Routing Algorithms and Topology Quiz
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Questions and Answers

What is one of the primary requirements of routing algorithms?

  • Complexity in implementation
  • Optimality (correct)
  • Frequent path changes
  • Inefficiency in processing

Routing is only necessary in packet-switched networks.

False (B)

What does the term 'topology' refer to in routing?

Arrangement of nodes and links in a network

The direct connection between two nodes is called a ______.

<p>link</p> Signup and view all the answers

Which of the following terms indicates the value assigned to a link that shows the cost of using it?

<p>Cost (B)</p> Signup and view all the answers

Match the routing terminology with its correct definition:

<p>Link = Direct connection between two nodes Path = A way between two nodes, via one or more links Hop = To traverse a link Cost = Value assigned to link to indicate cost of using that link</p> Signup and view all the answers

What is the purpose of least-cost routing?

<p>To choose a path with least cost</p> Signup and view all the answers

Path changes should be frequent to maintain stability in routing.

<p>False (B)</p> Signup and view all the answers

What is one main disadvantage of simple flooding in network routing?

<p>It leads to sending many copies of packets. (B)</p> Signup and view all the answers

In a flooding protocol, a node can send back a packet to the node that just sent it.

<p>False (B)</p> Signup and view all the answers

What is the purpose of including a hop limit in packet routing?

<p>To discard packets when they exceed a certain number of hops.</p> Signup and view all the answers

Adaptive Routing uses a least-cost routing algorithm to determine a route and adapt the route as network conditions __________.

<p>change</p> Signup and view all the answers

Match the following strategies with their descriptions:

<p>Hop Limit = Counter for packets to prevent indefinite forwarding Selective Flooding = Sending packets to a selection of neighbors Duplicate Detection = Discarding duplicate packets received by the destination Adaptive Routing = Routing that changes based on network conditions</p> Signup and view all the answers

What is a potential result of using the hop limit strategy?

<p>Packets may be discarded if the counter reaches 0. (B)</p> Signup and view all the answers

Selective flooding can be based on probability-based strategies.

<p>True (A)</p> Signup and view all the answers

What is the significance of using a sequence number in packet routing?

<p>To identify and discard duplicate packets received at the destination.</p> Signup and view all the answers

Which algorithm is used in link state routing to determine least-cost routes?

<p>Dijkstra’s algorithm (D)</p> Signup and view all the answers

In link state routing, each node only learns about its direct neighbors.

<p>False (B)</p> Signup and view all the answers

What is the purpose of the link state packet in link state routing?

<p>To send the state of its own links to every other node in the network.</p> Signup and view all the answers

The ________ is used by the flooding protocol to manage link state packets.

<p>sequence number</p> Signup and view all the answers

Match the following steps with their descriptions in link state routing:

<p>Step 1 = Record the state of its own links Step 2 = Send the state of its own links to every other node Step 3 = Form a shortest path tree Step 4 = Build a routing table based on the shortest path tree</p> Signup and view all the answers

What is an advantage of adaptive routing?

<p>It potentially can select the most suited paths. (A)</p> Signup and view all the answers

Adaptive routing is always simple and easy to implement.

<p>False (B)</p> Signup and view all the answers

Name one real routing protocol mentioned in the content.

<p>OSPF</p> Signup and view all the answers

A routing protocol specifies the routing algorithm for determining __________ routes.

<p>least-cost</p> Signup and view all the answers

Match the following routing protocols with their characteristics:

<p>OSPF = Link-state routing protocol RIP = Distance-vector routing protocol BGP = Used for routing between autonomous systems EIGRP = Combines features of link-state and distance-vector protocols</p> Signup and view all the answers

What is a drawback of adaptive routing?

<p>It can create unnecessary overhead in the network. (C)</p> Signup and view all the answers

Reacting too quickly in adaptive routing can cause oscillation.

<p>True (A)</p> Signup and view all the answers

What is the primary function of a routing protocol?

<p>To determine routes in a network automatically.</p> Signup and view all the answers

What is required for circuit establishment in switched networks?

<p>Path established before data transfer begins (A)</p> Signup and view all the answers

Circuit switching allows for data to be transmitted before a circuit is established.

<p>False (B)</p> Signup and view all the answers

What is the main drawback of circuit switching concerning resource allocation?

<p>Resources are reserved for the duration of the connection, which can be inefficient.</p> Signup and view all the answers

In packet switching, data is broken into __________ before being sent.

<p>packets</p> Signup and view all the answers

Match the following types of packet switching with their characteristics:

<p>Datagram Packet Switching = Packets treated independently and can take different paths. Virtual Circuit Packet Switching = Packets follow the same path and arrive in order. Circuit Switching = Path established before data transfer with reserved capacity. Packet Switching = Allows for efficient use of network resources by using packets.</p> Signup and view all the answers

Which type of packet switching ensures that packets arrive in the order they were sent?

<p>Virtual Circuit Packet Switching (C)</p> Signup and view all the answers

In different packet switching methods, packets belonging to the same message always take the same path.

