Abstract: Networks (1) comprising primary spanning trees (11-18) for guiding information are provided with failure detectors (42) for detecting link or node (interface) failures in the primary spanning trees (11-18) and with backup spanning trees (21-28) for, in response to failure detection results, guiding the information via at least a part of the backup spanning tree (21-28), to respond quickly to such failures. The information comprises tags mapped to the primary spanning trees (11-18). The networks (1) or nodes (2-10) further comprise tag modifiers (43) for, in response to failure detection results, modifying the tags, with modified tags being mapped to the backup spanning trees (21-28) to inform other nodes (2-10) that the backup spanning trees (21-28) are to be used. The tag comprises a virtual local area network tag comprising at least one modifiable bit for indicating the spanning tree (11-18,21-28) to be used.