Expected from

1
How not to kill wireless
But now add more callers..

• 1. Prioritise (no backoff) and schedule outgoing
  VoIP

Note no collisions
VoIP traffic

• 2. Access point aggregates incoming VoIP, saving
  overhead

Web traffic
packet
Time
No changes to non-VoIP computers at all
Less airtime for e.g. web users
More airtime wasted on collisions and backoff
Current impact on TCP
Reduced impact on TCP
WiFi contention procedure
packet
Expected (from

• To transmit data
• Wait for everyone to be quiet
• Wait a bit more (back off)
• Transmit
• In case of a collision, back off more, then retry

Our solution
size of VoIP packets)
(emulated)
Measured (802.11b)
Our solution (calculated)
Inefficiency of VoIP
Current (measured)
TCP capacity destroyed!