<p>False (B)</p> Signup and view all the answers

What type of applications were originally developed to handle using circuit switching?

<p>Voice traffic</p> Signup and view all the answers

_____________ refers to the approach where each packet is treated independently in packet switching.

<p>Datagram Packet Switching</p> Signup and view all the answers

What is one issue related to the efficiency of circuit-switching?

<p>It can lead to idle resources when not fully utilized. (C)</p> Signup and view all the answers

In packet switching, the same packet can arrive out of order at its destination.

<p>True (A)</p> Signup and view all the answers

What must end devices have for effective circuit switching?

<p>The same speed</p> Signup and view all the answers

In __________ switching, the capacity of the channel must be reserved before communication.

<p>circuit</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Packet Switching = Data is sent in small packets individually. Circuit Switching = A dedicated path is established for communication. Virtual Circuit = Ensures ordered delivery of packets. Datagram = Packets can take different routes and arrive independently.</p> Signup and view all the answers

What is the primary purpose of routing in communication networks?

<p>To determine the path data takes between source and destination (B)</p> Signup and view all the answers

Packet switching is more efficient for delivering telephone calls than circuit switching.

<p>False (B)</p> Signup and view all the answers

Name one algorithm used for determining the shortest path in routing.

<p>Dijkstra</p> Signup and view all the answers

In circuit switching, connections are established for the duration of the ________.

<p>call</p> Signup and view all the answers

Match the following switching methods with their appropriate definitions:

<p>Circuit Switching = Connection remains for the duration of the call Packet Switching = Data is sent in packets over shared networks Adaptive Routing = Adjusts paths based on network conditions Dijkstra = Algorithm for shortest path calculation</p> Signup and view all the answers

Which of the following is a common packet switching technique used in modern WANs?

<p>IP (Internet Protocol) (C)</p> Signup and view all the answers

Adaptive routing strategies are seldom needed in Wide Area Networks (WANs).

<p>False (B)</p> Signup and view all the answers

What describes the role of a switch in a communication network?

<p>Forwarding data between source and destination.</p> Signup and view all the answers

Flashcards

Routing

The process of determining the best path for data to travel from a source to a destination in a network.

Routing Protocols

A set of rules and algorithms used to determine the best routes for data packets in a network.

Network Topology

The arrangement of nodes (computers or devices) and connections (links) in a network.

Link Cost

The value assigned to a connection (link) in a network, representing the cost of using that connection.

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Path (Route)

A sequence of connections (links) that a data packet travels through to reach its destination.

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Link

A direct connection between two nodes in a network.

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Neighbor

A node in a network that is directly connected to another node.

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Least-cost routing

The process of choosing a path with the lowest total cost based on the link costs in the network.

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Flooding

A simple way to distribute network status (topology) information throughout a network. Involves sending a packet to all directly connected neighbors.

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Inefficient

A disadvantage of flooding where sending multiple copies of packets leads to unnecessary network traffic.

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Packet May Not Reach Destination

A disadvantage of flooding where a packet might not reach its destination due to using a hop limit or selective flooding.

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Only Forward Packet Once

A technique used in flooding where each node remembers which packets it has forwarded. prevents redundant transmission.

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Duplicate Detection

A strategy used in flooding to prevent duplicate packets from being delivered to the destination. Each packet is assigned a unique sequence number.

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Hop Limit

A simple mechanism used in flooding to limit the number of hops a packet can travel through a network. Each packet has a hop counter decrement upon forwarding.

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Selective Flooding

A flooding strategy which involves sending packets to a selected subset of neighbors, like randomly chosen ones, rotating destinations, or based on probability.

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Adaptive Routing

Routing strategies that adapt to changing network conditions. They calculate a route using metrics like cost, and adjust as traffic patterns shift.

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Circuit Switching

A method of communication where a dedicated path is established before data transfer begins, ensuring a guaranteed level of quality.

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Packet Switching

A method of communication where data is broken down into small chunks called packets, which are sent independently across the network.

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Circuit-Switched Network

A communication network in which a dedicated path is established between two communicating devices before data transmission begins. This path, known as a circuit, provides a guaranteed bandwidth and quality of service.

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Circuit Establishment

In circuit switching, the process of establishing a connection between two devices, allocating resources on the network for the exclusive use of the connection. This includes resource reservation, bandwidth allocation, and establishing paths through switching nodes.

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Circuit Disconnect

The process of terminating a circuit-switched connection, releasing the resources allocated for the connection, and restoring the network to its original state.

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Data Transfer (Circuit Switching)

The process of transmitting data between two devices over a dedicated path established during circuit establishment. The data can be either analog or digital.

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Packet-Switched Network

A network where data is broken down into packets and sent independently across the network. The path taken by each packet is determined dynamically based on network conditions.

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Datagram packet switching

A technique in packet switching where each packet is treated independently, potentially taking different paths to reach the destination. Packets belonging to the same message may arrive out of order and could be lost in transit.

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Virtual circuit packet switching

A technique in packet switching where a virtual path is established before data transmission begins, ensuring all packets take the same route. This virtual path serves as a logical connection between the source and destination, enabling ordered packet delivery.

