Service type field: A eight bit field that can be used to specify details about quality of service or QoS technologies
Session layer: The network layer responsible for facilitating the communication between actual applications and the transport layer
Simplex communication: A form of data communication that only goes in one direction across a cable
Socket: The instantiation of an endpoint in a potential TCP connection
Source MAC address:The hardware address of the device that sent the ethernet frame or data packet. In the data packet it follows the destination MAC address
Source port: A high numbered port chosen from a special section of ports known as ephemeral ports
SRV record: A service record used to define the location of various specific services
Start Frame Delimiter (SFD): The last byte in the preamble, that signals to a receiving device that the preamble is over and that the actual frame contents will now follow
Start of authority: A declaration of the zone and the name of the name server that is authoritative for it
Static IP address: An IP address that must be manually configured on a node
Subnet mask: 32-bit numbers that are normally written as four octets of decimal numbers
Subnetting: The process of taking a large network and splitting it up into many individual smaller sub networks or subnets
SYN flag: One of the TCP flags. SYN stands for synchronize. This flag is used when first establishing a TCP connection and make sure the receiving end knows to examine the sequence number field
SYN_RECEIVED: A TCP socket state that means that a socket previously in a listener state, has received a synchronization request and sent a SYN_ACK back
SYN_SENT: A TCP socket state that means that a synchronization request has been sent, but the connection hasn't been established yet
T
TCP checksum: A mechanism that makes sure that no data is lost or corrupted during a transfer
