Questão 1
Questão
Packet loss can occur at router output ports and this loss can be prevented by increasing the switch fabric speed.
Questão 2
Questão
What is the name of a network-layer packet?
Responda
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Frame
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Datagram
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Segment
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All are correct
Questão 3
Questão
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.
Questão 4
Questão
A data plane is responsible for
Responda
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All are correct
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b. the data plane’s input ports perform physical layer function of terminating an incoming physical link at a router,
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c. performs link-layer function to interoperate with the link layer at the other side of the incoming link,
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d. perform lookup function at the input ports
Questão 5
Questão
A control plane is responsible for
Responda
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a. communicating with remote controllers,
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b. responding to attached links that go up or down,
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c. All are correct.
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d. performing management functions.
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e. executing routing protocols,
Questão 6
Questão
Which of these packet queueing disciplines ensure that all packets depart in the order in which they arrived?
Questão 7
Questão
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.
Questão 8
Questão
A datagram with a private network address should be able to be present in the larger public Internet.
Questão 9
Questão
Type-of-Service field in the IP header can be used to ensure that a packet is forwarded through no more than N routers?
Responda
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a. Type-of-Service
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b. Header Length
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c. Upper-layer-protocol
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d. Time-to-live
Questão 10
Questão
The main function of the control plane is forwarding, which is to determine the paths a packet takes from its source to its destination.
Questão 11
Questão
A link-layer switch forwards a packet based on the packet’s MAC (layer 2) address.
Questão 12
Questão
The main function of the data plane is packet routing, which is to route datagrams from their input links to their output links.
Questão 13
Questão
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?
Responda
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a. 8 interfaces; 3 forwarding tables
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b. 3 interfaces; 8 forwarding tables
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c. 5 interfaces; 4 forwarding tables
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d. 4 interfaces; 5 forwarding tables
Questão 14
Questão
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.
Questão 15
Questão
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?
Responda
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a. Find exact prefix matching to forward the packet
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b. To save time, find shortest prefix matching to forward the packet.
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c.Use longest prefix matching to determine which link interface to forward the packet
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d. None of these rules.
Questão 16
Questão
What two types of ICMP messages are received at the sending host executing the Traceroute program?
Responda
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a.ICMP warning message (type 11 code 0) and a destination host unknown ICMP message (type 3 code 7).
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b. ICMP warning message (type 11 code 0) and a destination port unreachable ICMP message (type 3 code 3).
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c. ICMP warning message (type 9 code 0) and a destination port unreachable ICMP message (type 3 code 3).
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d. ICMP Bad IP Header (type 12 code 0) and a destination host unknown ICMP message (type 3 code 7).
Questão 17
Questão
True or false: Link state algorithms: Computes the least-cost path between source and destination using complete, global knowledge about the network.
Questão 18
Questão
What is the purpose of the SNMP trap message?
Responda
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a. A response to a managed device for which the device’s managing server requires notification.
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b.A response to a request on a managed device for which the device’s managing server requires notification.
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c. All are correct.
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d.It is used for notifying a managing server of an exceptional situation (e.g., a link interface going up or down) that has resulted in changes to MIB object values.
Questão 19
Questão
Suppose you wanted to implement a new routing protocol in the SDN network. At which layer would you implement that protocol?
Responda
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a.SDN’s network-control Controller (network operating system) layer
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b. Added to all three layers.
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c. SDN’s network-control application layer
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d. SDN’s network-control data plane layer
Questão 20
Questão
What are the main network considerations for inter-AS and intra-AS protocols used in the Internet?
Responda
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a.
Performance
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b.
Scale
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c.
All are correct.
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d.
Policy
Questão 21
Questão
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.
Questão 22
Questão
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.
Questão 23
Questão
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.
Questão 24
Questão
True or false: When an OSPF route sends its link state information, it is sent only to those nodes directly attached neighbors.
Questão 25
Questão
Define the following terms: subnet
Responda
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a.
All are correct.
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b.
A subnet does not contain a router;
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c.
A subnet is a portion of a larger network;
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d.
Its boundaries are defined by the router and host interfaces.
Questão 26
Questão
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.
Questão 27
Questão
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
Questão 28
Questão
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.
Questão 29
Questão
What are some of the possible services that a link-layer protocol can offer to the network layer?
Questão 30
Questão
What is the maximum number of VLANs that can be configured on a switch supporting the 802.1Q protocol?
Responda
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a. 2048 VLAN
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b. 1024 VLAN
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c. 4096 VLAN
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d. 9192 VLAN
Questão 31
Questão
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.
Questão 32
Questão
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.
Questão 33
Questão
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?
Responda
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C’s adapter will not process the frames, but the adapter will pass the datagrams up the protocol stack
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C’s adapter will not process the frames, and the adapter will not pass the datagrams up the protocol stack
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C’s adapter will process the frames, but the adapter will not pass the datagrams up the protocol stack
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C’s adapter will process the frames, but the adapter will pass the datagrams up the protocol stack
Questão 34
Questão
How big is the MAC address space?
Responda
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a. 2^128 Bits
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b. 2^64 Bits
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c. 2^32 Bits
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d. 2^48 Bits
Questão 35
Questão
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.
Questão 36
Questão
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?
Responda
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C’s adapter will not process the frames, and the adapter will not pass the datagrams up the protocol stack
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C’s adapter will process the frames, but the adapter will not pass the datagrams up the protocol stack
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C’s adapter will both process the frames, and pass the datagrams up the protocol stack
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C’s adapter will not process the frames, but the adapter will pass the datagrams up the protocol stack
Questão 37
Questão
How big is the IPv6 address space?
Responda
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a. 2^48 Bits
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b. 2^64 Bits
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c. 2^32 Bits
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d. 2^128 Bits