Methods, systems and apparatus are provided which prevent frame
mis-ordering in an explicitly routed network when switching from a first
path to a second path. In a first embodiment, last frame and first frame
markers are transmitted, and a receiver buffers all frames received
between receipt of the last frame marker and the first frame marker. In a
second embodiment, a last frame marker is sent to which an
acknowledgement must be received before transmitting on the second path.
In a third embodiment, only a first frame marker is sent. The receiver,
upon receipt, signals a network card for the first path to stop
forwarding frames, also buffers frames for some period. In a fourth
embodiment, the merge point node forwards frames over different paths
with unique markings so the outgoing card can distinguish them.