IDMaps: A Global Internet Host Distance Estimation Service

1
IDMaps A Global Internet Host Distance
Estimation Service

• Group Member Weizheng Gao, Yi Ji, Yanjun Zhang

2
Outline

• Background
• Overview of IDMaps
• IDMaps Architecture
• Conclusion
• Questions and Comments

3
1. Background

• Requirement from real world
• Methods not good enough
• Unicast Multicast
• Services we want
• SONAR HOPS

Internet Distance Map Service (IDMaps)
4
2. Overview of IDMaps

• IDMaps can quickly and efficiently learn network
• distance, it can be used upon any points on the
  Internet.
• IDMaps Goals
• Alternative Architecture and their limitations

5
IDMaps Goals

• Separation of Functions
• Distance Metrics
• Accuracy of the Distance Information
• Timeliness of the Distance Information
• Scope of the Distance Information

6
IDMaps Advantages

• More Efficient --- O(N) vs O(N2)
• Not only measure regions traversed
• Adapt well to topological changes
• --- small change to distance information
  database
• Low administrative cost and human effort
• Avoid security risk --- no ICMP

7
3. IDMaps Architecture

• Address three questions

What form does the distance information take?
What are IDMaps component? How should the
distance information be disseminated?
8
Various Forms of Distance Information
An AP is a consecutive address range of IP
addresses within which all hosts with assigned
addresses are equidistant to the rest of the
Internet.
The AS is the unit of path information carried by
the BGP inter domain routing protocol.
9
Various Forms of Distance Information (Cont)
10
Three main components

• Aps
• Tracers
• Virtual Links (VLs)
• between tracers between Tracers and
  APs

11
An assumption Triangulation
a-cltbltac ? Feasible to estimate distance?
12
Deployment of IDMaps
Tracer Placement Virtual Link Distance
Information Dissemination
13
Tracer Placement

• Principle for Tracer placement minimizing the
  maximum distance between an AP and its nearest
  Tracer.
• Two variations
• 1. Given maximal center-node distance,
  require to find the
• minimum number of centers.
• 2. Given number of centers, decide the
  locations of the
• centers.

14
Tracer Placement (Cont)

• Two graph theoretic approaches
• K HST
• K Center
• They are based on a known network
  topologies.
• Tracer Heuristics

15
Virtual Links

• Tracer Tracer Virtual Links
• Not necessary to list all B2 tracer
  tracer
• distances

16
Virtual Links (Cont)

• Tracer AP Virtual Links
• A dedicated tracer?
• More than one tracer?
• If an AP has more than one path to the rest
  of the Internet, having a single Tracer tracing
  to that AP could result in inaccurate distance
  estimates between this AP and hosts that are not
  sharing paths with the Tracer.

C in AP1 will be directed to mirror M1 in AP3
instead of M2 in AP2 Had tracer T2 also traced to
AP1, the client would have been directed to M2
17
Conclusion

• Services using IDMaps SONAR and HOPs
• Goals of IDMaps
• Advantages of IDMaps
• Architecture of IDMaps Tracer, AP, Virtual Link
• Process of implementation

18
Questions and Comments

• Thanks!