4A0-100 Sample Questions Answers

You cannot have overlapping IP addresses. Customers must change their IP address assignment.

Each VPRN service maintains a separate VPN routing and forwarding instance to separate customer routing information. This allows for overlapping addresses.

A VPRN ignores IP addressing information and uses MAC addressing instead, which are always unique.

A VPRN translates customer IP addresses to a private addressing scheme administered by the service provider.

UDP has less overhead because it is only used for transmission of small amounts of data.

UDP has less overhead then TCP because there is no checksum field in UDP.

UDP overhead is the same as TCP because it uses the same fields in the header.

UDP has less overhead because there is no requirement for acknowledgment or retransmission.

R3 discards the LSA received from R1 and sends a copy of the LSA from its link state base to R1.

R3 installs the LSA received from R1 in its link state database and floods a copy to its neighbors.

R3 discards the LSA received from R1 and sends an ACK to R1.

R3 installs the LSA received from R1 in its link state database, sends an ACK to R1 and floods a copy to its neighbors.

Responds in real time to network failures.

Can only be used for routing within an autonomous system.

Uses a hop-count metric to determine the best route to a network.

Explicitly defines the next-hop based on operator input.

The host will retransmit the frame if it detects a collision during transmission.

The host is able to detect the transmission speed of the Ethernet switch port to which the host is connected.

The host will only transmit data when it detects that no other devices are transmitting.

The host will only transmit upon a timer expiry.

The host will only transmit when it receives the token.

The CE device removes the MPLS label.

The last LSR on the LSP removes the MPLS label.

MPLS labels are not removed until they reach the final destination.

The egress LER removes the MPLS label.

The allocation of enterprise IP address space

The allocation of residential IP address space

The allocation of global IP address space

The allocation of North American IP address space

LDP monitors the available bandwidth on all links and signals the LSP based on this information.

LDP uses the shortest hop-count between two endpoints for the LSP.

LDP must be configured hop-by-hop by the service provider.

LDP follows the path chosen by the IGP.

Provides a data transport service to higher protocol layers.

Provides a data transport service for routing and control protocols such as OSPF and ICMP.

Provides a universal address plan to uniquely identify every device in the network.

Defines a standard method for framing data for transmission on the physical network medium.

It forwards the packet to the next LSR without altering the MPLS label.

It swaps the MPLS label and forwards the packet to the next LSR.

It pushes a new MPLS label and forwards the packet to the next LSR.

It pops the MPLS label and forwards the packet to the next IP router.

A demarcation point

An Internet exchange point

A regional Internet registry

A point of presence

SF 1

SF 2

SF 3

Both CF1 and CF2

Ctrl-z

Ctrl-c

Esc

Shift-Page Down

10.2.3.2

10.2.3.1

192.168.2.0

10.1.1.1

Both ARP request and response messages are unicast messages.

Both ARP request and response messages are broadcast messages.

An ARP request is a broadcast message, while an ARP response is a unicast message.

An ARP request is a unicast message, while an ARP response is a broadcast message.

Real-time audio application such as VoIP.

Web browser.

Email application.

Telnet.

Host A has received a request to establish a TCP session.

Host A has received a request to close a TCP session

A TCP session is now established to host A.

The TCP session has been terminated due to a timeout.

A VPLS operates as if 2 sites are directly connected by a single cable.

A VPLS operates as if multiple sites are connected through a single switched LAN.

A VPLS operates as if multiple sites are connected through a single router.

A VPLS operates as if multiple sites are connected through a series of private point-to-point routed connections.

To the customer, it appears as if all sites are directly connected by a single cable.

To the customer, it appears as if all sites are connected through a single switched LAN.

To the customer, it appears as if all sites are connected through a single router.

To the customer, it appears as if all sites are connected through a series of private point-to-point connections.

File sizes

Port statistics

Log-id 100 files

TiMOS image files

config router static-route 0.0.0.0/0 next-hop 10.2.3.2

config router static-route 0.0.0.0 next-hop 10.2.3.2

config router static-route 10.2.3.2 next-hop 0.0.0.0/0

config router default-route 10.2.3.2

config router static-route 0.0.0.0 next-hop 192.168.2.0

A router ID is not required by OSPF.

The system address is used as the router ID if router-id is not set.

The router ID is used to uniquely identify every OSPF router.

On the Nokia 7750 SR, the router ID is set to the highest logical IP address if router-id is not explicitly set.

Virtual Private Wire Service .

Virtual Private LAN Service.

Virtual Private Routed Networks.

