TCP admission control
AssigneeNortel Networks Limited
InventorsAlan Stanley John Chapman, Hsiang-Tsung Kung
Life of this patent
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Abstract
Congestion at a network node can be aggravated by having too many TCP connections. A simple method of avoiding the bad effects of too many TCP connections is to limit the number of connections. Limiting the number of connections is achieved by an admission control which delays or even discards the connection set-up packets. TCP traffic flows are monitored to generate packet loss characteristics and when a certain condition is met, a connection request queue is disabled.
Claims20
In a packet data network for multimedia traffic having one or more nodes in which network one or more packets are discarded to control congestion;
- a method of performing admission control to TCP traffic flows comprising steps of;
- storing all TCP connection setup packets in a connection request queue;
- monitoring packets of all active TCP traffic flows according to their port numbers and sequence numbers;
- recording the count of either resent or discarded packets for any TCP traffic flows;
- building a history table containing the history of the sequence numbers, port numbers, and the count of either resent or discarded packets;
- computing a packet loss characteristic using the contents of the history table;
- and
- deciding enabling or disabling the connection request queue based on the packet loss characteristic with respect to a predefined pattern.
A TCP admission control apparatus for controlling congestion of a data network, comprising:
- a TCP output buffer for inspecting all the TCP packets of an incoming traffic stream according to their port numbers and sequence numbers;
- a connection request queue for storing new connection requests;
- a history table for recording the sequence numbers, port numbers and a count of either recent or discarded packets in order to compute a packet loss characteristic;
- and
- a queue controller for enabling or disabling the connection request upon detecting the matching of the packet loss characteristic with a predefined pattern.
Dependencies are inferred from the claim text.