Improved Fast Rerouting Using Postprocessing
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Citations
Distributed Consistent Network Updates in SDNs: Local Verification for Global Guarantees
On the Price of Locality in Static Fast Rerouting
Improved Fast Rerouting Using Postprocessing
The Hazard Value: A Quantitative Network Connectivity Measure Accounting for Failures
On the Price of Locality in Static Fast Rerouting
References
Online Computation and Competitive Analysis
A highly adaptive distributed routing algorithm for mobile wireless networks
The Internet Topology Zoo
A survey of gossiping and broadcasting in communication networks
Understanding network failures in data centers: measurement, analysis, and implications
Related Papers (5)
Frequently Asked Questions (14)
Q2. What have the authors stated for future works in "Improved fast rerouting using postprocessing" ?
The authors understand their work as the first step and believe that it opens several interesting avenues for future research. In particular, it will be interesting to study alternative postprocessing algorithms, and derive formal performance guarantees for them. It would also be interesting to study further use cases for their framework, beyond the ones given in this paper, e. g., for SRLGs combined with load and stretch.
Q3. What is the effect of optimizing for low load?
For low load some flows must take detours, so in general optimizing for low load leads to higher stretch, as the authors will see in their next experiments.
Q4. What is the way to analyze arborescences?
The existence of a valid circular routing scheme based on k arc-disjoint spanning arborescences in a given network graph containing a known set of failed links can also be analyzed with the aid of Integer Linear Programming (ILP) tools.
Q5. What is the first group of constraints?
The first group of constraints (1: Arc in one tree) guarantees that each arc in the network graph belongs to at most one of k arc-disjoint spanning arborescences covering the graph.
Q6. What is the motivation behind this paper?
This paper was motivated by the computational challenges involved in computing network decompositions which do not only provide basic connectivity but also account for the quality of routes after failures.
Q7. What are the main drawbacks of static fast rerouting algorithms in the data plane?
The authors in this paper are interested in static fast rerouting algorithms in the data plane, which rely on precomputed failover rules and do not require packet header rewriting.
Q8. How many failures are there in Greedy arborescences?
Even under a high number of failures (e.g. 40), the median of routing failures is 0 in both optimized and unoptimized arborescences, only the 10% worst unoptimized arborescences seem to raise to a low 5% failure rate.
Q9. What is the effect of stretch optimization on the routing failure rate?
One can first observe (top) that this optimization has an impact on the routing failure rate: before optimizing, some packets do not reach their destination, but after swapping, the failure rate is 0.
Q10. What is the objective of swapping edges?
Figure 8 (right) presents the results of swapping edges with the objective of increasing the number of independent paths from all nodes in all arborescence pairs.
Q11. How many arborescences can be swapped before an improvement of the objective function is required?
the authors note that their algorithmic framework can also be generalized to swap multiple (i.e., more than two) arcs before an improvement of the objective function is required, even from multiple nodes at once.
Q12. What is the shortest path between the source and the root node?
to be able to minimize the maximum path stretch among all user demands d in the network graph containing failed links (arcs belonging to the set F ), the authors first introduce additional virtual unit flows to find the shortest paths between the source nodes sd and the root node r, and then, the authors determine the maximum path stretch based on the difference in length between the actually used paths (circular routing) and the reference paths (the shortest paths avoiding the failed links).
Q13. What is the problem with rewriting packet headers?
The problem is particularly challenging in scenarios where packet headers cannot be used to carry meta-information about encountered failures: such header rewriting is often undesired and introduces overhead (related to header rewriting itself, but also in terms of additional rules required at the routers to process such information).
Q14. Why are there no additional information about failure scenarios and failover objectives?
In particular, the authors are motivated by the observation that in practice, additional information about failure scenarios and failover objectives may be available, e.g., about shared risk link groups [11], [12], [13] or about critical flows for which it is important to be routed along short paths, even after failures.