MIS 4123 Test 2 Study Guide

Which of the following is classified as an APIPA address?

169.254.10.125. When a workstation cannot obtain an IP address from a DHCP server, oftentimes an IP address will be autogenerated by automatic private IP addressing (APIPA). The IP addresses are in the range 169.254.0.1 to 169.254.255.254. The correct response is B. The other responses are valid IP addresses that are either statically assigned or dynamically assigned by a DHCP server.

If an Ethernet port on a router was assigned an IP address of 172.16.112.1/25, what would be the subnet address of this host?

172.16.112.0. A /25 mask is 255.255.255.128

Distinguish between asynchronous and synchronous transmission

Asynchronous transmission is often referred to as start-stop transmission because the transmitting computer can transmit a character whenever it is convenient, and the receiving computer will accept that character. With asynchronous transmission, each character is transmitted independently of all other characters. Which synchronous transmission, all the letters or data in one group of data are transmitted at one time as a block of data

What are the three fundamental approaches to routing?

Centralized, static routing, and dynamic routing.

You need to make sure that the time is consistent across all your network devices. What protocol do you need to run on your network?

Network Time Protocol (NTP) will ensure a consistent time across network devices on a network

Which of the following is true when describing a unicast address?

Packets addressed to a unicast address are delivered to a single interface. For load balancing, multiple interfaces can use the same address

Which of the following is true when describing a multicast address?

Packets are delivered to all interfaces identified by the address. This is also called a one-to-many address. Packets addressed to a multicast address are delivered to all interfaces identified by the multicast address, the same as in IPv4. A multicast address is also called a one-to-many address. You can tell multicast addresses in IPv6 because they always start with FF.

What is the purpose of the source port identifier?

The source port identifier of the received TCP segment tells the destination station which application layer process the packet is from.

Which media is least susceptible to noise?

Fiber optic cable

Which of the following is classified as Class B private IP address?

172.16.169.254. RFC 1918 specifies IP addresses for private networks. These are IP addresses that reserved for hosts that do not need direct access to the Internet or other enterprise WANs. There are three banks of private IP addresses, one for each address class: i. 10.0.0.0 to 10.255.255.255 ii. 172.16.0.0 to 172.31.255.255 iii. 192.168.0.0 to 192.168.255.255

If given a router's IP address with CIDR, be able to identify valid hosts. Your router has the following IP address on Ethernet0: 172.16.2.1/23. Which of the following can be valid host IDs on the LAN interface attached to the router?

172.16.2.255, 172.16.3.0. The router's IP address on the E0 interface is 172.16.2.1/23, which is a 255.255.254.0. This makes the third octet a block size of 2. The router's interface is in the 2.0 subnet, and the broadcast address is 3.255 because the next subnet is 4.0. The valid host range is 2.1 through 3.254. The router is using the first valid host address in the range.

c. Given the host IP, 10.1.3.65/23, what subnet is this host in?

2

a. Which of the following is the default subnet mask for a Class B IPv4 address?

255.255.0.0. A subnet mask is a 32-bit number used with an IP address to distinguish the network portion of an IP address from the host portion. It is also useful for determining whether a destination is on a local segment/subnet or a remote segment/subnet. Each IP address class has a default subnet mask

Which of the following ports are matched with the correct protocol?

: UDP port 15 for NETSTAT, TCP port 21 for FTP, TCP port 23 for Telnet, TCP port 25 for SMTP, UDP and TCP port 53 for DNS, TCP port 110 for POP3, and TCP port 119 for NNTP

What are the key deliverables for the cost assessment step?

? (1) RFP; (2) revised physical network diagram; (3) business case, defined in business objectives and business language, that supports the network design.

You have an interface on a router with the IP address of 192.168.192.10/29. Including the router interface, how many hosts can have IP addresses on the LAN attached to the router interface?

A /29 (255.255.255.248), regardless of the class of address, has only 3 host bits. Six hosts is the maximum number of hosts on this LAN, including the router interface

What is the highest usable address on the 172.16.1.0/24 network? 172.16.1.254

A 24-bit mask, or prefix length, indicates that the entire fourth octet is used for host identification. In a special case, such as this, it is simpler to visualize the all-zeros value (172.16.1.0) and the all-ones value (172.16.1.255). The highest usable address, the last one before the all-ones value, is 172.16.1.254.

