In the upstream direction, the received IPv6 fragments are artifacts of the IPv4 packets being fragmented on the CP side, before they are translated into IPv6. No flow caching is performed in the upstream direction. The BR performs an anti-spoof for each fragment and if the anti-spoof is successful, the fragment is translated to IPv4. Figure: Fragmentation in the upstream direction shows the upstream fragmentation scenario.
Figure: Fragmentation in the upstream direction