Virtual Private Dark Fiber Service.

IEEE

IETF

NSFNET

ITU-T

APNIC

Network Solutions INC

IANA

IETF

ITU-T

IEEE

The Service ATM Point is used for ATM connections to a PE.

The Service Access Point is defined on the PE device and is the customers access to the service.

The Service Access Point is defined on the P device and is the customers access to the service.

The Service Access Point is defined on the CE device and is the customers access to the service.

Customer traffic is encapsulated with a service label by the ingress PE. The service label identifies which transport tunnel to use.

Customer traffic is encapsulated with a service label by the egress PE. The service label identifies which transport tunnel to use.

Customer traffic is encapsulated with a service label by the egress PE. The service label identifies the specific service the data belongs to.

Customer traffic is encapsulated with a service label by the ingress PE. The service label identifies the specific service the data belongs to.

An entry included in the default configuration of the router that is used if no dynamic routing protocols or static routes are configured.

A wildcard entry used when the destination network is not specifically defined in the routing table.

An entry selected based on the route that has the least cost to the destination (path with the most physical bandwidth)

An entry used by the routing protocol when it is unable to calculate the best route to the destination.

A string of consecutive 1's.

A string of consecutive 0's.

A string of alternating 10's.

The network address is determined by masking the source address with a port's if Index binary representation.

Source port.

MTU.

Sequence number.

Acknowledgement number.

Window size.

IGP

IBGP

EBGP

EGP

BGP cannot be run between routers in different ASs.

Based on the metrics of the routing protocol, find the best path to the destination network and install it in the routing table.

Provide a CLI interface to allow the operator to configure the dynamic routing protocol on the router.

Based on the routing protocol preference values, chose the route with the lowest preference and install it in the routing table.

Provide a CLI interface to allow the network operator to install static routes in the routing table.

Using the IP address of the packet.

Using the MAC address of the frame.

Using port numbers.

Using Connection Identifier Numbers (CIN).

R3 discards the LSA received from R1 and sends a copy of the LSA from its link state base to R1.

R3 installs the LSA received from R1 in its link state database and floods a copy to its neighbors.

R3 discards the LSA received from R1 and sends an ACK to R1.

R3 installs the LSA received from R1 in its link state database, sends an ACK to R1 and floods a copy to its neighbors.

Interface MTU.

Area ID.

Authentication password.

Hello interval.

Dead interval.

Router priority.

At the edge of the provider's network facing the customer.

At the edge of the customer's network facing the provider.

In the core of the provider's network.

On the customer premises.

From the customers perspective it looks as if all sites are connected by the same set of dark fibers.

From the customers perspective it looks as if all sites are connected to a private switched network administered by the service provider.

From the customers perspective it looks as if all sites are connected to a private routed network administered by the service provider.

From the customers perspective it looks as if all sites have public internet access administered by the service provider.

Ethernet.

ATM.

Frame Relay.

Token Ring.

The combination of IP source and destination address and TCP source and destination port uniquely identifies each session.

The combination of IP source and destination address and the IP protocol field uniquely identifies each session.

The hosts can identify the sessions using each others MAC addresses.

Two hosts can not have multiple TCP sessions simultaneously.

65001

65003

2002

All of the above.

None of the above.

It restricts the sender from sending too much data when there is congestion in the network.

It allows the receiver to control the rate at which the sender transmits data.

It forces the sender to send only one segment at a time.

It allows the receiver to drop segments without the sender having to retransmit.

config router static-route 192.168.2.0/24 next-hop 10.2.3.2

config router static-route 10.2.3.1 next-hop 192.168.2.0

config router static-route 192.168.2.0/24 next-hop 10.2.3.1

config router static-route 10.2.3.2 next-hop 192.168.2.0

OSPF

BGP

X.500

IS-IS

Ethernet

It is a broadcast technology that can send frames to all devices attached to shared media.

It uses a passive, wait-listen protocol called Carrier Sense Multiple Access with Collision Detection (CSMA/ CD).

It uses IP addresses to identify interfaces on the common network media.

It is part of the network interface layer of the TCP/IP protocol suite.

Devices on different VLANs cannot communicate with each other.

Devices on different VLANs can communicate with each other as long as they are connected to the same switch.

Devices on different VLANs can communicate with each other as long as the switches they are attached to are connected to each other with an Ethernet connection.

Devices on different VLANs can communicate with each other if there is an IP router to connect the VLANs.

Application data is transported in 53-byte cells.

ATM circuits are identified by a VPI/VCI value.

