If the Length/Type=07100 of an Ethernet data frame, which of the following options may the data frame be sent from? (Multiple choice)

Question

Options

• ASwitch Trunk type ports
• BSwitch Access type of port
• CSerial interface of the router
• DSwitch Hybrid type of port

• A
  83% (45)
• B
  4% (2)
• C
  13% (7)

Explanation

A Length/Type value of 0x8100 (the question's "07100" refers to this IEEE 802.1Q EtherType) identifies a VLAN-tagged Ethernet frame. Only port types that are permitted to send tagged frames can originate such a frame.

Why A and D are correct: Trunk ports (A) send 802.1Q-tagged frames for all VLANs except their native VLAN, and Hybrid ports (D) are a flexible port type (common in Huawei/H3C equipment) that can send both tagged and untagged frames-so both can produce frames carrying the 0x8100 tag.

Why B is wrong: Access ports always strip the 802.1Q tag before forwarding a frame to an end device, so a tagged frame with EtherType 0x8100 never exits an Access port.

Why C is wrong: A router's serial interface uses WAN encapsulation protocols such as PPP or HDLC-it does not transmit Ethernet frames at all, tagged or otherwise.

Memory tip: Think "tags survive through Trunk and Hybrid, but Access always strips them bare, and Serial never speaks Ethernet." Any port that can send a 0x8100-tagged frame must be one that preserves VLAN tags on egress.

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