Download presentation

Presentation is loading. Please wait.

Published byNicholas Collins Modified over 2 years ago

1
Algorithms for computing Maximally Redundant Trees for IP/LDP Fast-Reroute draft-enyedi-rtgwg-mrt-frr-algorithm-01 Alia Atlas (Juniper Networks) Gabor Enyedi, Andras Csaszar (Ericsson) IETF 83, Paris, France

2
**Agenda Briefly about the algorithm Problem Avoid using a node**

Non-2-connected networks

3
**Agenda Briefly about the algorithm Problem Avoid using a node**

Non-2-connected networks

4
ADAG and partial order E G D Root C S B A H

5
**ADAG and partial order Almost DAG (ADAG)**

A<<B if there is a path from A to B Root is both the shortest and the greatest E G D Root C S B A H

6
**ADAG and partial order S<<E Blue path: increasing [S, E]**

Red path: decreasing [Root, S] and [E, Root] E G D Root C S B A H

7
**ADAG and partial order S>>A**

Blue path: increasing [S,Root] and [Root, A] Red path: decreasing [A, S] E G D Root C S B A H

8
**ADAG and partial order S and C are not ordered**

Blue path: [S, E] and [C, E] Red path: [A, S] and [A, C] E G D Root C S B A H

9
**Agenda Briefly about the algorithm Problem Avoid using a node**

Non-2-connected networks

10
**Three trees We have tree trees**

SPT Two MRTs There is no connection between SPT and MRTs Impossible to find a redundant pair for SPT Example: Shortest path 1 C D 10 1 Dest S No redundant pair for that! 1 10 1 B A 1

11
**Agenda Briefly about the algorithm Problem Avoid using a node**

Non-2-connected networks

12
**Total order Partial order can compare any X only with S**

We need to compare any two nodes Make a total order as well If A<<B, let A<B If A and B are not ordered select either A<B or B<A This can be done with a topological oder after converting the ADAG into a DAG Results: If A<B, either A<<B or A and B are not ordered

13
**A possible total order Numbers are written next to nodes 8 7 E G 6 D**

Root C S 4 5 3 B A H 1 2

14
**Possible cases If dst>>src, failed node F**

If S<<F<E, it may be on the BLUE path 8 7 E G 6 D Root C S 4 5 3 B Otherwise: it may be on the RED path A H 1 2

15
**Possible cases If dst<<src, failed node F**

Otherwise: it may be on the BLUE path 8 7 E G 6 D Root C S 4 5 3 If A<F<<S, it may be on the RED path B A H 1 2

16
**Possible cases If dst and src are not ordered There are four sub-paths**

If F>>src, it may be on the first part of the RED path If F and src are not ordered, and F>dest, it may be on the second part of the RED path 7 8 E G 6 D Root 4 C S 5 3 F and src are not ordered, and F<dest, it may be on the second part of BLUE path B If F<<src, it may be on the first part of the BLUE path 1 A H 2

17
**Agenda Briefly about the algorithm Problem Avoid using a node**

Non-2-connected networks

18
**Non-2-connected problem**

In this case we don’t have a single order Neither a partial order Nor a total order Convert the GADAG into an ADAG! C A Non-root block X Local root block D B

19
**Non-2-connected problem**

In this case we don’t have a single order Neither a partial order Nor a total order Convert the GADAG into an ADAG! C A X1 Non-root block Local root block X2 D B

20
Thank you!

Similar presentations

Presentation is loading. Please wait....

OK

COSC 2007 Data Structures II Chapter 14 Graphs I.

COSC 2007 Data Structures II Chapter 14 Graphs I.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on biodegradable and non biodegradable pictures Ppt online gambling addiction Ppt on society and culture Animated ppt on human digestive system Ppt on disk formatting mac Ppt on central limit theorem statistics Ppt on electricity generation from solar energy Ppt on power transmission and distribution in india Ppt on object-oriented programming interview questions Ppt on feedback amplifier