The purpose of a bridge is to ____________ filter data on a network by MAC address.

A bridge connects different segments of a network in order to expand the scope of the network. Bridges filter data on a network by MAC address to isolate traffic on a network segment. Bridges are used as a tool on overloaded networks. By filtering data based on MAC address, they efficiently transmit data between sending and receiving devices. Traffic between segments is reduced and network throughput is increased with a bridge. Routers connect network subnets. CSU/DSUs prepare signals for WAN transmission. Repeaters are network devices that amplify data signals and all accompanying noise.

What is a bottleneck?

A circuit that is filled almost to its capacity and thus is the critical point that determines whether users get good or bad response times is referred to as a bottleneck.

Which network device protects a local network's resources from external attacks?

A firewall is a combination of hardware and software technologies usually implemented in a multihomed computer or a dedicated device such as a Cisco PIX box, with one port connected to the private network and one to the public network. Its purpose is to protect a local network's resources from external attacks. Gateways, modems, and WAPs are network connectivity devices whose primary purpose is not to protect a network from external attacks but to connect network devices and segments

What is a subnet?

A subnet refers to a group of computers that are logically grouped together by IP number.

What is the turnpike effect?

A turnpike effect results when a network is used to a greater extent than was originally anticipated by the network designer.

What is the purpose of an ARP broadcast? What type of request must a client send if it does not know the destination MAC address?

ARP broadcast. This is step 6 in the IP routing process. If the hardware address isn't in the ARP cache of the host, an ARP broadcast is sent out onto the local network to search for the hardware address

What does ARQ mean? Distinguish between the two types of ARQ.

ARQ means that a receiver that detects an error in a message simply asks the sender to retransmit the message until it is received without error. Stop-and-Wait ARQ - the sender stops and waits for a response from the receiver after each data packet. Continuous ARG is a full-duplex transmission technique, because both the sender and the receiver are transmitting simultaneously.

What is an effective way to prevent attenuation?

Adding repeaters or amplifiers to a circuit

What is the advantage of using DHCP in a network environment?

An advantage of using DHCP in a network environment is that it assigns IP addresses to host. Remember that DHCP servers assign IP addresses to hosts. Thus, DHCP allows easier administration than providing IP information to each host by hand (called static IP addressing)

Why do errors occur on a network?

Because of noise on the line

What is circuit loading?

Circuit loading refers to the amount of data transmitted on a circuit.

Distinguish between connection-oriented messaging and connectionless messaging? When are they used?

Connection-oriented messaging sets up a TCP connection (also called a session) between the sender and receiver. Connectionless communication is most commonly used when the application data or message can fit into one single packet. Connectionless.

e. You have established a wireless network in your SOHO. Your office is in one building, and your laptop, where you monitor your email, is in your home office, which is 75 yards across your yard. There is a clear line of sight between your home and your office. The wireless router is an 802.11g unit, with four LAN ports. It functions as a firewall, NAT server, and DHCP server. Computers in the office never have issues with connectivity. Office computers can access local resources and Internet resources. Your laptop has been having problems accessing office resources and Internet resources. When you take the laptop to the office and connect it with a patch cable, everything works fine. What is the most likely problem?

DHCP configuration information is not being transmitted across the wireless network. The typical reason why a node cannot access network resources is that it is not getting IP address configuration from a DHCP server. If the server is up and other nodes are getting their configuration, then the problem is that the wireless component is experiencing some problem with DHCP IP address distribution by means of a broadcast. This is confirmed when you hardwire the laptop to the router and you are able to access resources. If DNS, WINS, or NAT were problematic, then you still would be able to see some network resources but your access would be limited.

What information does a router require to make a routing decision?

Destination network (address) and Neighbor router. A frame uses MAC addresses to send a packet on the LAN. The frame will take the packet to either a host on the LAN or a router's interface if the packet is destined for a remote network.

Know how a routing protocol determines the best route.

Distance vector routing protocols use a single value such as hop count as its metric, which in turn is used to compare routes. Hybrid routing protocols use a combination of distance vector and link state features to determine route cost. Link state protocols calculate a sophisticated value know as cost to compare routes. Finally there is no Distance link type of routing protocol

You want to implement a mechanism that automates the IP configuration, including IP address, subnet mask, default gateway, and DNS information. Which protocol will you use to accomplish this?

