Subnetwork Access Protocol (SNAP)
Definition - What does Subnetwork Access Protocol (SNAP) mean?
Techopedia explains Subnetwork Access Protocol (SNAP)
The mapping of 32-bit Internet addresses to 48-bit or 16-bit IEEE 802 addresses is accomplished through the dynamic discovery method of Address Resolution Protocol (ARP). IEEE 802 networks can have 48-bit or 16-bit physical addresses. The SNAP enables the effective use of either address size inside a specific IEEE 802 network.
The LLC header is three octets long, while the SNAP header is five octets long. So, a combination of LLC and SNAP headers is overall eight octets long. On Ethernet, this minimizes the available payload size for protocols.