Computer Networking Quiz 4, 5, 6

Packet loss can occur at router output ports and this loss can be prevented by increasing the switch fabric speed.

What is the name of a network-layer packet?

The 8-bit protocol field in the IP datagram contains information about which transport layer protocol (TCP or UDP) the destination host should pass the segment to.

A data plane is responsible for

A control plane is responsible for

Which of these packet queueing disciplines ensure that all packets depart in the order in which they arrived?

Packet loss can be eliminated if the switching fabric speed is at least n times as fast as the input line speed, where n is the number of input ports.

A datagram with a private network address should be able to be present in the larger public Internet.

Type-of-Service field in the IP header can be used to ensure that a packet is forwarded through no more than N routers?

The main function of the control plane is forwarding, which is to determine the paths a packet takes from its source to its destination.

A link-layer switch forwards a packet based on the packet’s MAC (layer 2) address.

The main function of the data plane is packet routing, which is to route datagrams from their input links to their output links.

Suppose there are three routers between a source host and a destination host. Ignoring fragmentation, an IP datagram sent from the source host to the destination host will travel over how many interfaces? How many forwarding tables will be indexed to move the datagram from the source to the destination?

Forwarding is a router’s local action of transferring packets from its input interfaces to its output interfaces, and forwarding takes place at very short timescales (typically a few nanoseconds), and thus is typically implemented in hardware.

Suppose that an arriving packet matches two or more entries in a router’s forwarding table. With traditional destination-based forwarding, what rule does a router apply to determine which of these rules should be applied to determine the output port to which the arriving packet should be switched?

What two types of ICMP messages are received at the sending host executing the Traceroute program?

True or false: Link state algorithms: Computes the least-cost path between source and destination using complete, global knowledge about the network.

What is the purpose of the SNMP trap message?

Suppose you wanted to implement a new routing protocol in the SDN network. At which layer would you implement that protocol?

What are the main network considerations for inter-AS and intra-AS protocols used in the Internet?

Routers use the AS-PATH attribute to detect and prevent looping advertisements; they also use it in choosing among multiple paths to the same prefix.

The NEXT-HOP attribute indicates the IP address of the first router along an advertised path (outside of the AS receiving the advertisement) to a given prefix. When configuring its forwarding table, a router uses the NEXT-HOP attribute.

Logically centralized control means that a logically central routing controller computes and distributes the forwarding tables to be used by each and every router, and each router does not compute its forwarding table, unlike the per-router control.

True or false: When an OSPF route sends its link state information, it is sent only to those nodes directly attached neighbors.

Define the following terms: subnet

In the case of logically centralized control, the data plane and control plane are implemented in separate devices; the control plane is implemented in a central server or multiple servers, and the data plane is implemented in each router.

A distributed routing algorithm calculates the lease-cost path in an iterative, distributed manner by the routers. With a decentralized algorithm, no node has the complete information about the costs of all network links

If we using the analogy of cocktail party interactions, for polling protocol, there isn’t a discussion leader, but there is wine glass that the participants take turns holding. A participant is only allowed to talk if the participant is holding the wine glass.

What are some of the possible services that a link-layer protocol can offer to the network layer?

What is the maximum number of VLANs that can be configured on a switch supporting the 802.1Q protocol?

With IP, datagrams in the same TCP connection can take different routes in the network, and therefore arrive out of order. TCP is still needed to provide the receiving end of the application the byte stream in the correct order.

If we using the analogy of cocktail party interactions, in Token Ring protocol, a discussion leader allows only one participant to talk at a time, with each participant getting a chance to talk in a round-robin fashion.

Suppose nodes A, B, and C each attach to the same broadcast LAN (through their adapters). If A sends thousands of IP datagrams to B with each encapsulating frame addressed to the MAC address of B, what will C’s adapter process do for these frames?

How big is the MAC address space?

Although each link guarantees that an IP datagram sent over the link will be received at the other end of the link without errors, it is not guaranteed that IP datagrams will arrive at the ultimate destination in the proper order.

Suppose nodes A, B, and C each attach to the same broadcast LAN (through their adapters). If A sends thousands of IP datagrams to B with frames with the MAC broadcast address of B, what will C’s adapter process these frames in this case?

How big is the IPv6 address space?