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Towards a Transparent and Proactively-Managed Internet. Ehab Al-Shaer School of Computer Science DePaul University. Yan Chen EECS Department Northwestern University. Motivations. The Internet has evolved to become a un-cooperative ossificated network of networks

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Towards a transparent and proactively managed internet
Towards a Transparent and Proactively-Managed Internet

Ehab Al-Shaer

School of Computer Science

DePaul University

Yan Chen

EECS Department

Northwestern University


  • The Internet has evolved to become a un-cooperative ossificated network of networks

    • Network has to be treated as a blackbox

      • Performance of even neighboring networks are opaque

      • Inter-domain routing based on policies but not performance

      • Have to resort to overlay networks which are suboptimal

    • Diagnosis and fault location extremely hard

  • Network config management reactive and expensive

    • Reactive configurations: tune after deployment

    • Vulnerable: manually handled and subject to conflicts

    • Imperative & fragmented: need to access several specific devices in order to implement a service goal

Proposed solution i transparent internet
Proposed Solution I: Transparent Internet

  • Every network shares its measurement and management information with other networks when necessary (glass box)

    • Link-level performance: delay, loss rate, available bandwidth, etc.

    • Management info

      • Configuration: QoS setting, traffic policing

      • Middle box settings: firewalls, etc.

  • The information sharing

    • As part of the inter-domain protocols: Transparent Gateway Protocols (TGP)

    • Other applications: leverage DHT

Analogy to the airline alliance
Analogy to the Airline Alliance

  • When airlines compose multi-lag flights, they need more than just route info.

    • Type of aircraft, # of vacancies, probability of punctuation, etc.

  • Such open model is mutual beneficial

    • Provide the best flight composition for clients

    • Similarly, open network model can provide best communications for applications

Proposed solution ii proactive configuration management
Proposed Solution II: Proactive Configuration Management

  • Proactive verification: configuration verified and translated to different vendor specific devices

  • Proactive validation: Test the configuration changes on the real archived network traffic without interrupting the main operation network

  • Autonomic configuration: configurations are auto-tuned dynamically to achieve the “objectives

Dynamic Validation: auto-tuning








Provides a completely transparent view of the Internet to networks and applications

  • Diagnosis & trouble shooting becomes extremely easy

    • No more Internet tomography needed

  • Flexible inter-domain routing

    • Not just based on policy or # of AS/hops

    • Flexible metrics based on bandwidth, latency, etc.

  • Global traffic engineering

    • Each AS performs its own local traffic engineering

    • Provide AS path-level routing guide

  • Unified framework that applications query (push/pull) info as needed

    • Streaming media, content distribution

    • Anomaly/security applications

Flexible inter domain routing
Flexible Inter-domain Routing

  • Multiple routing paths with TGP

    • Incorporate measurement info into AS paths

    • Bandwidth-intensive and latency-intensive applications can take different AS paths.

  • Challenge: inter-domain routing based on bandwidth without making reservation

  • Solution: Discretize the bandwidth for better stability

    • Though stability is a classical problem, not unique to TGP

Global traffic engineering
Global Traffic Engineering

  • For the current Internet, only local optimum is achieved in each AS

    • Allowing the network to handle all traffic patterns possible, within the networks ingress-egress capacity constraints (e.g. two phase routing)

  • With global information, we can potentially achieve global optimum (or Nash equilibrium)

    • Each AS is a selfish individual

    • A center (or each AS) infers the Nash equilibrium

    • Each AS can try the Nash equilibrium, or attempt to benefit itself based on the inferred Nash equilibrium

Example of benefit of global te





Example of Benefit of Global TE

1G traffic to AS 1

AS 4

AS 2


AS 5

AS 1

1G traffic to AS 1

AS 3

Example of benefit of global te1










Example of Benefit of Global TE

  • Without Global TE

1G traffic to AS 1

AS 4

AS 2


AS 5

AS 1

1G traffic to AS 1

AS 3

Example of benefit of global te2









Example of Benefit of Global TE

  • With Global TE

1G traffic to AS 1

AS 4

AS 2


AS 5

AS 1

1G traffic to AS 1

AS 3

Unified transparency framework for various functionality
Unified Transparency Framework for Various Functionality

  • Sharing of anomaly/security-related measurement

    • Various characteristics of traffic: heavy hitter, heavy changes, histogram, etc.

