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CCNA1

By Brian Campbell,2014-08-30 09:32
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CCNA1

    Cisco Certified Network Associate Study Guide

    ; Interoperability involves making sure that the data can be understood by equipment manufactured

    by different vendors that use different operating systems, hardware or languages. ; The data rate range for X.25 is from 9.6 Kbps to 256 Kbps.

    ; IBM's Token Ring specification is nearly identical and compatible with IEEE's 802.5 specification. ; OSI stands for Open Systems Interconnection

    ; The three switching modes included in Catalyst 1900/2820 switches are: fastforward, fragmentfree,

    and store and forward.

    ; A backoff algorithm is used to prevent two nodes from retransmitting simultaneously and creating

    an endless number of collisions by delaying the retransmission for a variable length of time on

    each node.

    ; A Network Control Protocol frame in a Point to Point Protocol is used for selecting and configuring

    the network layer protocol. A Link Control Protocol (LCP) is used to establish and configure a

    connection.

    FDDI specifies protocols at both the MAC sublayer and the physical layer of the OSI reference

    model.

    ; In a Token Ring network architecture, what does it mean when a node possesses a token? When

    a node receives the token, if the node has data to transmit, it flips a bit in the token and transmits

    the data. If the node has no data to transmit, it sends the token to the next node. ; What two types of frames are found on a Token Ring network? There is a token frame and a data

    frame used on a Token Ring network.

    ; A Frame Check Sequence (FCS) in the IEEE 802.3 frame includes a CRC value.

    ; “plntspa” – plant spa is the reverse order of the layers of the OSI model.

    ; Which statements are true of a preamble in the IEEE 802.3 frame? The preamble is an indication

    of the start of a new frame. It contains alternating zeroes and ones.

    ; The session layer is usually implemented in the software. The physical and data link layers are

    usually implemented in hardware and software. The remaining layers are usually implemented in

    the software.

    ; Data Link Connection Identifier in a Frame Relay network identifies a connection between two

    DTEs.

    ; Hardware addresses are defined at the MAC portion of the data link layer.

    ; RS-232 is an extremely common serial port interface.

    ; Beaconing is a Token Ring mechanism for notifying other stations that a serious error has

    occurred on the network.

    ; The ITU X.25 Standard applies to the physical, data link, and network layers' protocols. ; The maximum data transmission rate for HSSI is 52 Mbps.

    ; The two header formats in ATM terminology are: User Network Interface (UNI) and Network Node

    Interface (NNI).

    ; Out-of-band management is network fault tolerant, because it can manage a switch or hub even

    when network services are interrupted.

    ; The data rate range for X.25 is from 9.6 Kbps to 256 Kbps.

    ; In a Frame Relay network, which statement is true of Forward Explicit Congestion (FECN) when

    the network is congested? Both FECN and Backward Explicit Congestion (BECN) contain a bit

    that is set to "1" and is sent by DTE to upper protocol layers to notify of traffic congestion between

    source and destination.

    ; In a Cisco router, configuration register information can be used to select a boot source and

    default file name, enable booting from a TFTP server, and load operating software from ROM. ; The command SHOW CDP NEIGHBOR DETAIL will show the IOS version. CDP does not need

    an IP address to run, it can use MAC.

     1

; The configuration register has 16 bits.

    ; What is the sequence of events that occurs when you power up your router? The router first tests

    its hardware, then attempts to locate and load an IOS image, and finally locates and applies its

    specific configuration information.

    ; The SHOW STARTUP-CONFIG will show the configuration stored in NVRAM. The SHOW

    RUNNING-CONFIG will show the configuration currently running.

    ; A good connection is indicated by which of the following in an output display of the PING

    command? A series of exclamation points (!!!!!) indicates a good connection. A series of dots (…..)

    indicates that the pings timed out.

    ; IOS image is usually stored in Flash and booted from Flash. RAM stores routing tables and the

    running configuration. NVRAM is for the startup configuration.

    ; The boot field set to 0x1 will cause the router to boot from ROM.

    ; The command history buffer will allow you to paste in your last 10 commands. This can be

    changed with the command HISTORY SIZE X.

    ; To suspend a Telnet session, use the keystrokes CTRL-SHIFT-6 x.

    ; The response to the command ROUTER# CONFIGURE ? will be a list of possible options from

    where the router can be configured.

    ; The boot field is the lowest four bits of the configuration register.

    ; If a mistake is made in specifying the file name in the COPY TFTP FLASH command, the router

    will still function because it still has working image in RAM.

    ; The router will try to resolve an incorrect command to an IP address, thinking it is a hostname, so

    it can establish a Telnet session with it.

