Connected: An Internet Encyclopedia
Congestion

Up: Connected: An Internet Encyclopedia
Up: Topics
Up: Concepts
Prev: Bridging
Next: Cryptography

Congestion

Congestion Congestion is the Internet's ugly little secret. Nobody knows where it will strike, or when, but one thing is for sure - it's out there. Congestion in the global Internet is more the norm than the exception, and few people have any real control or understanding of it. Many different organizations are involved, and their desire for security seriously hampers any attempt to collect meaningful data.

For mid-sized networks under a single authority, where the engineer controls most or all of the routers and can monitor the network at any point, at least an attempt can be made to isolate performance problems. Traffic statistics gathered with tools like SNMP can identify major bottlenecks, but are not well suited for detailed analysis. Packet traces are invaluable, but understanding them can be time consuming. Faced with these obstacles, many organizations opt to "throw bandwidth" at their performance problems, and this should seriously be considered as a faster and often cheaper solution than picking through every packet that comes over the wire.

A good start for the engineer interested in performance problems is the literature. Nagle's RFC 896, examining congestion problems in 1984, coined the term congestion collapse, referring to a stable condition where a network becomes flooded with retransmissions. More recently, Van Jacobson's RFC 1323 discusses possible problems with TCP round-trip-time estimates.


Next: Cryptography

Connected: An Internet Encyclopedia
Congestion