Store-and-Forward

Store-and-Forward is used to describe a functionality where a switch receives a complete packet, stores it, and only then forwards it.

since the switch make forwarding decisions based on the destination address which is at the header of the packet, the switch can make the forwarding decision before receiving the complete packet, this process is called cut-through, the switch forwards part of the packet before receiving the complete packet.

Cut-through allows lower latency and saves buffer space, but if an error occurred in the packet while utilizing cut-through, the packet will be forwarded with an error, alternatively, utilizing store-and-forward allows the switch to drop erroneous packets.

The standard implementation of forwarding mode is for the entire switch; either all ports on a switch are in store-and-forward mode or all ports on a switch are in cut-through mode. NVIDIA implements forwarding mode per egress port, which is a more flexible method and vital in cases where a switch is connected to both a storage device and a compute server among other setups.

For more information about this feature and its potential applications, please refer to the following community post:

• Switch Forwarding: "Store and Forward" vs. "Cut-through"

switchmode store-and-forward

switch (config)# switchmode store-and-forward