transport networks3

Multicast approach in optical transport networks

  • Work Plan:

    • Start simulations to study the feasibility of the proposed strategy

    • Study how to physically implement the multicast approach

    • Find the ratio between granularities and optimal N

    • To analyze different algorithms to implement the multicast approach

    • Simulate different traffic patterns

NOBEL: Berlin May 18-19, 2004


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