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87 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What does the Application Layer do?
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The _______ layer provides file, print, message, database and application services. It is also responsible for finding the network resources broadcast from a server and adding flow control and error control if the application developer chooses.
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Layer 7 of the OSI model. FTP and TFTP actually reside here.
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What does the Presentation Layer do?
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The __________ layer provides data encryption and decryption, compression and decompression as well as translation services. This layer actually defines how data is formatted, presented, encoded and converted for use on the network.
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Layer 6 of the OSI model. EBCDIC to ASCII.
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What does the Session Layer do?
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The ___________ layer provides dialog control. This layer actually sets up, maintains and terminates sessions between applications. Coordinates communications between systems by offering three different modes: Simplex, Half-Duplex and Full-Duplex.
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Layer 5 of the OSI model. Basically keeps different application's data separate from other application's data.
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What does the Transport Layer do?
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The __________ layer provides a logical connection between sending and destination hosts (end-to-end connection,) reliable or unreliable delivery, error correction before retransmit, segmenting, sequencing and virtual circuits. Also helps control the flow of information through buffering, windowing and congestion avoidance.
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Layer 4 of the OSI model. Virtual Circuits!
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What does the Network Layer do?
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The ________ layer provides routing, logical addressing (which routers use for path determination)
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Layer 3 of the OSI model
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What does the Data Link Layer do?
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The _________ layer combines packets into bytes and bytes into frames, provides access to media using MAC address, performs error DETECTION/NOTIFICATION not correction and actually places the data on the network medium. Also handles network topology and provides flow control.
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Layer 2 of the OSI model. Network Topology!
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What does the Physical Layer do?
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The _______ layer moves bits between devices, specifies voltages, wire speed and pin-out of cables. It is responsible for the electrical and mechanical connection between devices.
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Layer 1 of the OSI model
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Why does the OSI model exist?
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The ____ model is used to help application developers design applications that can run on any type of system or network. It divides the network communication process into smaller and simpler components or layers and each layer has a special job. The OSI model encourages industry standardization.
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What are the possible causes of LAN congestion?
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What could happen if you had too many hosts in a broadcast domain, broadcast storms, multicasting, and low bandwidth?
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What is a Collision Domain?
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A _______ domain is an Ethernet term used to describe a network collection of devices in which one particular device sends a packet on a network segment, forcing every other device on that same segment to pay attention to it.
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What is a Broadcast domain?
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On a _______ domain a set of devices on a network segment hear all broadcasts sent on that segment.
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What is a Hub?
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What is known as a Multi port repeater? Layer 1 device that creates ONE collision domain and ONE broadcast domain.
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What is a Bridge?
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What type of device breaks up collision domains, but creates one broadcast domain? Layer 2 device.
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What is a switch?
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What layer two devices is known as a multi port bridge with more intelligence? Use hardware addresses to filter the network.
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What is a router?
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What layer three device breaks up broadcast domains, collision domains and uses logical addressing to filter the network?
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Sends and receives information about the Network Layer.
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Describe connection oriented network services
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_______-oriented services use acknowledgments and flow control to create a reliable session.
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What are the types of Ethernet Cabling & why would you use each?
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There are three types of Ethernet Cabling; straight through (PC or Router's Ethernet port to a switch or hub,) crossover (PC to PC, hub to hub, hub to switch or switch to switch,) and rolled (connects a host/PC to a router or switch's console port.)
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Straight;1=1,2=2,3=3,6=6
Crossover;1=3,2=6,3=1,6=2 Rolled;1=8,2=7,3=6,4=5,5=4, 6=3,7=2,8=1 |
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What are the names of the layers in Cisco's three-layer model?
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Core, Distribution and Access layers are the parts of what?
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Core=high volume of traffic both reliably and quickly. Switch as fast as possible. Fault tolerance is a huge issue here.
Distribution=Workgroup layer. Provides routing, filtering and WAN access. Determines how packets can access the core, if needed. This is where policies are implemented (access lists, packet filtering, security, NAT, firewalls, redistributing between routing protocols [such as static routing] VLAN routing, defining broadcast and multicast domains. Access Layer=Desktop layer. Collision domains, more access lists and policies, static routing and Ethernet switching are seen here as well. |
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What is a PDU?