    • Self-diagnosis to survivability

  • Adaptations

    • Routing adaptations at router level or application level

Practical issues and solutions
Practical Issues and Solutions

  • Incentives for information sharing

    • Mandatory for next-generation Internet ?

    • Alliance model for incremental growth

  • Security/cheating: Trust but verify

    • Trust most of the info shared but periodically verify

      • Much easier than the current Internet tomography unless many ASes collude

    • Verification part of the protocol

      • Some fields in the packet headers designed for that purpose

Measurement info to share
Measurement Info to Share

  • Basic metrics

    • Delay, loss rate, capacity, available bandwidth

    • Demand (or traffic volume) and application types

  • Intra-AS Measurement Info

    • Link-level info

      • Queried only when necessary

    • Aggregated Info

      • OD flow level info

      • Path segment b/t entry and exit points in each AS

  • Inter-AS Measurement Info

    • General AS relationship

    • AS-level topology

    • Inter-AS link metrics

Transparent internet architecture
Transparent Internet Architecture

Combined w/ routing info and

export to neighboring ASes

through TGP protocol

Provide global retrievable

Management Information Base (MIB)

with DHT

Network link-level monitoring



Algorithm design

Realistic simulation


  • Network topology

  • Web workload

  • Network end-to-end latency measurement

Analytical evaluation

PlanetLab tests

Tgp mib dissemination architecture



always update




DHT mesh

TGP MIB Dissemination Architecture

  • Leverage Distributed Hash Table - Tapestry for

    • Distributed, scalable location with guaranteed success

    • Search with locality



data plane

Dynamic Replication/Update

and Replica Management

Replica Location



SCAN server

Overlay Network Monitoring

network plane

Adaptive Overlay Streaming Media


UC San Diego

UC Berkeley


HP Labs

  • Implemented with Winamp client and SHOUTcast server

  • Congestion introduced with a Packet Shaper

  • Skip-free playback: server buffering and rewinding

  • Total adaptation time < 4 seconds


  • A tomography-based overlay network monitoring system

    • Selectively monitor a basis set of O(n logn) paths to infer the loss rates of O(n2) paths

    • Works in real-time, adaptive to topology changes, has good load balancing and tolerates topology errors

  • Both simulation and real Internet experiments promising

  • Built adaptive overlay streaming media system on top of TOM

    • Bypass congestion/failures for smooth playback within seconds

Tie back to scan
Tie Back to SCAN

Provision: Dynamic Replication

+ Update Multicast Tree Building

Replica Management:

(Incremental) Content Clustering

Network DoS Resilient

Replica Location: Tapestry

Network End-to-End Distance Monitoring

Internet Iso-bar: latency TOM: loss rate

Contribution of my thesis
Contribution of My Thesis

  • Replica location

    • Proposed the first simulation-based network DoS resilience benchmark and quantify three types of directory services

  • Dynamically place close to optimal # of replicas

    • Self-organize replicas into a scalable app-level multicast tree for disseminating updates

  • Cluster objects to significantly reduce the management overhead with little performance sacrifice

    • Online incremental clustering and replication to adapt to users’ access pattern changes

  • Scalable overlay network monitoring

Existing cdns fail to address these challenges
Existing CDNs Fail to Address these Challenges

No coherence for dynamic content


Unscalable network monitoring - O(M ×N)

M: # of client groups, N: # of server farms

Non-cooperative replication inefficient

Problem formulation
Problem Formulation

  • Subject to certain total replication cost (e.g., # of URL replicas)

  • Find a scalable, adaptive replication strategy to reduce avg access cost

Scan scalable content access network
SCAN: Scalable Content Access Network

CDN Applications (e.g. streaming media)

Provision: Cooperative

Clustering-based Replication

Coherence: Update Multicast

Tree Construction

Network Distance/ Congestion/ Failure


User Behavior/

Workload Monitoring

Network Performance


red: my work, black: out of scope