Decongestion Control

1
Decongestion Control

• Offense by
• James Gross
• Amit Mondal

2
Basic Idea

• Approximate fairness through differential
  droppings Pan et al. 03
• Per-flow?
• Sending rate is not sensitive to packet losses
• Packet losses are compensated by coding

3
Design Problem

• Assumption
• Bottlenecks are always at the edge
• Access link
• Neglect the case of multiple bottlenecks
• Leads to network working in reduced efficiency
  because of dead packets consuming network
  resources

4
Contd

• Interaction with Overlay routing, Traffic
  Engineering etc?
• Overhead of coding?
• Packet duplication!
• Isnt it simply waste of network resources?
• How about Control Packets in the network like
  SYN/ FIN/RST etc?

5
Contd

• Network is always congested. How do you diagnose
  the network?
• Traceroute, Ping?
• DNS over UDP?
• How about BGP Sessions?
• BGP is erratic in presence of congestion

6
Contd

• Misconfiguration at access router compromises
  global fairness

7
Deployment Issue

• Compatibility/Interaction with other congestion
  protocols like TCP, UDP etc.
• Incremental deployability?
• Both end-users and network switches need to be
  modified! Huge deployment overhead!