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Protocol Data Units, or PDUs hold the control information during the encapsulation process of passing information down the OSI layers. At the Transport Layer, the information to be passed from the above layers (Application, Presentation and Session) is encapsulated into a Segment. Once at the Network layer the data is encapsulated into a Packet. At the Data Link layer the information is Framed for use on the physical layer, where it is just a series of 1's and 0's called Bits.
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Part of the Encapsulation process.
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What is the PDU at the Transport Layer?
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Protocol Data Units at the Transport Layer are called Segments
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Segments start with source PORT (not IP address or MAC address.)
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What is the PDU at the Network Layer?
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Protocol Data Units at the Network Layer are called Packets (think Packet Switching.)
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The network layer adds a header and the logical addressing (IP address first!) to the front of each segment and now the PDU is called a packet.
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What is the PDU at the Data Link Layer?
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Protocol Data Units at the Data Link Layer are called Frames.
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Information is added to both the Header and Trailer (sort of like bookends or FRAMES) and the first field is the MAC address...the last field is the checksum answer or FCS.
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What is the PDU at the Physical Layer?
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Protocol Data Units at the Physical layer are Bits!
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The frame from the DLL is literally handed down bit by bit to be sent along the media, then reassembled at the other end into a frame again.
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How many stages are there in the PDU flow of encapsulation? Name them.
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Data --> Segment --> Packet --> Frame --> Bit describes what process?
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Remember, the Data starts this process...not the segment. Data is SEGMENTED.
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What is the bit length and expression form of a MAC address?
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What is 48 Bits or 6 Bytes and expressed as a Hexadecimal number?
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Remember, it's two nibbles per byte!
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Where is Ethernet defined? (what layers)
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Data Link and Physical
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Name four router functions
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Packet switching, Packet filtering, Internetwork Communication and Path selection are four functions of what device?
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What are the types of Flow Control?
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Buffering, windowing and congestion avoidance are the types of what?
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There are three
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Where would you segment a data stream?
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The Transport Layer segments data streams from the upper layers.
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What is the purpose of Flow Control?
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_____ Control provides a means for the receiver to govern the amount of data sent by the sender.
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What is the Class A IP range in binary, and decimal?
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0.0.0.0 to 127.255.255.255
or in Binary 00000000. 00000000. 00000000. 00000000 to 01111111. 11111111. 11111111. 11111111 |
This INCLUDES the exceptions and private IP space because those are still Class A IP addresses, they're just not usable.
Binary, the first bit is always OFF in a class A IP address. |
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What is the Class B IP range in binary, and decimal?
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128.0.0.0 to 191.255.255.255
or in Binary 10000000. 00000000. 00000000. 00000000 to 10111111. 11111111. 11111111. 11111111 |
This INCLUDES the exceptions and private IP space because those are still Class B IP addresses, they're just not usable.
In Binary, a class B always has the FIRST bit ON and the SECOND bit OFF. |
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What is the range of a class C IP address in decimal and binary?
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192.0.0.0 to 223.255.255.255
or in Binary 11000000. 00000000. 00000000. 00000000 to 11011111. 11111111. 11111111. 11111111 |
This INCLUDES the exceptions and private IP space because those are still Class C IP addresses, they're just not usable.
In Binary, a class C IP address always has the FIRST TWO bits turned ON and the THIRD bit OFF. |
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What is the significance of a network address of all 0's?
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This is interpreted to mean "this network or segment" and is a reserved IP address.
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One of the reserved IP addresses
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What is the significance of a network address of all 1's?
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This is interpreted to mean "all networks" and is a reserved IP address.
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One of the reserved IP addresses
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What is the significance of the network address 127.0.0.1?
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Which address is reserved for Loopback testing? This allows a node to send a test packet to itself without generating network traffic.
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One of the reserved IP addresses
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What is the significance of a node address of all 0's?
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This is interpreted to mean "network address" or any host on a specified network.
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One of the reserved IP addresses
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What is the significance of a node address of all 1's?
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This is interpreted to mean "all nodes" on the specified network; e.g. 128.2.255.255 means "all nodes" on class B network address 128.2
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One of the reserved IP addresses
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What is the significance of an entire IP address set to 1's?
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This is equivalent to 255.255.255.255 and is broadcast to all nodes on the current network; sometimes called an "all 1's broadcast" or limited broadcast.
