Computer Networksकंप्यूटर नेटवर्क questions and answersप्रश्न और उत्तर

How computer networks worksकंप्यूटर नेटवर्क को समझिए

Each layer serves the one above it: the transport layer (TCP/UDP) gives end-to-end delivery, the network layer (IP) routes packets, the data-link layer moves frames on one link.

TCP is connection-oriented and reliable; UDP is connectionless and faster, suited to streaming and DNS lookups.

A subnet mask splits an IP address into network and host bits; usable hosts are 2^(host bits) minus the network and broadcast addresses.

Each trick says when to use it, why it works and when it fails. Formula tricks are checked by code over their whole range.हर ट्रिक बताती है कि उसे कब इस्तेमाल करें, वह क्यों काम करती है और कब नहीं। सूत्र वाली ट्रिक्स को कोड से उनकी पूरी रेंज पर जाँचा गया है।

Answers and full solutions are shown. Hide them to test yourself first.उत्तर और पूरे हल दिखाए गए हैं। पहले खुद को परखने के लिए इन्हें छिपाइए।

1. Example 1उदाहरण 1 · Computer Networks · Easyआसान

   A socket is uniquely identified by which combination?

   1. IP address and port number
   2. MAC address and port number
   3. IP address only
   4. Port number only
   Answer:उत्तर: IP address and port number

   1. Recall socket = (IP, port) pair for each endpoint.
   2. Both source and destination sockets use this tuple.

2. Example 2उदाहरण 2 · Computer Networks · Mediumमध्यम

   Host X wants to send a frame to Host Y on the same Ethernet LAN. Host X knows Y's IP address but not its MAC address. Which protocol does Host X use to discover Y's MAC address?

   1. RARP
   2. ARP
   3. ICMP
   4. DHCP
   Answer:उत्तर: ARP

   1. Host X needs MAC for known IP.
   2. It broadcasts ARP request.
   3. Host Y replies with its MAC.

3. Example 3उदाहरण 3 · Computer Networks · Hardकठिन

   A network administrator allocates the IPv4 block 192.168.10.0/24 for a new office. She needs to create 4 equal-sized subnets. What is the subnet mask for each subnet in dotted decimal notation?

   1. 255.255.255.192
   2. 255.255.255.224
   3. 255.255.255.240
   4. 255.255.255.248
   Answer:उत्तर: 255.255.255.192

   1. Original prefix /24.
   2. Need 4 subnets => borrow 2 bits (2^2=4).
   3. New prefix = 26.
   4. Convert /26 to dotted decimal: 255.255.255.192.

4. Example 4उदाहरण 4 · Computer Networks · Mediumमध्यम

   Host X wants to send a frame to Host Y on the same Ethernet LAN. Host X knows Y's IP address but not its MAC address. Which protocol does Host X use to discover Y's MAC address?

   1. RARP
   2. ARP
   3. ICMP
   4. DHCP
   Answer:उत्तर: ARP

   1. Host X needs MAC for known IP.
   2. It broadcasts ARP request.
   3. Host Y replies with its MAC.

5. Example 5उदाहरण 5 · Computer Networks · Mediumमध्यम

   Host X wants to send a frame to Host Y on the same Ethernet LAN. Host X knows Y's IP address but not its MAC address. Which protocol does Host X use to discover Y's MAC address?

   1. RARP
   2. ARP
   3. ICMP
   4. DHCP
   Answer:उत्तर: ARP

   1. Host X needs MAC for known IP.
   2. It broadcasts ARP request.
   3. Host Y replies with its MAC.

6. Example 6उदाहरण 6 · Computer Networks · Mediumमध्यम

   In a routing table, what does the metric value represent?

   1. The IP address of the next hop
   2. The administrative distance of the route
   3. The cost to reach the destination network
   4. The subnet mask of the destination
   Answer:उत्तर: The cost to reach the destination network

   1. Identify the columns in a typical routing table.
   2. Metric indicates path cost (e.g., hop count, bandwidth).

Common mistakesआम गलतियाँ

• Putting routers at the data-link layer.
• Forgetting to subtract 2 when counting usable hosts.
• Calling UDP reliable.

Frequently asked questionsअक्सर पूछे जाने वाले प्रश्न