Question

Difficulty: EasyEncapsulation and De-encapsulation

A system administrator observes syslog messages being sent from a local host to a remote log server. As the outgoing syslog data passes down the host's protocol stack during encapsulation, which of the following actions occur? (Select TWO.)

  1. The Transport layer encapsulates the syslog payload into a segment or datagram by adding transport port headers.Answer
  2. The Network layer encapsulates the transport data unit into a packet by adding source and destination IP addresses.Answer
  3. C
    The Data Link layer attaches port numbers directly to the physical bitstream while stripping the IP header.
  4. D
    The Transport layer appends a Frame Check Sequence (FCS) trailer to verify physical media signals.

Answer

During outbound encapsulation, the Transport layer appends transport port headers to create a segment/datagram, and the Network layer appends IP addresses to form a packet.
Outbound encapsulation works down the protocol stack. The Transport layer adds port headers to form segments or datagrams, and the Network layer adds IP headers to form packets.

Step-by-Step Solution

1
Analyze Layer 4 processing during outbound encapsulation.
Application payload (syslog data) receives a Transport layer header with source and destination ports.
Layer 4 handles process-to-process communication by prepending port addresses.
2
Analyze Layer 3 processing during outbound encapsulation.
The resulting Transport datagram receives a Network layer header containing source and destination IP addresses.
Layer 3 handles host-to-host logical routing across network boundaries.

Key Concept

Outbound Encapsulation Sequence and Protocol Data Units
Estimated Time:45s
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