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Book contents
- Frontmatter
- Contents
- Acknowledgments
- 1 Introduction
- 2 Background and context
- I Network monitoring and management
- II Network design and traffic engineering
- 6 Principles of network design and traffic engineering
- 7 Topology design resilient to long-lived failures
- 8 Achieving topology resilience using multiple-parallel links
- 9 Performance enhancement and resilience to short-lived failures via routing optimization
- 10 Measuring the shared fate of IGP engineering: considerations and take-away
- 11 Capacity planning
- III From bits to services
- Appendix A How to link original and measured flow characteristics when packet sampling is used: bytes, packets and flows
- Appendix B Application-specific payload bit strings
- Appendix C BLINC implementation details
- Appendix D Validation of direction-conforming rule
- References
- Index
10 - Measuring the shared fate of IGP engineering: considerations and take-away
from II - Network design and traffic engineering
Published online by Cambridge University Press: 05 September 2012
- Frontmatter
- Contents
- Acknowledgments
- 1 Introduction
- 2 Background and context
- I Network monitoring and management
- II Network design and traffic engineering
- 6 Principles of network design and traffic engineering
- 7 Topology design resilient to long-lived failures
- 8 Achieving topology resilience using multiple-parallel links
- 9 Performance enhancement and resilience to short-lived failures via routing optimization
- 10 Measuring the shared fate of IGP engineering: considerations and take-away
- 11 Capacity planning
- III From bits to services
- Appendix A How to link original and measured flow characteristics when packet sampling is used: bytes, packets and flows
- Appendix B Application-specific payload bit strings
- Appendix C BLINC implementation details
- Appendix D Validation of direction-conforming rule
- References
- Index
Summary
The Internet is made of many separate routing domains called Autonomous Systems (ASs), each of which runs an IGP such as IS–IS or OSPF. The IGP handles routes to destinations within the AS, but does not calculate routes beyond the AS boundary. Internet Gateway Protocol engineering (or traffic engineering or IGP optimization) is the tuning of local IS–IS or OSPF metrics to improve performance within the AS. Today, IGP engineering is an ad-hoc process where metric tuning is performed by each AS in isolation. That is, each AS optimizes paths within its local network for traffic traversing it without coordinating these changes with neighboring ASs. The primary assumption behind such an assertion is that there is sufficient separation between intra-domain and inter-domain routing.
Beyond the AS boundary, the choice of AS hops is determined by the BGP,; BGP engineering is a less developed and less understood process compared to IGP engineering. In addition to whether there is a physical link between two ASs over which routes and traffic can flow, there are several BGP policies that determine which inter-domain paths are exposed to a neighboring AS. Business peering policies can directly translate into which routes are exported to each AS. After all these policies are applied, the remaining feasible paths are subjected to the “hot-potato” routing policy. Hot-potato routing occurs when there are multiple egress points to reach a destination.
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- Chapter
- Information
- Design, Measurement and Management of Large-Scale IP NetworksBridging the Gap Between Theory and Practice, pp. 201 - 216Publisher: Cambridge University PressPrint publication year: 2008