The present invention provides a communication device capable of providing a highly reliable service by detecting communication abnormality at a high speed. The communication device comprises a link configuring unit configuring a plurality of logical links between a opposite communication device, a segmenting unit segmenting transmission data as being associated with each of the plurality of logical links, a transmission unit transmitting the segmented data via the logical link associated with this segmented data, a receiving unit receiving the data via each of the plurality of logical links, and an abnormality detection unit judging, within a predetermined period of time since the data were received via any one of the plurality of logical links, if the data are not received via at least one of the remaining logical links, at least one logical link to be an abnormal logical link.