25. An apparatus, comprising: one or more network access ports configured to receive at least a first data stream from a first device and a second data stream from a second device, wherein the first data stream and the second data stream each include one or more sequenced data items; one or more processors configured to: construct a first grammar associated with the first device and a second grammar associated with the second device, wherein the first grammar and the second grammar each comprise a symbol sequence that re-expresses the one or more sequenced data items in the respective data streams received from the first device and the second device; calculate one or more distance metrics that quantify a similarity between the first grammar and the second grammar according to a comparison between one or more rules that represent a repeated pattern in the symbol sequence associated with the first grammar and one or more rules that represent a repeated pattern in the symbol sequence associated with the second grammar; and determine a relationship between the first device and the second device according to the one or more distance metrics.
25. An apparatus, comprising: one or more network access ports configured to receive at least a first data stream from a first device and a second data stream from a second device, wherein the first data stream and the second data stream each include one or more sequenced data items; one or more processors configured to: construct a first grammar associated with the first device and a second grammar associated with the second device, wherein the first grammar and the second grammar each comprise a symbol sequence that re-expresses the one or more sequenced data items in the respective data streams received from the first device and the second device; calculate one or more distance metrics that quantify a similarity between the first grammar and the second grammar according to a comparison between one or more rules that represent a repeated pattern in the symbol sequence associated with the first grammar and one or more rules that represent a repeated pattern in the symbol sequence associated with the second grammar; and determine a relationship between the first device and the second device according to the one or more distance metrics. 26. The apparatus recited in claim 25 , wherein the one or more distance metrics include at least one distance metric that quantifies a syntactic similarity between the first grammar and the second grammar.