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One of the reserved IP addresses
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What is the significance of an entire IP address set to all 0's?
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Used by Cisco routers to designate the default route. Could also mean "any network."
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One of the reserved IP addresses
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Telnet
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What is a terminal emulation program that allows you to log into a remote host and run programs?
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This is a DOD model Process/Application layer protocol
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FTP (File Transfer Protocol)
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What is a connection-oriented service that allows you to transfer files.
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This is a DOD model Process/Application layer protocol
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TFTP (Trivial FTP)
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What is a connectionless file transfer program?
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This is a DOD model Process/Application layer protocol
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SMTP (Simple Mail Transfer Protocol)
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What is a send-mail program?
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This is a DOD model Process/Application layer protocol
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TCP (Transmission Control Protocol)
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What is a connection-oriented protocol that provides reliable network service by using acknowledgments and flow control?
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This is a DOD model Host-to-Host layer protocol
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UDP (User Datagram Protocol)
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What is a connectionless protocol that provides low overhead and is considered unreliable?
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This is a DOD model Host-to-Host layer protocol
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IP (Internet Protocol)
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What is a connectionless protocol that provides network addresses and routing through an internetwork?
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This is a DOD model Internet layer protocol
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ARP (Address Resolution Protocol)
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What finds a hardware address from a known IP address?
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This is a DOD model Internet layer protocol
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RARP (Reverse ARP)
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What finds an IP address from a known hardware address? (Resolves MAC address to IP address)
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This is a DOD model Internet layer protocol
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ICMP (Internet Control Message Protocol)
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What protocol provides diagnostics and "destination unreachable" messages?
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This is a DOD model Internet layer protocol
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What is the private IP range for the Class A addresses?
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What are 10.0.0.0 through 10.255.255.255?
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Private addresses are routed internally, apart from the internet, and only translated through NAT for internet traffic.
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What is the private IP range for the Class B addresses?
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What is in the range of 172.16.0.0 to 172.31.255.255?
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Private addresses are routed internally, apart from the internet, and only translated through NAT for internet traffic.
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What is the private IP range for the Class C addresses?
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What addresses are in the range of 192.168.0.0 through 192.168.255.255?
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Private addresses are routed internally, apart from the internet, and only translated through NAT for internet traffic.
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What layer of the DOD model is equivalent to the Transport layer of the OSI model?
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Host-to-Host is equivalent to what layer in the OSI model?
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Not the internet layer.
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What layer of the DOD model includes the Application, Presentation and Session layers of the OSI model?
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Process/Application layer
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Upper layer
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Proxy ARP
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Not really a separate protocol. Actually a service run by routers on behalf of other devices (usually PC's) that are separated from their query to another device by a router, although they THINK they share the same subnet with the remote device. Can be added to only ONE router. Is BY DEFAULT configured on all Cisco devices (turn it off if you're not using it for a savings in latency/traffic/ARP tables!)
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If you can afford it use Cisco's HSRP instead. Requires two (or more) of the Cisco device, but in terms of overhead, is well worth it.
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How do you find the network address from a listed IP address?
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Turn all the host bits off.
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97.0.0.0 is a host address
173.10.0.0 is a host address 194.165.251.0 is a host address |
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How do you find the broadcast address from a listed IP address?
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Turn all the host bits on.
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97.255.255.255 is a Class A broadcast address
173.10.255.255 is a Class B broadcast address 194.165.251.255 is a Class C broadcast address |
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What are the valid characters you can use in a hexadecimal address?
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0-9 and A, B, C, D, E, F where A=10, B=11, C=12, D=13, E=14 and F=15.
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Remember MAC addresses are in the Ethernet header and are 6 bits (12 nibbles), not 4 bits like an IP address
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What is DHCP?
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Dynamic Host Configuration Protocol assigns IP addresses to hosts. It allows easier administration and works well in small to even very large networks. All types of hardware can be used as a DHCP server, including a Cisco Router.
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DHCP is Dynamic BootP. DHCP is connectionless and uses UDP.
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What is DNS?
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Domain Name Service resolves hostnames, specifically Internet names, such as www.routersim.com.
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If you can PING a device with it's IP address, but cannot use it's FQDN, you have a DNS issue.
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What is SNMP?
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Simple Network Management Protocol collects and manipulates valuable network information. It gathers data by polling the devices on the network from a management station at fixed or random intervals, requiring them to disclose certain information.
