1. Unsynchronized Triggered Multicast Diagnostic Report
September 2007
Unsynchronized Triggered Multicast Diagnostic Report
Date:
Authors:
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Nakjung Choi, Seoul National University

2. September 2007
Comment Resolution
CID When AP STA sends a triggered multicast diagnostic request having the same trigger condition to several non-AP STAs, non-AP STAs accepting the triggered multicast diagnostic request can simultaneously send multicast diagnostic reports to AP STA.
CID triggered multicast diagnostics are likely to be triggered at the same time in multiple stations, which will in turn all try to access the medium to transmit reports. This will likely cause a traffic storm
Nakjung Choi, Seoul National University

3. Background Multicast vs. Several Unicasts
September 2007
Background
Multicast vs. Several Unicasts
Successive multicast frames collide with unicast frames
A new frame to send when a QSTA’s queue is empty
Immediate access when the medium is free >= DIFS
Management frame in IEEE e MAC
The highest priority, AC_VO (small CWmin)
Nakjung Choi, Seoul National University

4. Triggered Condition is Satisfied at this time !!
September 2007
Problem Definition
If the triggered condition is satisfied, several multicast receivers may simultaneously transmit triggered multicast diagnostic reports
No backoff or backoff with very small CWmin
DIFS …
Multicast 1
Multicast n
QAP
Collision or Loss
Triggered Multicast Diagnostic Report
M-QSTA1
Triggered Multicast Diagnostic Report
M-QSTA2
Triggered Multicast Diagnostic Report
M-QSTA3
Collision !!
Triggered Condition is Satisfied at this time !!
Nakjung Choi, Seoul National University

5. Proposal (1/2) Unsynchronized Triggered Multicast Diagnostic Report
September 2007
Proposal (1/2)
Unsynchronized Triggered Multicast Diagnostic Report
When a QSTA sends a triggered multicast diagnostic report, the STA waits a randomized time before transmitting the report
On this purpose, Multicast Triggered Reporting field for a triggered multicast diagnostic request may include jitter interval, which can be determined depending on the number of multicast receivers performing the same triggered multicast diagnostic
Multicast Trigger Condition field may include jitter, which indicates jitter interval
Nakjung Choi, Seoul National University

6. Randomization Interval Multicast Triggered Reporting
September 2007
Proposal (2/2)
Randomization Interval
Measurement Duration
Multicast MAC Address
Multicast Triggered Reporting
Octets: 2 4 6 5 3
Multicast Trigger Condition
Report Timeout
Trigger Timeout
Jitter Interval (TU)
Octets: 1 1 1 2
Report Timeout Request
Jitter
Reserved
Bits: 1 7 6
Nakjung Choi, Seoul National University

7. September 2007
Straw poll
Should we prepare the normative text on Unsynchronized Triggered Multicast Diagnostic Report?
Yes:
No:
Abstain:
Nakjung Choi, Seoul National University