Networking Interview Questions and Answers
Networking Interview Questions and Answers
3-Tier Architecture
In 3-tier Client/Server systems, the application logic resides in the middle tier, separate from the data and user interface. Theoretically, 3-tier systems are more scalable, robust, and flexible.
Example: TP monitor, Web.
2-Tier Architecture
In 2-tier Client/Server systems, the application logic is embedded in the client’s user interface or the server’s database.
Example: File servers and database servers with stored procedures.
Load Balancing
If incoming client requests exceed server processes, a TP Monitor dynamically starts new ones; this is called load balancing.
Fat Clients and Fat Servers
If most application processing occurs on the client-side, it’s a fat client, used for decision support and personal software. If most processing is on the server-side, it’s a fat server, minimizing network interchanges through abstract service levels.
Horizontal and Vertical Scaling
Horizontal scaling adds or removes client workstations with minimal performance impact. Vertical scaling involves migrating to a larger, faster server or multi-servers.
Groupware Server
Groupware manages semi-structured information (text, images, email, bulletin boards, workflow). These Client/Server systems facilitate direct person-to-person contact.
Middleware Classes
- General middleware
- Service-specific middleware
Server Types
- File servers
- Database servers
- Transaction servers
- Groupware servers
- Object servers
- Web servers
File Server
File servers share files across a network. Clients send file requests over the network to the file server.
Client/Server Application Technologies
- Database Servers
- TP Monitors
- Groupware
- Distributed Objects
- Intranets
Client/Server
Clients and servers are separate logical entities collaborating over a network. Many diversely-architected systems connected together are also considered Client/Server.
Benefits of Client/Server TP Monitors
- Client/Server application development framework
- Security firewalls
- High availability
- Load balancing
- MOM integration
- Scalable functions
- Reduced system cost
Operating System Services
Extended services: Add-on modular software components layered on top of base services.
ACID Property
ACID (Atomicity, Consistency, Isolation, Durability) was coined by Andrew Reuter in 1983.
Stored Procedures
A stored procedure is a named collection of SQL statements and procedural logic stored in a server database. It accepts input parameters, allowing a single procedure to be used by multiple clients with different input data. This reduces network traffic and improves performance.
Wide-Mouth Frog
Wide-mouth frog is a simple Key Distribution Center (KDC) authentication protocol.
Passive Topology
Computers passively listen and receive signals without amplifying them.
Example: Linear bus.
Region (Hierarchical Routing)
In hierarchical routing, routers are divided into regions. Each router knows routing details within its region but not the internal structure of other regions.
Virtual Channel
A virtual channel is a connection from one source to one destination (multicast allowed). Also known as a virtual circuit.
Communication vs. Transmission
Transmission is the physical movement of information (bit polarity, synchronization, clock, etc.). Communication is the meaningful exchange of information.
TFTP vs. FTP
TFTP (Trivial File Transfer Protocol) allows file retrieval but lacks reliability and security (uses UDP). FTP (File Transfer Protocol) is a reliable and secure standard for file copying (uses TCP, establishes two connections).
Routing Table Advantages and Disadvantages
Routing tables are fixed, dynamic, or fixed central. Fixed tables require manual updates. Dynamic tables adapt to network traffic. Fixed central tables allow centralized management. Dynamic tables usually cause the fewest administrative problems, although changes may go unnoticed.
Beaconing
A self-repair mechanism where network stations notify others about reception issues. Used in Token Ring and FDDI networks.
Mount Protocol
The Mount protocol returns a file handle and the file system name to the client after receiving a file request.
Digrams and Trigrams
Digrams are the most common two-letter combinations (e.g., th, in, er, re, an). Trigrams are the most common three-letter combinations (e.g., the, ing, and, ion).
HELLO Protocol
The HELLO protocol uses time, not distance, for optimal routing. It’s an alternative to the Routing Information Protocol (RIP).
TCP Segment and IP Datagram Header Length
Minimum: 20 bytes; Maximum: 60 bytes.
Refers to X.3 (PAD function), X.28 (terminal-PAD protocol), and X.29 (PAD-network protocol).
Attenuation
Signal degradation over distance on a network cable.
Protocol Data Unit (PDU)
The LLC-level data unit. It contains a destination service access point (DSAP), a source service access point (SSAP), a control field, and an information field. The control field indicates whether it’s an I-frame, S-frame, or U-frame.
TCP/IP Data Units
Application layer: message; Transport layer: segment or user datagram; Network layer: datagram; Data link layer: frame.
ARP and RARP
ARP (Address Resolution Protocol) maps 32-bit IP addresses to 48-bit physical addresses. RARP (Reverse Address Resolution Protocol) allows a host to discover its IP address knowing only its physical address.
MAC Address
A device’s address at the Media Access Control (MAC) layer. It’s usually stored in the network adapter’s ROM and is unique.
Terminal Emulation
Telnet is a terminal emulation application at the application layer.
Transmission Media
Transmission media are categorized as guided (twisted-pair, coaxial cable, fiber-optic cable) or unguided (wireless, radio, satellite, cellular).
Network Types
- Server-based network: Centralized control of resources.
- Peer-to-peer network: Computers act as both clients and servers.