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  1. Which transmission mode is supported by both HDLC and SDLC?
    A. Asynchronous Balanced Mode (ABM)
    B. Asynchronous Response Mode (ARM)
    C. Normal Balanced Mode (NBM)
    D. Normal Response Mode (NRM)

Correct Answer and Explanation: D. Answer D is correct; both HDLC and SDLC support Normal Response Mode (NRM), where secondary nodes can transmit when given permission by the primary.

Incorrect Answers and Explanations: A, B, and C. Answers A, B, and C are incorrect. HDLC supports Asynchronous Balanced Mode (ABM) and Asynchronous Response Mode (ARM), while SDLC does not. There is no such mode as Normal Balanced Mode (NBM).

  1. What is the most secure type of EAP?
    A. EAP-TLS
    B. EAP-TTLS
    C. LEAP
    D. PEAP

Correct Answer and Explanation: A. Answer A is correct; EAP-TLS is the most secure (and costly) form of EAP because it requires both server- and client-side certificates.

Incorrect Answers and Explanations: B, C, and D. Answers B, C, and D are incorrect. EAP-TTLS and PEAP are similar and don't require client-side certificates. LEAP is a Cisco-proprietary protocol that does not require client-side certificates, and also has fundamental security weaknesses.

  1. What WAN Protocol has no error recovery, relying on higher-level protocols to provide reliability?
    A. ATM
    B. Frame Relay
    C. SMDS
    D. X.25

Correct Answer and Explanation: B. Answer B is correct; Frame Relay is a packet switched Layer 2 WAN protocol that features no error recovery.

Incorrect Answers and Explanations: A, C, and D. Answers A, C, and D are incorrect. ATM and SMDS are cell-based WAN protocols that provide error correction. X.25 is a packet switched protocol similar to Frame Relay, but X.25 features error recovery.

  1. What frequencies are used by ZigBee in the United States?
    A. 784 MHz and 2.4 MHz
    B. 868 MHz and 2.4 MHz
    C. 915 MHz and 2.4 MHz
    D. 2.4 MHz and 6 MHz

Correct Answer and Explanation: C. Answer C is correct; ZigBee uses 915 MHz and 2.4 MHz in the United States.

Incorrect Answers and Explanations: A, B, and D. Answers A, B, and D are incorrect. China uses 784 MHz, Europe uses 868 MHz, and 5 MHz is not used by ZigBee.

  1. Accessing an IPv6 network via an IPv4 network is called what?
    A. CIDR
    B. NAT
    C. Translation
    D. Tunneling

Correct Answer and Explanation: D. Answer D is correct; accessing an IPv6 network via an IPv4 network is called tunneling.

Incorrect Answers and Explanations: A, B, and C. Answers A, B, and C are incorrect. CIDR is Classless Inter-domain Routing, a way to create flexible subnets. NAT is Network Address Translation, which translates one IP address for another. Translation is a distracter answer.