Dynamic Host Configuration Protocol (DHCP) is used to provide IP information to hosts on your network. DHCP can provide a lot of information, but the most common is IP address, subnet mask, default gateway, and DNS information.

Which protocols support VLSM, summarization, and discontiguous networking? (choose 3)

EIGRP, OSPF, RIPv2

Define the term, capacity planning.

Estimating the size and type of the "standard" and "advanced" network circuits is called capacity planning

What byte size address is IPv4 based on? What byte size address is IPv6 based on?

IPv6 is based upon 16-byte addresses. IPv4 is based on 4-byte addresses.

Users arrive at the office after a weekend and the hosts that were shut down over the weekend are restarted but cannot access the LAN or Internet. Hosts that were not shut down are working fine. Where can the problem be?

If the DHCP server has stopped functioning, it will not hand out IP addresses to hosts that are restarted. However, the hosts that were not shut down still have an IP addresses because the lease time has not expired.

You receive a call from a user who is complaining that they cannot get on the Internet. You have them verify their IP address, mask, and default gateway. The IP address is 10.0.37.144, with a subnet mask of 255.255.254.0. The default gateway is 10.0.38.1. What is the problem?

Incorrect gateway IP. The host ID of 10.0.37.144 with a 255.255.254.0 mask is in the 10.0.36.0 subnet (yes, you need to be able to subnet in this exam!). Do not stress that this is a class A, what we care about is that the third octet has a block size of 2, so the next subnet is 10.0.38.0, which makes the broadcast address 10.0.37.255. The default gateway address of 10.0.38.1 is not in the same subnet as the host. Even though this is a Class A address, you still should easily be able to subnet this because you look more at the subnet mask and find your interesting octet, which is the third octet in this question. 256 - 254 = 2. Your block size is 2

7. Describe NAT. Distinguish between NAT terms (identified in Table 8.4). Which of the following describes an IP address as it exists on the LAN before translation by NAT?

Inside local. An IP address as it exists on the LAN before translation by NAT is called an Inside local address. After the NAT device translates the address to a public address it is called inside global. An Outside global address is the name of a destination host before translation and Outside local is the name of the same address after translation.

What are reasons for subnetting a network?

Isolates the network from others, improves performance. Subnetting is the process of dividing a 32-bit address space to allow for more hosts and/or networks. Subnetting is accomplished by assigning a subnet mask to an IP address. The mask defines the network portion, the subnet portion, and the host portion of an IP address. The benefits of subnetting include the following: i. Decreases congestion and improves performance while minimizing traffic ii. Enhances security by isolating the network from outside influences iii. Optimizes the use of a given IP address space

How is the value of the administrative distance of a route used?

It rates the trustworthiness of the route. Administrative distance is a description of the trustworthiness of the route. When a route has been learned in more than one way, perhaps from different routing protocols, this value is used to choose among the information sources. It does not describe the ease of administration of the route, nor the percentage of time the route has been available. Lastly it is NOT used to determine the best route. The cost values are used for that determination

What are the advantages of using dynamic routing protocols?

It simplifies administration. It allows for automatic reaction to lost routes. It allows for the determination of the best route. A negative of dynamic routing protocols is that it will actually increase network traffic due to the routing update traffic that routers use to communicate with each other. Dynamic routing simplifies administration since it eliminates the need to configure static routes. It also allows the router to communicate new routes to networks when a route becomes unavailable. Lastly it allows for the determination of the best route when multiple routes exist.

What is media access control? How is it used in full-duplex, half-duplex, point-to-point, and multi-point configurations?

Media access control (MAC sublayer) controls the physical hardware. It refers to the need to control when computers transmit. With point-to-point full-duplex configurations, media access control is unnecessary because there are only two computers on the circuit, and full duplex permits either computer to transmit at any time. Thus, media access control is not very important in point-to-point with full duplex configuration

Be able to describe RIP and RIPv2

RIP and RIPv2. RIP and RIPv2 are distance vector routing protocols

Which of the following are considered link state routing protocols?

OSPF and IS-IS are link state.

What happens once a router determines the interface to which it should send a packet?

