Overload protection for SIP servers

• US 7,522,581 B2
• Filed: 08/01/2006
• Issued: 04/21/2009
• Est. Priority Date: 08/01/2006
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Wright, Charles P., Tracey, John Michael, Acharya, Arup, Wang, Xiping, Xiao, Zhen, Nahum, Erich M.
• Primary Examiner(s): Orgad; Edan
• Assistant Examiner(s): Vu; Hoang-Chuong Q
• Application Number:
  US11/497,948
• Publication Number:
  US 20080031258A1
• Time in Patent Office: 994 Days
• Field of Search: 370/395.42, 370/395.43, 370352-356, 709/223, 709227-229
• US Class Current: 370/352
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/19 at layers above the network layer network arrangements for networked applications for scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 47/801 Real time traffic
• CPC Class Codes: H04L 47/821 Prioritising resource allocation or reservation requests
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 65/1046 Call controllers; Call servers
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers

Abstract

A method for operating a server having a maximum capacity for servicing requests comprises the following steps: receiving a plurality of requests; classifying each request according to a value; determining a priority for handling the request according to the value, such that requests with higher values are assigned higher priorities; placing each request in one of multiple queues according to its priority value; and dropping the requests with the lowest priority when the plurality of requests are received at a rate that exceeds the maximum capacity. The server operates according to a session initiation protocol.

Classifying each request comprises running a classification algorithm. The classification algorithm comprising steps of: receiving a rule set, each rule comprising headers and conditions; creating a condition table by taking a union of all conditions in the rules; creating a header table by extracting a common set of headers from the condition table; extracting the relevant headers from the header table; determining a matching rule; creating a bit vector table; selecting the matching rule according to data in the bit vector table; and applying the rule to place the message in the appropriate queue.

Claims

1. A method for operating a server a session initiation protocol (SIP) server having a maximum capacity for servicing requests, the method-comprising steps of:

a) receiving a plurality of requests for an SIP message session, wherein said plurality of requests comprise;

session initiation requests, session modification requests, and requests for binding a user to an address;

b) classifying each request according to a value, wherein said classifying step comprises;

b.1) running a classification algorithm at run time, the classification algorithm comprising steps of;

b.2) receiving a rule set, each rule comprising headers and conditions, wherein the rules with a numerically higher priority value have precedence over the rules with a numerically lower priority value and wherein a first matching rule will be applied for the rules with a same priority value, and the rules are sorted in decreasing order of priority such that a matching process can be stopped after a first matching rule is found; and

wherein headers are classified as one of;

simple headers, pseudo-headers, and derived headers, and wherein, in conjunction with user-defined derived headers, the user is allowed to specify complex data types comprising structures and complex data variables associated with arrays, pointers, and scalars;

b.3) creating a condition table by taking a union of all conditions in the rules;

b.4) creating a header table by extracting a common set of headers from the condition table;

b.5) extracting the relevant headers from the header table;

b.6) determining a matching rule;

b.7) creating a bit vector table;

b.8) selecting the matching rule according to data in the bit vector table; and

b.9) applying the matching rule to place the request in an appropriate queue from among a plurality of queues comprising a high priority queue, a medium priority queue, and a low priority queue; and

wherein said value of the request is based upon a plurality of message types, the message types comprising;

register message;

presence subscription and notification;

bye messages;

specific destinations;

source of the message;

whether the message belongs to a session-in-progress;

whether the message belongs to a new session setup; and

within a message, retransmission of a message vs. the first instance the message is being sent;

c) determining a priority for handling the request according to the value, such that requests with higher values are assigned higher priorities;

d) placing each request in one of multiple queues according to its priority value; and

e) dropping the requests with the lowest priority when the plurality of requests are received at a rate that exceeds the maximum capacity.