Computer Networks

The standard three-tier architecture consists of Presentation layer, Business Logic layer, and Data layer. The terms given (Association layer, Connection layer, Logical layer) are not standard three-tier architecture components, so 'All of the above' is correct as none are fundamental services.

IPX (Internetwork Packet Exchange) is a proprietary protocol developed by Novell, not a universal standard. It was primarily used in NetWare environments but has been largely replaced by TCP/IP. While IPX can work between different LANs, it's not considered a universal standard like TCP/IP, which is the actual universal standard for internetwork communication.

Bridges typically operate using software-based processing on general-purpose CPUs, while switches use hardware-based ASICs (Application-Specific Integrated Circuits) for high-speed frame forwarding. ASICs are specialized chips designed specifically for switching operations, making them much faster than software-based bridging. Options B, C, and D refer to CPU architectures and expansion cards, not switching hardware.

To solve this question, the user needs to have a basic understanding of computer networking and the different components that make up a network. Specifically, the user should be familiar with Ethernet and Frame Relay, as well as the acronyms associated with these technologies.

Explanation of each option:

A. PVC: PVC stands for Permanent Virtual Circuit, which is a type of connection used in Frame Relay networks. This option is correct because PVC is the equivalent of MAC in Ethernet. Both PVC and MAC provide a unique identifier for each device on the network.

B. LCI: LCI stands for Link Connection Identifier, which is a term used in ATM (Asynchronous Transfer Mode) networks. This option is incorrect because it is not related to Frame Relay.

C. DLCI: DLCI stands for Data Link Connection Identifier, which is a term used in Frame Relay networks. This option is correct because DLCI is the equivalent of MAC in Ethernet. Both DLCI and MAC provide a unique identifier for each device on the network.

D. ASIC: ASIC stands for Application-Specific Integrated Circuit, which is a type of integrated circuit designed for a specific application. This option is incorrect because it is not related to either Ethernet or Frame Relay.

Therefore, the correct answer is:

The Answer is: C. DLCI

A CSU/DSU (Channel Service Unit/Digital Service Unit) is the device that connects a router's serial interface to a digital circuit like T1/E1. It performs signal conversion, timing, and line termination functions. An Ethernet card connects to LAN networks, DTE is the router itself (Data Terminal Equipment), and the CSU/DSU is specifically required for WAN digital circuit connections.

An ISDN Terminal Adapter (TA) is the device used to connect non-ISDN equipment (like a router with an RS-232/EIA-232 serial interface) to an ISDN BRI line. It acts similarly to a modem for digital ISDN circuits.

The statement is false because the shared section of a carrier's network is called the 'cloud' or 'backbone', not a WAN. WAN (Wide Area Network) refers to the entire network spanning large geographic areas, including both customer equipment and the carrier's infrastructure. The carrier's shared portion is specifically the network cloud where routing and switching occur.

Source-route bridging is primarily used in Token Ring environments where the source station specifies the entire route through the bridged network in the frame header. This is necessary because Token Ring uses source routing for frame forwarding across multiple rings. Ethernet uses transparent bridging (learning bridges), and switched circuits don't use source-route bridging.

When a switch receives a frame for an unknown destination, it floods the frame to all ports. During this process (and all incoming traffic), the switch examines the source MAC address to build its MAC address table, effectively 'learning' where devices are located.

RJ-11 is the standard 4-pin or 6-pin connector for telephone lines. RJ-45 is for Ethernet networks. COM1 is a serial port identifier, not a connector type. RJ-10 is not a standard connector.

WAN (Wide Area Network) connects computers and networks across large geographic areas, such as cities, countries, or continents, using leased lines or satellite links. Option B is a common misconception but incorrect, while C and D are fabricated terms.

A standard 8-bit SCSI (Small Computer System Interface) bus supports 8 total IDs. One ID is reserved for the controller itself, leaving 7 available IDs for peripheral devices. While newer Wide SCSI supports 15, '7' is the classic answer for a typical adapter.

Internet Authentication Service (IAS) acts as a RADIUS server. A key feature of RADIUS is the use of a 'shared secret'—a text string known only to the RADIUS client (the access server) and the RADIUS server (IAS) to encrypt and authenticate communication.

When a DHCP database is restored, it may not immediately reflect the current state of active leases in the registry. Reconciling the scope compares the DHCP database with the information stored in the registry and fixes inconsistencies, allowing the Active Leases to display correctly.

To answer this question, the user needs to know the network topologies and the protocols that use them. Token Passing is a method of sharing a communication medium between network devices by passing a token among the devices. The device holding the token has the right to transmit data, and after transmission, the token is passed to the next device in the sequence. Token Passing is commonly used in Bus Topology, which is a network topology in which all devices are connected to a central cable.

Now let's go through each option and explain which protocol uses Token Passing in a Bus Topology:

A. 802.1: 802.1 is not a protocol, but rather a family of networking standards that deal with network architecture, management, and security.

B. 802.2: 802.2 is a protocol that defines the Logical Link Control (LLC) sublayer of the Data Link Layer in the OSI model. It does not use Token Passing in a Bus Topology.

C. 802.3: 802.3 is a protocol that defines the Ethernet standard, which is a common protocol used in Local Area Networks (LANs). It does not use Token Passing in a Bus Topology.

D. 802.4: 802.4 is a protocol that defines the Token Bus network, which uses Token Passing in a Bus Topology. However, it is not widely used today.

E. 802.5: 802.5 is a protocol that defines the Token Ring network, which uses Token Passing in a Ring Topology. It is used in some legacy systems but has largely been replaced by Ethernet.

Therefore, the answer is:

The Answer is: D. 802.4