Obtaining information from data items

摘要

Methods and apparatus are disclosed for obtaining and processing information from a predetermined portion of a header of a data item such as an IP packet transmitted via a communication network such as a packet network, the portion carrying a codepoint selected from a first set of codepoints each of which has a pre-defined meaning according to a first pre-defined communication protocol. The method comprises: receiving the data item; inspecting the header whereby to determine the codepoint carried by the predetermined portion thereof; identifying whether the codepoint is a member of a second set of codepoints, the second set comprising fewer possible codepoints than the first set; and in the event that the codepoint is identified as being a member of the second set, and in dependence on such an identification being made, interpreting that codepoint according to a different pre-defined communication protocol as having a different pre-defined meaning and routing the data item via the communication network via the second pre-defined communication protocol.

主权项

1. A method of obtaining and processing information from a predetermined portion of a header of a data item transmitted via a communication network, said portion carrying a codepoint which is one of a plurality of codepoints of a first set of codepoints, each codepoint of the first set of codepoints having a first pre-defined meaning according to a first pre-defined communication protocol, the method comprising:
receiving the data item, the codepoint carried by the predetermined portion of the header of the data item being one of the plurality of codepoints of the first set of codepoints having the first pre-defined meaning according to the first pre-defined communication protocol; inspecting the header of the data item whereby to determine the codepoint carried by the predetermined portion thereof; identifying, using a computer processor, whether or not the codepoint is a member of a second set of codepoints, the second set of codepoints comprising fewer possible codepoints than the first set of codepoints, each codepoint of the second set of codepoints having a second pre-defined meaning according to a second pre-defined communication protocol; in the event that the codepoint carried by the predetermined portion of the header of the data item is not identified as being a member of the second set of codepoints, interpreting the codepoint of the data item according to the first pre-defined communication protocol as having the first pre-defined meaning of the codepoint and processing the data item based on the first pre-defined meaning of the codepoint; and otherwise, in the event that the codepoint carried by the predetermined portion of the header of the data item is identified as being a member of the second set of codepoints, and in dependence on such an identification being made, interpreting the codepoint of the data item according to the second pre-defined communication protocol as having the second pre-defined meaning of the codepoint and processing the data item based on the second pre-defined meaning of the codepoint, said second communication protocol differing from said first communication protocol, and said second pre-defined meaning of the codepoint differing from said first pre-defined meaning of the codepoint; wherein processing the data item based on the first pre-defined meaning comprises forwarding the data item via the communication network based on the first pre-defined meaning, and wherein processing the data item based on the second pre-defined meaning comprises forwarding the data item via the communication network based on the second pre-defined meaning.