The Subnetwork Access Protocol is a mechanism for multiplexing, on networks using IEEE 802.2 LLC, more protocols than can be distinguished by the 8-bit 802.2 Service Access Point fields. SNAP supports identifying protocols by EtherType field values; it also supports vendor-private protocol identifier spaces.

What protocol is used by Snapchat?

Because Snapchat uses HTTPS and TLS, the packets we were able to intercept (see section 6.3. 1) were encrypted. We then attempted to intercept and decrypt packets using Charles Proxy, Fiddler, and WireShark.

What is a snap header used for?

The SNAP header is used when the LLC protocol carries IP packets and contains the information which would otherwise have been carried in the 2-byte MAC frame type field.