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97-0610R1 Frame-Level Performance Management Requirements for ATM Networks

97-0610R1 Frame-Level Performance Management Requirements for ATM Networks. Suba Varadarajan, Raj Jain The Ohio State University Aditya Sehgal, Southwestern Bell Communications Contact: jain@cse.ohio-state.edu http://www.cse.ohio-state.edu/~jain/. Why do we need frame-level metrics?

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97-0610R1 Frame-Level Performance Management Requirements for ATM Networks

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  1. 97-0610R1 Frame-Level Performance Management Requirements for ATM Networks Suba Varadarajan, Raj JainThe Ohio State University Aditya Sehgal, Southwestern Bell Communications Contact: jain@cse.ohio-state.edu http://www.cse.ohio-state.edu/~jain/

  2. Why do we need frame-level metrics? • Performance Requirements for: • M4 Network Element View • M4 Network View Overview

  3. Why Frame-Level? • ATM Forum TM and signaling allow ABR/UBR users to request frame-level discard also known as early packet discard (EPD) • Depending upon the frame size, a congested switch may drop many cells due to frame discard • Current network management specs do not allow monitoring any frame-level performance information

  4. Why Frame Level (Cont)? • Many users care for frame level performance. However, cell level performance does not give any indication of frame level performance.1% Cell loss ratio  1% Frame loss ratio • Frame-level monitoring becomes more important with the introduction of GFR where frames may be dropped due to UPC/NPC

  5. What is a Frame? • Frame = AAL5 Protocol Data Unit • Frame boundary is visible even in ATM layer • Switches are designed to forward/drop complete frames. UserPayload PAD Control Length CRC-32 0-64kB 0-47 2 2 4 0 0 0 0 1 PTI bit indicates End of Frame

  6. Performance Requirements • M4 Network Element View • Cell Level Monitoring • Frame Level Monitoring • M4 Network View • Note: • All counters presented here apply only for AAL5 and only if any frame-level services offered. • All counters are optional. • Defining them allows a standard method for requesting and communicating/rejecting info

  7. Cell Level Monitoring Requirements • Retrieve current (15 minute) count of cells discarded due to frame discard • Set threshold value • Modify threshold value • Support autonomous notifications of threshold crossing by ATM Network Element • Reset cell count to zero • Retrieve history counts (32 fifteen minute counts) • Mark defective data as ‘suspect’ and permit retrieval

  8. Frame Level Monitoring Requirements • Retrieve current (15 minute) counts of: • a) Frames received on each connection • b) Frames successfully passed on each connection • c) Frames discarded due to UPC/NPC disagreements • d) Frames discarded due to congestion • e) Frames passed successfully after UPC/NPC Other discarded frames can be calculated

  9. Frame Counts b a Passed Received e Queue UPC/NPC Other Other UPC/NPCDisagreements Congestion d c

  10. Frame Level (Cont) • Set threshold values for • a) Discarded frames due to UPC/NPC disagreements • b) Discarded frames due to congestion • Modify threshold values for a) and b) above • Provide autonomous notifications of threshold crossing by ATM Network Element • Reset all counts to zero • Retrieve history counts (32 fifteen minute counts) • Mark defective data as ‘suspect’ and permit retrieval

  11. M4 Network View • Support management requests for: • Performance information about entire network • Performance information about specific part of the sub-network

  12. Summary • It is important that performance management include frame level metrics • Addition of cell count and frame counts for M4 Network Element View • M4 Network View requirements

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