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SNMP creates a BASELINE which is a report delineating the operational traits of a healthy network. Aberrations from this baseline are noted by running AGENTS which send alerts called TRAPS to the management station.
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What is SMTP?
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Simple Mail Transfer Protocol uses a spooled or queued method of mail delivery. Once a message has been sent to a destination it's SPOOLED to a device, usually a disk.
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POP3 is used to RECEIVE mail.
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What is X Window?
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Designed for Client/Server operations X Window defines a protocol for writing c/s apps based on a gui.
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The idea is to allow a program, called a client, to run on one computer and have it display things through a window server on another computer.
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What is LPD?
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Line Printer Daemon Protocol is designed for printer sharing. The LPD along with LPR (Line Printer) program, allows jobs to be spooled and sent to the network's printers using TCP/IP.
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What is FTP?
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File Transfer Protocol is not only the protocol used by applications to transfer files between any two machines using it, but it's also a program used to perform file tranfers by hand using a stand alone FTP server on the internet.
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FTP partners with Telnet to get you transparently logged in to the FTP server which then provides for the transfer of files.
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What is TFTP?
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The stripped down, stock version of FTP. Connectionless, unsecure, no directory browsing capabilities. Does nothing but send and receive files very quickly, in small chunks.
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Few sites support this because of it's inherent security risks.
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What is Telnet?
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The chameleon of protocols. It's specialty is terminal emulation. It allows a user on a remote client machine, called the Telnet client, to access the resources of another machine, the Telnet server. Telnet does this by emulating a local port on the destination machine so it's fooled into thinking the user is a terminal directly attached to the machine.
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This projection is actually a software image - a virtual terminal that can interact with the chosen host.
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What is NFS?
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Network File System is a jewel of a protocol specializing in file sharing. It allows two different types of file systems to interoperate.
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NFS allows a portion of the RAM on one device to hold data from the other file system in a comprehensible manner to the first file system. E.g. NT to Unix.
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List the DOD model's Process/Application layer's protocol suite
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Telnet, FTP, TFTP, LPD, SNMP, SMTP, NFS, X Window, DNS, DHCP.
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There are 10
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What layer 4 protocol is used for a Telnet connection?
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TCP.
NOT TCP/IP since IP is a layer 3 protocol. |
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What is ICMP?
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Internet Control Message Protocol works at the Network layer and is used by IP for many different services. ICMP is a management protocol and messaging service provider for IP. ICMP messages are carried as IP datagrams.
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Common events and messages ICMP relates to:
Destination Unreachable Buffer Full Hops Ping (Packet Internet Groper) Traceroute (ICMP Timeouts) |
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/25
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128 mask or (255.255.255.128)
1 bit ON and 7 bits OFF (10000000) Block size of 128 2 subnets, each with 126 hosts |
Subnet________0 128
First Host______1 129 Last Host______126 254 Broadcast______127 255 |
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/26
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192 mask (255.255.255.192)
2 bits ON and 6 bits OFF (11000000) Block size of 64 4 subnets, each with 62 hosts |
Subnet________0___64 128 192
First Host______1___65 129 193 Last Host______62__126 190 254 Broadcast______63__127 191 255 |
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/27
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224 mask (255.255.255.224)
3 bits ON and 5 bits OFF (11100000) Block size of 32 8 subnets, each with 30 hosts |
Subnet________0___32...192 224
First Host______1___33...193 225 Last Host______30__62...222 254 Broadcast_____31__63...223 255 |
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/28
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240 mask (255.255.255.240)
4 bits ON and 4 bits OFF (11110000) Block size of 16 16 subnets, each with 14 hosts |
Subnet________0___16...224 240
First Host______1___17...225 241 Last Host______14__30...238 254 Broadcast_____15__31...239 255 |
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/29
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248 mask (255.255.255.248)
5 bits ON and 3 bits OFF (11111000) Block size of 8 32 subnets, each with 6 hosts |
Subnet________0___8...240 248
First Host______1___9...241 249 Last Host______6__14...246 254 Broadcast______7__15...247 255 |
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/30
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252 mask (255.255.255.252)
6 bits ON and 2 bits OFF (11111100) Block size of 4 64 subnets, each with 2 hosts |
Subnet________0___4...248 252
First Host______1___5...249 253 Last Host______2__6...250 254 Broadcast______3__7...251 255 |
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In subnetting, what are the big 5?
