Link Failures in IP Networks:
Download
1 / 27

Yashar Ganjali Sprint Advanced Technology Lab. August 5, 2003 - PowerPoint PPT Presentation


  • 83 Views
  • Uploaded on
  • Presentation posted in: General

Link Failures in IP Networks:. A Closer Look. Yashar Ganjali Sprint Advanced Technology Lab. August 5, 2003. Previous Work. Link Failures. Maintenance. Unplanned. 70 % of Unplanned. Shared: Router Related, Optical Related, …. Individual Link Failures. Our Work.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha

Download Presentation

Yashar Ganjali Sprint Advanced Technology Lab. August 5, 2003

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Link Failures in IP Networks:

A Closer Look

Yashar Ganjali

Sprint Advanced Technology Lab.

August 5, 2003


Previous Work

Link Failures

Maintenance

Unplanned

70 % of

Unplanned

Shared: Router Related, Optical Related, …

Individual Link Failures

Link Failures in IP Networks: A Closer Look


Our Work

  • Goal: gaining a deeper understanding of the causes & characteristics of link failures

  • How:

    • Using SONET alarm logs

    • Focusing on high failure links/periods

Link Failures in IP Networks: A Closer Look


IS-IS Failures, Feb. 2003

Link Failures in IP Networks: A Closer Look


Number of Failures per Day

Link Failures in IP Networks: A Closer Look


Zoom In

Link Failures in IP Networks: A Closer Look


Zoom In (Cont’d)

Link Failures in IP Networks: A Closer Look


High Failure Periods

  • Periods with a large number of failures (HNP)

  • Periods in which a large percentage of links are down (HDP)

Link Failures in IP Networks: A Closer Look


Number vs. Duration of Failures

Link Failures in IP Networks: A Closer Look


High Failure Periods

Link Failures in IP Networks: A Closer Look


Periods with High Number of Failures

Link Failures in IP Networks: A Closer Look


High Failure Periods (Cont’d)

  • We can also classify high failure periods based on spatial distribution of the links failing in those periods.

Link Failures in IP Networks: A Closer Look


Spatial DistributionJune 17, 2003

Link Failures in IP Networks: A Closer Look


Spatial DistributionFeb. 26, 2003

Link Failures in IP Networks: A Closer Look


Links with High Duration of Failures

Link Failures in IP Networks: A Closer Look


Links with High Number of Failures

Link Failures in IP Networks: A Closer Look


Matching IS-IS Failures with SONET alarms (SLOS)

Link Failures in IP Networks: A Closer Look


Preliminary Results

  • About 58% of all failures match with a SLOS alarm.

  • High Failure Links have a higher correlation with SLOS alarms (85%)

  • Router Related Failures show much less correlation than other classes (0-29%).

  • Periods with high number of failures show more correlation than periods with high duration of failures.

Link Failures in IP Networks: A Closer Look


Unmatched SLOS alarms

Link Failures in IP Networks: A Closer Look


Matching SLOS alarms

  • Problem: A large percentage (45%) of SLOS alarms do not correspond to any IS-IS failures

  • Solution: Remove links which are not up or links which go down for ever

  • Result: Less than 2% of SLOS alarms do not correspond to any IS-IS failures

Link Failures in IP Networks: A Closer Look


Matching IS-IS Failures & SONET alarms

Link Failures in IP Networks: A Closer Look


Unmatched SLOS alarms(considering removed links)

Link Failures in IP Networks: A Closer Look


Unmatched SLOS alarms

  • Spread over time

  • Almost half of them have a matching alarm (SLOS <-> SLOS cleared)

  • Minimum time between SLOS and SLOS cleared is 9 seconds.

  • More investigation???

Link Failures in IP Networks: A Closer Look


Research Direction

  • High Failure Periods: Study cascading effects, spatial distribution of failures

  • High Failure Links: Predicting future failures based on passed ones.

  • Network Availability: How do failures affect network availability?

  • ???

Link Failures in IP Networks: A Closer Look


You always pass failures on the way to success!

Thank you!

Link Failures in IP Networks: A Closer Look


Spatial-Temporal Correlation of Failures

Link Failures in IP Networks: A Closer Look


Spatial-Temporal Correlation of Failures

Link Failures in IP Networks: A Closer Look


ad
  • Login