Once a router determines the interface to which it should send a packet it performs an arp broadcast only on the destination network to learn the MAC address of the destination computer. It cannot send the packet until it learns the MAC address, which must be known for all communication within the same network. It is not necessary, nor will it perform an arp broadcast on all networks to learn the MAC address of the destination computer. It will perform the broadcast only on the destination network. It also will not query all other routers for the MAC address of the destination computer, as other routers will not know this information if the destination network is local to the router

What does the term, peak circuit traffic, mean?

Peak circuit traffic is an estimate of the highest data volume on a link.

Define polling

Polling is the process of sending a signal to a client that gives its permission to transmit or asks it to receive

Users on your network are saturating your bandwidth because they are using too many non-work-related sites. What device would limit the availability of the types of sites that users on a LAN have access to while providing granular control over the traffic between the local LAN and the Internet?

Proxy server -A proxy server can provide many functions. A proxy server can use a caching engine so repeated access requests for web information would accelerate repeated access for users, and they can also limit the availability of websites.

With regard to RIP, which of the following statements are true?

RIP send the entire routing table to its neighbor every 30 seconds. One of the disadvantages of the RIP routing protocol is the additional network traffic it generates by sending the entire routing table to its neighbors every 30 seconds. It does not have the ability (like some other routing protocols do) to send only the changes to the routing table.

You need to have a connection to run applications that are installed on only your desktop computer at your office. Which protocol will provide a GUI interface to your work computer?

Remote Desktop Protocol (RDP) allows you to connect to a remote computer and run programs, as Telnet does. However, the large advantage that RDP has over Telnet is that RDP allows you to have a GUI interface connection.

Your network is divided into two segments. As the signal travels down the first segment, it becomes weak. To amplify the signals passing to the second segment, the network engineer installed a networking device. Which networking device did the engineer install?

Repeaters are network devices that amplify data signal and all accompanying noise. Network devices that connect segments are bridges and hubs. Routers connect network subnets. A bridge connects different segments of a network in order to expand the scope of the network. Bridges filter data on a network by MAC address to isolate traffic on a network segment. A gateway is an internetworking device used to connect networks that use different protocols. The gateway is used as a protocol translation device. Modems (modulator/demodulators) are devices that convert the digital signal that a computer understands to an analog signal that can be transmitted over a traditional telephone line

What does RFP stand for?

Request for Proposal

What performs server name resolution?

Server name resolution is done using the Domain Name Service

What is an effective way to prevent impulse noise, cross talk, and intermodulation noise?

Shielding wires is an effective way to prevent impulse noise, cross talk, and intermodulation noise

You want to connect Network X to Network Y creating an internetwork. Which internetworking device should you use to accomplish this?

Router. A internetwork is a network composed of individual, independent networks connected by internetwork connectivity devices. The independent networks maintain their own identities even though they are connected within an internetwork. The largest internetwork in common use is the Internet. Traditional internetwork connectivity devices are routers, brouters, and CSU/DSUs-(channel service units/digital service units). Routers connect network subnets

Define the term, routing.

Routing is the process of determining the path that a message will travel from sending computer to receiving computer.

You need to log in to a Unix server across a network that is not secure. Which of the following protocols will allow you to remotely administrate this server securely?

Secure Shell (SSH) allows you to remotely administer router, switches, and even servers securely

How is simulation used in network design?

Simulation is used to model the behavior of the planned communication network once the proposed network map is complete

What is the primary source of error in data communications?

Spikes

What device creates separate collision domains and a single broadcast domain?

Switches create separate collision domains but a single broadcast domain. Remember that routers provide a separate broadcast domain for each interface

What is the purpose of ACL?

The ACL defines what type of packets should be routed and what types of packets should be discarded.

Using the illustration below, what would be the IP address of E0 if you were using the first subnet?

The network ID is 192.168.10.0/28, and you need to use the last available IP address in the range. Again, the zero subnet should not be considered valid for this question

With respect to EIGRP which of the following tables contains all destinations advertised by neighboring routers?

The topology table contains all destinations advertised by neighboring routers. The neighbor table is a list of all neighboring routers. The routing table contains only the best routes. There is no MAC table. Those exist only on switches

What are the sublayers of the data link layer?

The two sublayers of the data link layer consist of the media access control sublayer and the logical link control sublayer

What is the purpose of port numbers? Which of the following allows a server to distinguish among different simultaneous requests from the same host?

