A network security appliance running a Syslog service generates an alert log message that must be sent to a remote monitoring server over UDP port 514. In what chronological order does the local host network stack encapsulate the log data from creation to transmission onto the wire?
- 1The Syslog service formats the alert message into an application payload.
- 2The UDP protocol encapsulates the application payload with source and destination port numbers to form a datagram.
- 3The IP protocol appends source and destination IP addresses to create an IP packet.
- 4The Ethernet protocol wraps the IP packet with source and destination MAC addresses and a Frame Check Sequence (FCS) trailer to create a frame.
- 5The Network Interface Card (NIC) converts the digital frame into electrical signals and transmits them onto the physical copper cabling.
Answer
The correct order of encapsulation begins with Application payload creation, followed by Transport layer UDP datagram encapsulation, Network layer IP packet creation, Data Link layer Ethernet framing with MAC addresses and FCS, and finally Physical layer bit conversion to electrical signals.
Outbound encapsulation follows the OSI model from top to bottom (Layer 7 down to Layer 1). The process begins when the Syslog process creates the application payload. Next, the Transport layer adds UDP port headers to create a datagram. Then, the Network layer appends IP addresses to form a packet. After that, the Data Link layer appends MAC addresses and an FCS trailer to construct an Ethernet frame. Finally, the Physical layer encodes the frame into physical signals to send across the network wire.
Step-by-Step Solution
Key Concept
Top-down OSI model outbound data encapsulation sequence (Data -> Datagram/Segment -> Packet -> Frame -> Bits).