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Routing Design

The design of a routing algorithm or strategy, aiming to optimize for factors like speed, efficiency, reliability, and cost.

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Routing Strategies

The different approaches and methods used to determine the best route for data transmission within a network.

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Routing Algorithm

The specific algorithm used by a routing protocol to calculate the least-cost paths.

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Routing Information

Information exchanged between nodes about network topology and costs.

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Routing Metrics

The criteria used to calculate the cost of a path in a routing protocol. Examples include hop count, bandwidth, and delay.

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Local Routing

A routing strategy where each node only considers its immediate neighbors when making routing decisions.

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Global Routing

A routing strategy where each node considers all nodes in the network when making routing decisions.

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Load Balancing Routing

A routing strategy that adapts to changing network conditions by balancing traffic across different paths.

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Link State Packet (LSP) Flooding

Each node in a link-state network sends its own link state information to all other nodes in the network. This information includes details about the node's direct connections, link costs, and the node's own identity.

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Shortest Path Tree in Link-State Routing

A link-state routing protocol uses Dijkstra's algorithm to calculate the shortest paths from the current node to every other node in the network. The result is a shortest path tree.

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Flooding in Link-State Routing

Link state protocols rely on flooding to ensure each node has a complete picture of the network. Every node broadcasts its LSP, which is received and shared by other nodes, ensuring that each node constructs a consistent view of the network.

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Sequence Number in Link State Routing

The link state information carries a sequence number to help detect and discard outdated information. If a node receives the same LSP with a lower sequence number, it knows that the information is stale.

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Hop Count in Link-State Routing

Link state routing uses a hop count to track the number of hops a packet has traveled in the network. This information is used to mitigate the risk of loops and prevent packets from getting stuck in infinite loops.

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Dijkstra's Algorithm

A routing algorithm that finds the shortest path between two points in a network based on the cost assigned to each link. Every node maintains distance information to every destination.

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Bellman-Ford Algorithm

A routing algorithm that repeatedly updates the distances to all nodes to determine the shortest route to a destination. Each node exchanges distance information with its neighbors.

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Study Notes

Circuit Switching Networks

  • Networks use dedicated communication paths between stations
  • The path is a sequence of links between nodes
  • A logical channel is allocated to each physical link for a connection
  • Three phases: establishment, data transfer, and disconnect

Packet Switching Networks

  • For data connections, much of the time the line is idle; circuit-switching is inefficient
  • Packet switching breaks data into packets, sending one at a time from source to destination
  • Two types: Datagram and Virtual Circuit

Datagram Packet Switching

  • Each packet is treated independently of all others
  • Packets belonging to the same message may arrive at destination out of order and may be lost
  • Packets need headers for switches to know where to send them
  • Data is transferred as individual packets taking different paths

Virtual Circuit Packet Switching

  • Virtual circuit setup and teardown
  • Once setup, data is transferred as individual packets taking the same path
  • Packets arrive in-order at the destination, but may be lost
  • Packets need headers for switches to know the next switch

Issues in Circuit Switching

  • Efficiency: Resources are reserved for the duration of the connection, inefficient if applications don't fully utilize the capacity
  • Quality: Data rate and delay are guaranteed for the duration of the connection
  • Link Speeds: End devices must be the same speed

Routing in Switched Networks

  • Routing is a major design issue in switched networks
  • It involves determining the best path for data transfer
  • Real networks have hundreds to thousands of nodes with many possible paths
  • This involves choosing the "best" path

Routing Algorithms

  • Correctness: Paths must go from intended source to intended destination
  • Simplicity: Easy and cheap to implement
  • Robustness: Still deliver despite errors or overload
  • Stability: Path changes should not be too frequent
  • Optimality: Choose best possible paths
  • Fairness: Ensure all stations get equal performance
  • Efficiency: Minimize processing and transmission overhead

Routing Terminology

  • Link: A direct connection between two nodes
  • Path: A sequence of links for data transfer between two nodes
  • Hop: To traverse a link
  • Neighbor: A node at the opposite end of a link
  • Cost: Value assigned to a link to indicate the cost for usage
  • Topology: Arrangement of nodes and links in a network
  • Least-cost routing: Select a path with the lowest cost.

Fixed Routing

  • Uses a single permanent route for each source-destination pair
  • Routes are determined at network startup using a least cost algorithm
  • Cannot respond to traffic changes
  • Simpler but less flexible

Flooding

  • Sends data copies to all neighbors at each node
  • Tries all possible routes; at least one packet will use the shortest route
  • Inefficient for large networks as many copies are sent
  • Includes extensions like hop limit & duplicate detection

Adaptive Routing

  • Uses a least-cost algorithm that adapts to changing network conditions dynamically
  • Requires network status information from: local node, adjacent nodes, or all nodes
  • More complex but can improve performance on networks with dynamic conditions

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Description

Test your understanding of routing algorithms and network topology with this quiz. Explore key concepts such as least-cost routing, network stability, and selective flooding. Perfect for students in computer networking courses.

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