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A Bandwidth Estimation Method for IP Version 6 Networks. Marshall Crocker Department of Electrical and Computer Engineering Mississippi State University October 13, 2006. Outline. Introduction to Bandwidth and Estimation Motivation IPv4 Estimation Techniques

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A Bandwidth Estimation Method for IP Version 6 Networks

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A bandwidth estimation method for ip version 6 networks

A Bandwidth Estimation Method for IP Version 6 Networks

Marshall Crocker

Department of Electrical and Computer Engineering

Mississippi State University

October 13, 2006



  • Introduction to Bandwidth and Estimation

  • Motivation

  • IPv4 Estimation Techniques

  • IPv6 Overview and Estimation Technique

  • Simulation Experimentation

  • Conclusions and Future Work

What is bandwidth

What is Bandwidth?

  • Important characteristic of data networks

    • How much data

    • How fast

  • Determined by two primary properties

    • Physical Link Capacity

    • Infrastructure Utilization

% Load

100 Mb/s

10 Mb/s


What is bandwidth estimation

What is Bandwidth Estimation?

  • Nodes attempt to estimate network bandwidth

    • Determine minimum physical capacity called Bottleneck Bandwidth

    • Determine unused capacity called Available Bandwidth

  • Estimations are used in many different ways

  • Many different techniques for performing estimations

100 Mb/s

10 Mb/s

90% Load

Applications of bwe

Applications of BWE

  • End-to-end flow control

Decrease Rate



Sending rate less than BWE?

Increase Rate

Applications of bwe1

Applications of BWE

  • Server selection for downloads and streaming media

  • Peer-to-peer selection

    • Connect to peers with most bandwidth

  • Traffic Engineering

    • Adjust routing/switching for optimal operation

  • Capacity Provisioning

    • Increase/decrease capacity as needed






  • BWE valuable for a number of applications

  • IPv4 techniques

    • Suffer from various flaws

    • Limited due to nature of the network

    • No single technique suitable for all applications

    • Evolving network technologies affect theories

  • IPv6 offers framework for improved estimation technique

    • Efficient

    • Flexible

    • Accurate

    • Simple

Ipv4 estimation techniques

IPv4 Estimation Techniques

  • All measurements are passive

  • Examine how network delivers data

    • Packet spacing

    • Packet delay

    • Packet dispersion

    • Statistical

Ipv4 estimation techniques1

IPv4 Estimation Techniques

  • Each suffer from one or more

    • High level of complexity

    • Poor efficiency

    • Limited accuracy

    • Application specificity

  • Each method is susceptible to one or more

    • Network load

    • Cross-traffic

    • Packet-size variability

    • Probing packet size

    • Train length

    • Cross-traffic routing

Incorrect ipv4 bandwidth estimation scenario

Incorrect IPv4 Bandwidth Estimation Scenario

Ip version 6

IP Version 6

  • Next generation Internet Protocol

  • Improves on IPv4

    • Expanded addressing from 32 bits to 128

    • Simplified header

    • Improved extension and option support

  • Extension support provides framework for improved bwe technique

Ipv6 header

IPv6 Header

32 bits

Ver 6

Traffic Class

Flow Label

Payload Length

Next Hdr.

Hop Limit

Source Address

Destination Address




Ipv6 extensions

IPv6 Extensions

  • Several different extensions

    • Routing

    • Fragmentation

    • Destination options

    • Authentication

    • Security

    • Hop-by-hop

  • Examined by every hop

  • Provides instructions for each hop

  • Only two options currently defined

    • Jumbo payload

    • Router alert

Proposed hop by hop options

Proposed Hop-by-Hop Options

  • Traceroute

    • Each hop inserts address

    • Record forward/backward path

    • Not accepted by IETF

  • Connection Status Investigation (CSI)

    • Request statistics/attributes for each hop

    • IP address

    • Bandwidth

    • Type

    • Number of transmitted/received bytes/packets

    • Number of errors

Ipv6 timestamp option

IPv6 Timestamp Option

  • CSI would have been extremely useful

  • Rejected by IETF due to complexity, security, and proprietary concerns

  • A timestamp option was defined for IPv4 but had limited use

  • An IPv6 timestamp option has much more potential including bandwidth estimation

Ipv4 timestamp deficiencies

IPv4 Timestamp Deficiencies

  • IPv4 timestamp option limited in usefulness

    • Can only hold timestamps for up to 9 hops without addresses

    • Room to hold 4 hops with addresses

    • No standard for defining timestamp format

    • IPv4 routers services packets with options slower

Ipv6 timestamp

IPv6 Timestamp

  • IPv6 timestamp properties

    • Enough room to hold timestamp records for every hop

    • Predefined timestamp format

    • Timestamp at incoming and/or outgoing interfaces

Ipv6 timestamp format

IPv6 Timestamp Format

32 bits

Next Hdr.

Hdr. Ext Len

Option Type

Option Data Len

Record Count


TS Type



Hop Limit Base



Upper Part of IPv6 Address

Lower Part of IPv6 Address






Lk Type

Hop Number


Ipv6 timestamp bwe

IPv6 Timestamp BWE

  • Define bandwidth as number of transmitted bits per unit time

  • Expand to include start and end transmit times

  • Use start/end transmit times of packet and packet size to calculate capacity

  • Send two timestamp packets back-to-back

  • Timestamp of first packet and timestamp of second packet = t1 and t2

  • Size of first packet and link layer size used in final calculation

Bottleneck bandwidth estimation

Bottleneck Bandwidth Estimation


TS = 15

TS = 10



Bottleneck bandwidth estimation1

Bottleneck Bandwidth Estimation

  • Relies on back-to-back queuing

  • Count field in TS record ensures back-to-back

  • Smaller tail packet helps back-to-back queuing

Available bandwidth estimation

Available Bandwidth Estimation


TS = 20

TS = 10




Available bandwidth estimation1

Available Bandwidth Estimation

  • Relies on cross traffic to introduce packet separation

  • Constantly changing value

  • Applications must send estimations frequently

Simulation experimentation

Simulation Experimentation

  • Simulation experiments used to compare and evaluate IPv6 Timestamp method

  • Measured against comparable IPv4 method called the cartouche method

  • Cartouche method uses packet trains and examines packet spacing to estimate BW

Simulation setup

Simulation Setup

Simulation setup1

Simulation Setup

Estimation method parameters

Estimation Method Parameters

Ipv6 estimation results

IPv6 Estimation Results

Scenario 1 Scenario 4

Cartouche estimation results

Cartouche Estimation Results

Scenario 1 Scenario 4

Ipv6 estimation frequency

IPv6 Estimation Frequency

Ipv6 estimation frequency1

IPv6 Estimation Frequency

Cartouche estimation frequency

Cartouche Estimation Frequency

Cartouche estimation frequency1

Cartouche Estimation Frequency

Cartouche estimation frequency2

Cartouche Estimation Frequency

Cartouche estimation frequency3

Cartouche Estimation Frequency



  • Presented IPv6 bandwidth estimation using timestamp hop-by-hop option

  • Advantageous over existing methods

    • Efficient

    • Simple

    • Flexible

    • Accurate

  • IPv4 bandwidth estimations are limited due to the nature of the network

  • Outperforms comparable IPv4 Technique

Future work

Future Work

  • Extended simulation models

    • Diverse network properties and conditions

    • Additional hardware and communications models

    • Additional host and network models

  • Real world implementation

  • Development of network control techniques, protocols and applications such as a “Cognizant” version of TCP

    • Aware of network

    • Intelligently respond to network and conditions

    • Fairly use network resources

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