They use different port numbers. Through the use of port numbers, TCP and UDP can establish multiple sessions between the same two hosts without creating any confusion. The sessions can be between the same or different applications, such as multiple web-browsing sessions or a web-browsing session and an FTP session.

What is an anycast address?

This address identifies multiple interfaces, and the anycast packet is delivered to only one address; the closest one. This address can also be called one-to-nearest. Anycast addresses identify multiple interfaces, which is the same as multicast; however, the big difference is that the anycast packet is delivered to only one address: the first one it finds defined in terms of routing distance. This address can also be called one-to-one-of-many or one-to-nearest

When more than one application program is using the same communications line, what does the TCP/IP rely on to decide which application program a message should be delivered? Assume that more than one application program is using the same communications line on a particular computer.

To be able to decide to which application program a message should be delivered on this computer, TCP/IP relies on the: port address

How is circuit loading established? What does the designer start with first?

To establish circuit loading, the designer usually starts with the total characters transmitted per day on each circuit, or, if possible, the number of characters transmitted per two-second intervals if peaks must be met.

What is the formula used to calculate the number of subset bits required to yield a required number of subnets?

What is the formula used to calculate the number of subnet bits required to yield a required number of subnets? 2n =X, where n = number of subnet bits and X = number of networks

How do you calculate throughput?

What needs to be considered when calculating actual throughput? Throughput is the total number of information bits received per second, after taking into account the overhead bits and the need to retransmit frames containing errors. Calculating the actual throughput of a data communication network is complex because many factors affect throughput.

Understand what happens during the server name resolution. Make sure you understand the role of the DNS request packet and DNS response packet.

When TCP/IP translates an application layer address into an IP address, it sends a special DNS request packet to the nearest DNS server.

What is multicasting? Distinguish between a unicast message and a multicast message.

When a computer sends a message to another computer this is called a unicast message. A special type of message that is used when sending the same message to a specific group of computers is called a multicast message.

Distinguish between static and dynamic routing.

When a router learns routes to remote networks from other routers in the network it is known as dynamic routing. When an administrator manually configures the routes at the command line it is known as static routing. Interior Gateway Protocol (IGP) refers to any type of routing that occurs within the same autonomous system (usually the same company), so it includes both static and dynamic. Exterior Gateway Protocol EGP) refers to any type of routing that occurs between autonomous systems.

What happens when a router receives a packet to a remote network that is not listed in its routing table?

When a router receives a packet to a remote network that is not listed in the routing table, it discards the packet and sends an ICMP message to the transmitting device. It will not query other routers for a route. It will also not simply discard the packet without notifying the sending device with an ICMP message. Finally a router only performs an arp broadcast to learn the MAC address of the destination computer when it receives a packet from a remote network destined for a computer on the local network.

Define echoes

When a signal is reflected back to the transmitting equipment, it is calls an echo

Describe a discontiguous network.

When two or more subnetworks of a classful network are connected together by different classful networks it is known as discontiguous networks. This arrangement requires the use of classless routing protocols or those that send the subnet mask in updates. It is not when two or more subnetworks of a classless network are connected together by different classless networks. It is also not when networks learned from different protocols are in the routing table, nor is it a description of when a router capable of classless routing updates a router only capable of classful routing.

With respect to EIGRP, which type of route will be placed in the routing table?

With respect to EIGRP, there are two types of routes, both of which can be found in the topology table. Successor routes are the best routes and are placed in the routing table. Feasible successors are the second best routes and are kept in the topology table for fast reference if the successor route becomes unavailable. There are no EIGRP route types referred to as VLSM or backbone routes

Your network is connected to the Internet. As the network administrator, you install packet filtering on the router that connects your network to the Internet. After you configure packet filtering, users on the network are no longer able to send email outbound to the Internet. What did you do to create this problem?

You blocked port 25. Packet filtering is the process of filtering (discarding) data based on source address, destination address, port number, or domain name. Packet filtering is a software implementation of a firewall.

How can you perform maintenance on a router and still ensure the network doesn't go down?

You need to perform maintenance on a router in your corporate office. It is important that the network does not go down. What can you do to accomplish your goal? Configure on the router a static route that temporarily reroutes traffic through another office. The best answer would be to reroute traffic using a temporary static route until the maintenance is complete on the router.

