What are the strengths of trunk?
trunk is a feature of L2, with strengths as follows:
1. Increasing bandwidth: The increasing of bandwidth is not accumulation simply. For one packet with the same source and destination IP, it could only be forwarded over one link of the multiple bound. That is to say, the bandwidth provided for the stream is only the bandwidth of one link. For the stream of multiple source-destination combinations, trunk could take effect to increase the bandwidth.
2. Improving the reliability of link: Once one link fails, it will not influence the whole trunk, and the traffic will switch over to the available ones, improving the reliability of traffic over the trunk.
3. Load balance: If the source IP differs to the destination IP, traffic could go over different links. Hash for load balance is to sum up source and destination IP (MAC), and then the remainder over the number of links bound. This could ensure the order of packet.