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1) How many subnets does the chosen subnet mask produce?
2) How many valid hosts per subnet are available? 3) What are the valid subnets? 4) What's the broadcast address of each subnet? 5) What are the valid hosts in each subnet? |
1) 2^x where x=# of masked bits (or the 1's)
2) 2^y - 2 where y=# of unmasked bits (or the 0's) 3) 256-Subnet mask = Block size (start counting at 0 in increments of your block size until you get to your subnet mask and these are your subnets.) 4) Easy one. It's always 1 before or below the Subnet 5) The numbers between the subnets, omitting the all 0's and all 1's. |
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List the valid Class C subnets with binary, digital and CIDR notation for each
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Binary______Digital___CIDR ___ Subnets
00000000 = ___0______/24 ___ 0 10000000 = ___128____/25 ___ 2 11000000 = ___192____/26 ___ 4 11100000 = ___224____/27 ___ 8 11110000 = ___240____/28 ___ 16 11111000 = ___248____/29 ___ 32 11111100 = ___252____/30 ___ 64 |
We can't use a /31 or /32 because we have to have at least two host bits for assigning IP addresses to hosts.
This ASSUMES the ip subnet-zero command has been used! |
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List the valid Class A subnets (chart will include all Class B and Class C subnets as well...these are those EXCLUSIVE to Class A.)
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Binary______Digital___CIDR
00000000 = ___0______/8 10000000 = ___128____/9 11000000 = ___192____/10 11100000 = ___224____/11 11110000 = ___240____/12 11111000 = ___248____/13 11111100 = ___252____/14 11111110 = ___254____/15 |
Subnet Mask
255.0.0.0 255.128.0.0 255.192.0.0 255.224.0.0 255.240.0.0 255.248.0.0 255.252.0.0 255.254.0.0 |
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List the valid Class B subnets (these are also usable as Class A subnets.)
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Binary______Digital___CIDR
00000000 = ___0______/16 10000000 = ___128____/17 11000000 = ___192____/18 11100000 = ___224____/19 11110000 = ___240____/20 11111000 = ___248____/21 11111100 = ___252____/22 11111110 = ___254____/23 |
Subnet Mask
255.255.0.0 255.255.128.0 255.255.192.0 255.255.224.0 255.255.240.0 255.255.248.0 255.255.252.0 255.255.254.0 |
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Define Classful subnetting, including the steps you need to take in order to create a subnet.
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1) Determine the number of Network IDs:
__1a) One for each subnet __1b) One for each Wide Area Segment 2) Determine the required number of host IDs per subnet: __2a) One for each TCP/IP host __2b) One for each router interface 3) Based on the above requirements, determine the following: __3a) One subnet mask for your entire network __3b) A unique subnet ID for each physical segment __3c) A range of host IDs for each subnet |
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What are the default subnet masks for each class?
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Class _____ Format
___ A ___ Network.Node.Node.Node ___ B ___ Network.Network.Node.Node ___ C ___ Network.Network.Network.Node |
Default Subnet Mask
255.0.0.0 255.255.0.0 255.255.255.0 |
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Practice counting by 16, 32 and 64.
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16: 0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240.
32: 0, 32, 64, 96, 128, 160, 192, 224. 64: 0, 64, 128, 192. |
Memorize
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Learn the power of 2's up through 2^16.
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2^1 = 2
2^2 = 4 2^3 = 8 2^4 = 16 2^5 = 32 2^6 = 64 2^7 = 128 2^8 = 256 2^9 = 512 2^10 = 1024 2^11 = 2048 2^12 = 4096 2^13 = 8192 2^14 = 16384 2^15 = 32768 2^16 = 65536 |
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Memorize the VLSM Block sizes chart for /25 through /30
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Prefix _ Mask _ Hosts _ Block Size
_ /25 _ 128 _ _ 126 _ _ 128 _ /26 _ 192 _ _ 62 __ _ 64 _ /27 _ 224 _ _ 30 __ _ 32 _ /28 _ 240 _ _ 14 __ _ 16 _ /29 _ 248 _ _ 6 ___ _ 8 _ /30 _ 252 _ _ 2 ___ _ 4 |
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