Polycom Interview Questions and Answers

Create and insert nodes in a linked list using C and STL.

• Define a struct for the linked list node

• Allocate memory for the nodes using malloc or new

• Set the data and next pointer for each node

• Use push_back or insert functions in STL for insertion

Deleting a node in a linked list given a pointer to the node.

• Save the next node's pointer in a temp variable

• Copy the data of the next node to the current node

• Delete the next node using the temp variable

TCP/IP protocol stack consists of 4 layers: Application, Transport, Internet, and Network Access.

• Application layer: interacts with user applications and provides services like email, file transfer, etc.

• Transport layer: responsible for end-to-end communication between hosts and provides reliable data transfer using TCP or unreliable using UDP.

• Internet layer: responsible for routing packets across networks using IP addre...read more

A router routes a packet by examining the destination IP address and forwarding it to the appropriate network.

• The router receives a packet from a device on one of its interfaces

• The router examines the destination IP address in the packet header

• The router looks up the destination IP address in its routing table

• The router forwards the packet to the appropriate interface based on the routing table

• If the destination networ...read more

A router uses longest prefix matching to find the most specific route for a packet.

• The router looks at the destination IP address of the packet

• It compares the address with the entries in its routing table

• The router selects the entry with the longest matching prefix

• The packet is then forwarded to the next hop in that route

• If there is no matching prefix, the router uses the default route

• Longest prefix matching ensures ef...read more

Page fault is an error that occurs when a program tries to access a page that is not currently in physical memory.

• Occurs when a program tries to access a page not in physical memory

• Operating system retrieves the page from disk to physical memory

• Can cause performance issues if it happens frequently

• Can be caused by insufficient memory or memory fragmentation

Page fault is serviced by fetching the required page from disk to memory.

• When a process tries to access a page that is not in memory, a page fault occurs.

• The operating system then checks if the page is present in the disk.

• If the page is not present in the disk, it results in a segmentation fault.

• If the page is present in the disk, it is fetched to memory and the process continues.

• The process is then restarted from the

Calculating round trip time and bandwidth of network using Pin

• Use Pin to measure the time it takes for a packet to travel from source to destination and back

• Divide the round trip time by 2 to get the one-way latency

• Calculate bandwidth by dividing the size of the packet by the one-way latency

• Repeat the process with different packet sizes to get an average bandwidth

• Use Pin's built-in tools to analyze the data and generat

Yes, Ping can be used to measure congestion in the system.

• Ping measures the round-trip time for packets to travel from the source to the destination.

• If the round-trip time is high, it indicates congestion in the network.

• Ping can also be used to measure packet loss, which is another indicator of congestion.

Algorithms used in networking include routing, switching, and security protocols.

• Routing algorithms determine the best path for data to travel between devices on a network.

• Switching algorithms determine how data is forwarded between network devices.

• Security algorithms are used to protect data and prevent unauthorized access.

• Examples of routing algorithms include OSPF and BGP.

• Examples of switching algorithms include Spa...read more

Minimum Spanning Tree helps in finding the shortest path in a network.

• MST helps in reducing the cost of network connections.

• It is used in network design and optimization.

• MST algorithms like Kruskal's and Prim's are used in network routing protocols.

• MST can be used to find the shortest path between two nodes in a network.

• Example: MST can be used to find the shortest path for data transmission in a computer network.

Articulation points are nodes in a network whose removal would disconnect the network or increase the number of connected components.

• Articulation points are also known as cut vertices.

• They are significant in network design and analysis as they help identify critical points in the network.

• Removing an articulation point can cause the network to split into multiple disconnected components.

• For example, in a computer networ...read more

Sort an array of 0s, 1s, and 2s without counting their occurrences.

• Use three pointers to keep track of the last index of 0s, 1s, and 2s.

• Iterate through the array and swap elements to their respective pointers.

• Time complexity: O(n), Space complexity: O(1).

A Denial of Service (DoS) attack is an attempt to make a website or network unavailable to users by overwhelming it with traffic.

• DoS attack floods a network or server with traffic to make it unavailable to users

• Remedy includes implementing firewalls, load balancers, and intrusion detection systems

• Another remedy is to use a content delivery network (CDN) to distribute traffic

• Examples of DoS attacks include Ping of Death

DDoS is a cyber attack where multiple systems flood a targeted server with traffic to make it unavailable.

• DDoS attack overwhelms a server with traffic from multiple sources

• Attackers use botnets to launch DDoS attacks

• DDoS attacks can be mitigated by using specialized software and hardware

• Examples of DDoS attacks include the 2016 Dyn cyberattack and the 2018 GitHub attack