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
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
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
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TCP checksum:A mechanism that makes sure that no data is lost or corrupted during a transfer
TCP segment: A payload section of an IP datagram made up of a TCP header and a data section
TCP window: The range of sequence numbers that might be sent before an acknowledgement is required
Time-To-Live field (TTL): An 8-bit field that indicates how many router hops a datagram can traverse before it's thrown away
Total hops: The total number of devices data passes through to get from its source to its destination. Routers try to choose the shortest path, so fewest hops possible. The routing table is used to keep track of this