Distinguish between the different types of routing.

a. Centralized routing - all routing decisions are made by one central computer or router. b. Static Routing - decentralized, which means that all computers or routers in the network make their own routing decisions following a formal routing protocol. c. Dynamic Routing (adaptive routing) - routing decisions are made in a decentralized manner by individual computers. i. Distance vector routing - With distance vector routing, computers or routers count the number of hops along a route and periodically exchange information on the hop count with their neighbors. (Q92) ii. Link state dynamic routing - computers or routers track the number of hops in the route, the speed of the circuits in each route, and how busy each route is.

Be familiar with Internet addresses, including IPv4 public address space, IPv4 private address space, reserved addresses, classless addressing, and addresses reserved for loopback, multicasting, and broadcast messages.

a. IP addresses from 224 to 239 belong to Class D and are reserved for multicasting. (Q20) b. The 127 address range is reserved for a computer to communicate with itself and is called the loopback.

Distinguish between the following Internet Layer Protocols: IP, ICMP, ARP, and RARP.

a. Internet Protocol (IP) is essentially the Internet Layer (p. 189) b. Internet Control Message Protocol (ICMP) works at the Network layer and is used by IP for many different services. (p. 190) c. What protocol is used to find the hardware address of a local device? ARP. Address Resolution Protocol (ARP) is used to find the hardware address from a known IP address. (Q96) d. Reverse Address Resolution Protocol (RARP) discovers the identity of the IP address for diskless machines by sending out a packet that includes its MAC address and a request for the IP address assigned to that MAC address.

What are the major steps used in the building-block process to network design? Distinguish between the major steps.

a. Needs analysis (1st step) - designer attempts to understand the fundamental current and future network needs of the various users, departments, and applications. b. In the Technology Design step (2nd step) of the building-block process to network design, the network designer examines the available technologies and assesses which options will meet the users' needs. (Q16) c. Cost assessment (3rd step) - relative costs of the technologies are considered. d. Knowing the above 3 steps, you will be able to answer: Which of the following is not one of the three major steps used in of the building-block process to network design?

Distinguish between the different types of noise.

a. The familiar background static on radios and telephones is call white noise. b. If a signal with a frequency of 500 MHz combines with another signal of 1500 MHz and they form a new signal of 2000 MHz; this is an example of intermodulation noise. c. Impulse noise (spikes) is the primary source of errors in data communications. d. Cross-talk occurs when one circuit picks up signals in another. e. Echoes are the result of poor connections that cause the signal reflect back to the transmitting equipment. f. Attenuation is the loss of power a signal suffers as it travels from the transmitting computer to the receiving computer.

Distinguish between the different components of a network architecture.

a. The network architecture component which enables users to access the network is the LAN (Q65) b. Building backbone network (distribution layer) - distributes network traffic to and from the LANs. c. Campus backbone (core layer) - connects all the buildings on one campus. d. Data center - contains the organization's servers. e. Enterprise Edge Components: i. WAN ii. Internet Access iii. The network architecture component that is a special LAN with a group of servers that enables electronic data exchange of between the organization and the external entities it does business with is called the e-commerce edge

Link State protocols

also called shortest path first protocols - the routers each create three separate tables.

Distance Vector protocols

find the best path to a remote network by judging distance. RIP, RIPv2, and IGRP are distance vector routing protocols

Given the decimal IP address, 128.1.1.254/20, what is the:

i. Address Class: B ii. Number of Subnet bits: 4 iii. Number of Host bits: 12 iv. Number of subnets: 16 v. Number of hosts for each IP address. 4094.

Given the decimal IP address (192.168.20.123/28), what is the

i. Address Class: C ii. Number of Subnet bits: 4 iii. Number of Host bits: 4 iv. Number of subnets: 16 v. Number of hosts for each IP address. 14.

What are costs generally considered during the cost assessment stage of the building-block network design process?

internetworking devices cost, network management costs, circuit costs, software costs for network operating system.

What are two ways to ping a loopback address?

ping 127.0.0.1, ping::1. The loopback address with IPv4 is 127.0.0.1. With IPv6, that address is ::1

Hybrid protocols

use aspects of both distance vector and link state. iBGP and EIGRP are hybrid protocols