Transporting data: one-to-many
 
 
- Separate TCP connection per user
- 
- Does not scale well
- server $ and bandwidth $ constant per user
 
- Often no back channel
 
- Same UDP stream to every user
- 
- Carousel over data
- Takes a long time to complete
 
- Broadcast / IP Multicast
- 
- Unreliable
- Retransmission-based reliability problematic