Provides enhanced QoS support with 5 classes of service.

Ideal for multiple services on the same physical line.

All of the above.

None of the above

Application Layer.

Transport Layer.

IP Layer.

Data Link Layer

An application and session layer.

A network layer that provides a universal and consistent forwarding service.

A transport layer with two protocols.

An applications services layer with similar layering and service definitions.

Resolves a Mac address given a specific IP address.

Allows a single public IP address to represent multiple private IP addresses simultaneously.

Maps a private address to a well known port number.

Provides a one to one mapping from a private to a public address.

172.16.224.255/18

255.255.255.255/32

224.1.2.1/8

192.168.24.59/30

It records the destination MAC address and the interface on which it arrived.

It records the source MAC address and the interface on which it arrived.

It floods the frame out of all its interfaces except the interface on which the frame arrived.

It transmits the frame out of the appropriate interface.

Providing path redundancy.

Preventing loops.

Handling collisions.

Allowing flooding of multicast traffic.

IBM.

US Military.

Nokia.

NASA.

Bell Labs

AAL0

AAL1

AAL2

AAL3/4

AAL5

It forwards the data to the switch fabric.

It discards excess data packets.

It converts the incoming data to an internal format.

It performs Quality of Service operations and buffers incoming data.

PPP supports multipoint access networks with many stations. The all 1's acts as a broadcast.

PPP supports multipoint access networks with many stations. The all 1's acts as a multicast.

PPP supports point-to-point networks only. The address field is fixed.

PPP supports point-to-point networks only. The address field can change dynamically since every station is assigned a PPP address.

17.23.119.63

87.99.12.159

95.11.22.93

192.11.25.87

VLAN tag.

IP Header.

FCS.

Priority Value.

STM-1 with a bit rate of 1.544 Mbit/s

STM-1 with a bit rate of 2.048 Mbit/s

STM-1 with a bit rate of 51.84 Mbit/s

STM-1 with a bit rate of 155.52 Mbit/s

There must be multiple ports assigned to the LAG.

All ports in the LAG must be configured with the same characteristics.

Auto-negotiation must be enabled on all ports in the LAG.

All of the above.

The Data Link Layer is responsible for encapsulating the packet into a frame for transmission on the transmission media.

The Data Link Layer is responsible for encapsulating the packet into an IP header and routing the packet.

The Data Link Layer is responsible for formatting the packet for applications such as JPEG format.

The Data Link Layer is responsible for timing of the signals on the transmission media

If dynamic-cost is enabled it will adjust the cost for routing protocols such as OSPF.

If dynamic-cost is not enabled it will adjust the cost for routing protocols such as OSPF by dividing the link bandwidth by 2.

The LAG will be changed to an operational state of 'down'.

The LAG will function with only 2 ports. There will be no change to the routing metric.

Ethernet.

Token-Ring.

SONET/SDH.

E1 carrier.

PPP

The internet emerged in the commercial world in the 1980’s following the US military’s adoption of TCP/IP in 1983.

The internet evolved from a military to a research to a commercial based network.

The internet remained primarily a research based network and was only commercially adopted in 2000 when the world wide web was conceived.

Internet service providers provided the services necessary for military based networks to evolve into research and education based networks.

1

2

3

4

The provider edge (PE) switch adds an additional field called a PE tag to the customers Layer 2 data.

The PE switch replaces the customers VLAN tag with a carrier-assigned tag.

The PE switch adds a second VLAN tag to identify the customers traffic on the carriers network.

The PE switch assigns a customer-specific priority label to the customers traffic.

DCHP

ICMP

ARP

NAT

Support for IPv6.

Support for POS.

Upgrade path to the Nokia 7750 SR.

Support for IS-IS

The MDA contains the flexible fast path complex used for forwarding data.

Excess data is discarded by the MDA and the remaining data forwarded for QoS processing.

The MDA buffers data and applies Quality of Service (QoS) to classify and treat the data appropriately.

The MDA converts data from its incoming physical format into an internal format and provides some minimal buffering.

Unicast address.

Broadcast address.

Multicast address.

Anycast address.

Destination address

Frame check sequence

Preamble

Length field

time-display

help

type

terminal

Routers send a copy of their routing table to their neighbors periodically.

Routers flood link information throughout the entire area.

Network converges quickly (within several seconds) after a topology change.

Routers do not have precise knowledge of the entire network topology.

32-bit network prefix.

24-bit network prefix.

16-bit network.

8-bit network.

