A method performed by a network node in a communication network comprising a plurality of communication devices, for finding temporally connected connection patterns of the communication devices in the network, wherein a temporally connected connection pattern is a connection pattern based on temporal motifs and the temporally connected connection patterns are reconnection patterns after, or disconnection patterns due to, an outage in the communication network, the method characterized by: identifying signalling between the communication devices during a predefined time duration to form a main communication graph in which the plurality of communication devices are nodes; partitioning the main communication graph for a time period comprised in said time duration to capture temporally connected signalling between some of the communication devices as illustrated in the main communication graph in a partitioned communication graph; forming at least one subgraph from the partitioned communication graph, comprising m nodes corresponding to m communication devices of said some of the communication devices; constructing a binary vector of the subgraph, wherein the binary vector is obtained by performing a time-wise OR-operation on a binary matrix representing temporal communication among the nodes, over the time period divided into a plurality of sampling periods corresponding to components in the vector such that, for each component in the vector, the component value is set to "1" if, in accordance with the subgraph, signalling occurs between at least two of the m communication devices during the sampling period corresponding to the component, and the component value is otherwise set to "0"; and testing whether the signalling between the different m communication devices used for constructing the binary vector is temporally connected by checking that the number of consecutive "0" component(s), if any, between any two "1" components is less than a predefined time difference. identifying signalling between the communication devices during a predefined time duration to form a main communication graph in which the plurality of communication devices are nodes; partitioning the main communication graph for a time period comprised in said time duration to capture temporally connected signalling between some of the communication devices as illustrated in the main communication graph in a partitioned communication graph; forming at least one subgraph from the partitioned communication graph, comprising m nodes corresponding to m communication devices of said some of the communication devices; constructing a binary vector of the subgraph, wherein the binary vector is obtained by performing a time-wise OR-operation on a binary matrix representing temporal communication among the nodes, over the time period divided into a plurality of sampling periods corresponding to components in the vector such that, for each component in the vector, the component value is set to "1" if, in accordance with the subgraph, signalling occurs between at least two of the m communication devices during the sampling period corresponding to the component, and the component value is otherwise set to "0"; and testing whether the signalling between the different m communication devices used for constructing the binary vector is temporally connected by checking that the number of consecutive "0" component(s), if any, between any two "1" components is less than a predefined time difference.