1 / 16

An Analysis of BGP Convergence Properties

An Analysis of BGP Convergence Properties. Introduction The BGP protocol NP completeness Routing anomalies Complexity analysis Summery. Introduction (BGP). BGP - the de-facto EGP. Policy-based path-vector protocol. nlri, next-hop, as-path, loc-pref

vadin
Télécharger la présentation

An Analysis of BGP Convergence Properties

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. An Analysis of BGP Convergence Properties • Introduction • The BGP protocol • NP completeness • Routing anomalies • Complexity analysis • Summery

  2. Introduction(BGP) • BGP - the de-facto EGP. • Policy-based path-vector protocol. • nlri, next-hop, as-path, loc-pref • Implemented with little global knowledge. • Protocol divergence. • Dynamic solution. • Static solution. Static Solution: • Programs Routing Policies Analysis • The Route Arbiter Project • Routing Policy Specification Language (RPSL). • Internet Route Registries (IRRs). • Software Tools (RAToolSet).

  3. Introduction(NP-Completeness) • Non Deterministic Turing Machine (NDTM). • NP problems class. • NP-Complete problems class. • Reductions. • ANP-Hard, ANP  ANP-Complete. • The 3-SAT problem: (xyz)(xyz)(xyz)

  4. Routing Anomalies The DISAGREE System • AS 1 prefers route 1-2-0. • AS 2 prefers route 2-1-0.

  5. Routing Anomalies

  6. Routing Anomalies The BAD GADGET System • All AS want to reach destination d in AS 0. • Each AS prefers the counter-clockwise path of length 2.

  7. Routing Anomalies The BAD GADGET System

  8. Routing Anomalies The BAD GADGET System • All AS 2 export rules: • nlri = d  loc-pref = 1 • AS 2 import(2<-1) rules: • (nlri = d  as-path = [3,0])  loc-pref = 2 • nlri = d  loc-pref = 1 • AS 2 import(2<-3) rules: • nlri = d  loc-pref = 1

  9. Complexity Analysis The ASSIGN System An example of a 3-SAT problem: (xyz)(xyz)(xyz)

  10. Complexity Analysis The ASSIGN System X=True, Y=False, Z=False

  11. Complexity Analysis REACHABILITY (single destination)

  12. (xyz)(xyz)(xyz) C2 import(C2C1) rule: • nlri = d  (x  as-path  y  as-path  z  as-path)  loc-pref = 1

  13. Complexity Analysis ASYMMETRY

  14. Complexity Analysis SOLVABILITY (single destination)

  15. Complexity Analysis Relevant Routing Issues • REACHABILITY. • ASYMMETRY. • SOLVABILITY. • TRAPPED. • K-ROBUST. • UNIQUE.

  16. Summery Static Analysis approach problems: • Routing policies are not shared. • Complexity results  A need to rely on heuristics analysis rather than on exact analysis.

More Related