ARPANET was an early packet switched network initially connecting 4 sites (Stanford, UC Santa Barbara, UCLA, and U of Utah).

The mission of ARPANET was to connect packet switched networks and other diverse networks, making an international network of networks.

ARPANET connected sites spread around the Hawaiian Islands to a central time-sharing computer on the University of Hawaii campus.

ARPANET was based on the use of TCP/IP to interconnect diverse systems.

the application services layer

The transport layer

The Internet protocol layer

The network interface layer

On the CE device.

On the PE device.

On the P device.

On both CE and PE devices.

1/1/1

1/1/2

1/1/3

1/1/4

Each customer’s traffic is isolated from other customers.

Service providers utilize a shared infrastructure to support multiple VPNs.

Customer data is altered as it traverses a VPN.

A VPN is created specifically to meet the requirements of each customer.

Two sites are directly connected by a single cable.

Two sites are connected through a single switched LAN.

Two sites are connected through a public routed network.

Two sites are connected through a private routed network.

IP filters can be applied on inbound traffic, outbound traffic, or both.

IP filters can be created to filter based on IP and MAC addressing.

By default, no IP filter is applied to an interface.

The default action of an IP filter is to forward packets.

Checksum

SYN

Destination port

Window size

MTU

The receiving end station sends an ACK flag with SEQ=28000 to indicate it has received a segment out of order.

The receiving station sends a NACK frame with SEQ=28500 requesting that the frame be retransmitted

Once the reciever's window is full. TCP assembles the payload and determines that SEQ=28500 is missing. At this point, the reciever sends the RST flag with SEQ=28500 to Request Single Transmission of the missing segment.

TCP will collect the segments and forward them to the application layer where the SEQ numbers will be processed and a retransmit request will occur for the entire packet.

CPM management Ethernet port

CPM console serial port

Port 1/1/1

Any port on an installed MDA

136.160.17.128/25

136.160.17.192/26

136.160.17.192/27

136.160.17.192/28

The Media Dependent Adapter (MDA)

The Input/ Output Module (IOM)

The eXpandable Media Adapter (XMA)

The Control Processor Module (CPM)

A sequence of label actions from one LER to another LER represents a logical tunnel known as an LSP.

MPLS labels must be dynamically signaled.

Labels are globally significant to the MPLS network.

MPLS labels may be dynamically signaled or statically assigned by the service provider.

Labels are locally significant to the MPLS router.

A passive device used to connect cables without signal amplification.

A device that receives and retransmits data without Layer 2 header inspection.

A device that receives and retransmits data based on the Layer 2 destination address.

A device that receives and retransmits data based on the Layer 3 destination address.

System interface

Interface “toC1”

Interface “toP1”

Interface “toP2”

The subnet has only one address reserved for a loopback interface or the system interface.

The subnet has a broadcast address.

The subnet is configured for a point-to point link.

The subnet is reserved for a multicast address groups.

?

Tab

Space bar

Return

eBGP peering sessions with routers R1, R3 and R4

iBGP peering sessions with routers R1 and R5

An eBGP peering session with router R1, and iBGP peering sessions with routers R3 and R4

An iBGP peering session with router R1, and an eBGP peering session with router R4

Console

CLI

Memory

File

To provide an address that refers to all devices in a network.

To provide an address that refers to a specific group of devices in a network.

To provide an address that refers to a group of devices with the same IP address in different Layer 2 networks.

To provide an address that refers to a single device in a network.

It is responsible for encapsulating packets into frames for transmission on physical media

It is responsible for encapsulating packets into IP datagrams and routing them

It is responsible for encapsulating application data into TCP/UDP messages

It is responsible for the timing of the signals on physical media.

An IP filter is used to discard packets with checksum errors.

An IP filter can allow IP packets into a network or deny IP packets from entering a network.

Multiple ingress and egress filter policies can be applied to a network interface.

Once an IP filter is applied, it cannot be modified.

To select from routes with different next-hops.

To select from routes with different costs.

To select from routes learned from different routing protocols.

To select from routes with different prefixes.

10.10.10.0

10.10.10.1

10.10.10.2

10.10.10.3

Route learned from router R1.

Route learned from router R2.

Router learned from router R3.

Route learned from router R4.

Layer 3 direct internet access service

Layer 3 IP routed service

Layer 2 point-to-point service

Layer 2 multipoint service

An MPLS network with multiple LSPs to the same LER.

An OSPF network with equal cost multiple paths.

A SONET network with a ring topology.

An Ethernet network with redundant paths not running STP.

1

2

5

6