packet fragmentation

1. In IP transmission load balancing or load sharing, where does reassemby of the packets occur? The destination's serial network interfaces, or the destination host?

2. If any fragment is missing, the entire sequence of fragments will need to be retransmitted. Is this done at the transport level from the inbound interface or the host/destination?

Thanks.
Said

1. At the destination serial network interface

2. Didn't get you

2. At the originating host. In the meantime, an ICMP "packet dropped" message is sent back to the originating host.