200-150 · Question #144
Refer to the exhibit. What type of network communication is depicted?
The correct answer is C. Ethernet II frame. The exhibit depicts an Ethernet II frame, identified by its 2-byte EtherType field that directly specifies the encapsulated upper-layer protocol.
Question
Refer to the exhibit. What type of network communication is depicted?
Exhibit
Options
- AIEEE 802.3 with LLC frame
- BIEEE 802.3 with SNAP frame
- CEthernet II frame
- DTCP packet
How the community answered
(57 responses)- A4% (2)
- B2% (1)
- C88% (50)
- D7% (4)
Why each option
The exhibit depicts an Ethernet II frame, identified by its 2-byte EtherType field that directly specifies the encapsulated upper-layer protocol.
An IEEE 802.3 with LLC frame uses a Length field followed by DSAP, SSAP, and Control bytes in the LLC header - there is no EtherType field directly identifying the upper-layer protocol.
An IEEE 802.3 with SNAP frame appends a 5-byte SNAP header after the LLC header to carry vendor and protocol type information, adding overhead absent in Ethernet II.
Ethernet II (DIX Ethernet) frames use a 2-byte Type field with values greater than 1500 (0x05DC) to identify the encapsulated protocol, such as 0x0800 for IPv4 or 0x0806 for ARP. This distinguishes it from IEEE 802.3 frames, which interpret that same 2-byte field as a length value and require a separate LLC or SNAP header to carry protocol type information.
A TCP packet is a transport-layer PDU and is not a data link layer frame type.
Concept tested: Ethernet II frame format and EtherType field identification
Source: https://www.cisco.com/c/en/us/support/docs/lan-switching/ethernet/12006-eth-serv-over-gigeth.html
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