    ; You would use either LOGOUT or EXIT to log out of the router and end your session. ; The configuration register setting is at the last line of the SHOW VERSION command. This

    command also shows router up time and IOS version.

    ; CTRL-Z will get the user completely out of the configuration mode. EXIT takes the user back one

    step. LOGOUT terminates your session.

    ; TERMINAL MONITOR sends Debug output to the VTY session.

    ; The command executive is the part of the IOS software that provides the user interface and

    interprets the commands you type. The configuration register is a memory location in NVRAM

    that controls the router's operation as it boots up.

    ; You must have an IP address assigned to an Interface in order for CDP to operate? False. CDP

    will multicast to a functional MAC address. There is no need to have any network layer address

    assigned to the interface to get the CDP messages to go out.

    ; Supernetting removes some of the rightmost bits of the default subnet mask, which summarizes

    several contiguous Class C networks into a single network entity.

    ; “ROUTER# PING” Extended ping requires Privileged mode, and also requires that no command-

    line options be entered (because it prompts for each option).

    ; To configure a name-to-address mapping in the router mapping table, you would issue which of

    the following commands? ROUTER(CONFIG-IF)# IP HOST or ROUTER(CONFIG)#IP HOST ; The significance of the address 3.255.255.255 is that it is a directed broadcast to network 3.0.0.0.

    A host number cannot have all ones. A local broadcast would have all ones (for example,

    255.255.255.255). While this is not a legal host address, it is perfectly valid as a broadcast

    address.

    ; Class D subnet masks are used for multicasting purposes.

    ; What IOS command turns off name-to-address resolution? ROUTER(CONFIG)# NO DOMAIN-

    LOOKUP

    ; Which of the following statements is true regarding IP host addresses? The subnet address part of

    an IP address can not be set to "all binary ones" or to "all binary zeros". ; The value 24 after / in the IP address 135.120.25.20/24 is called a prefix.

     2

    ; Subnet bits are taken from the highest-order contiguous bits of the host address in order to add

    subnets and/or reduce the number of hosts.

    ; A Class D network is used for multicasting, not for normal IP network/host addressing, so it

    doesn't have a default subnet mask.

    ; Up to six name server addresses can be specified using the ROUTER(CONFIG)# IP NAME-

    SERVER command.

    ; Given a subnet address of 5.32.0.0 and a subnet mask of 255.224.0.0, what is the highest allowed

    host address on this subnet? 5.63.255.254

    ; If we saw the following subnet addresses, what would be the subnet mask associated with these

    subnets? 140.120.4.0 | 140.120.8.0 | 140.120.12.0 | 140.120.16.0 - 255.255.252.0

    ; The IOS command you would use to define a global format to view the subnet mask during the

    "current session" is ROUTER # TERM IP NETMASK-FORMAT.

    ; Subnet bits are added to the default subnet mask to segment the network into subnets. ; A user on a Washington DC network receives the following response after issuing a router

    command: Tracing the route to Honolulu 1Tokyo(127.893.81.2) 800 ms 6 ms 4 ms 2

    Lisbon(141.925.64.7) 600 ms 8 ms 6 ms Honolulu(151.666.59.4) 400 ms 10 ms 8 ms Washington

    dc# This response was most likely obtained by issuing the command: WASHIGNGTONDC#

    TRACE HONOLULU

    ; We do not assign IP addresses to terminal lines. The terminal lines include the console, auxiliary

    port, and virtual terminal lines 0 - 4, which are used to configure the router. IP addresses are

    assigned to the interfaces on the router.

    Telnet is the only command that would test all layers of a protocol up to the application layer. ; The leading bit pattern 1111 is associated with Class E addresses, which range from 240-254 in

    the first octet.

    ; The Class D addresses have bit pattern which begins with 1110. This allows values from 224 -

    239 to be assigned for the purpose of multicasting.

    ; The purposes of subnetting are to segment and organize a single network at the network layer. ; VLSM allows us to use different subnet masks in different parts of the network and to divide a

    subnet into secondary subnets.

    ; A socket is an IP address plus a port

    ; TLI (transport layer interface) makes the transport layer independent from upper-layer services

    and represents a System V (API) Application Programming Interface.

    ; NetBIOS functions at the OSI model session layer.

    ; Windowing is a form of flow control at the transport layer.

    ; IP (Internet Protocol) is the network layer protocol that moves data from one node to another. ; The urgent pointer is not a part of the UDP header. The UDP header has only four parameters:

    source port, destination port, length, and UDP checksum.

    ; With ARP, an administrator does not have to physically manage the MAC address of each NIC.

    ARP separates routing function from the physical and data link layers.

    ; WinSock is a Microsoft Windows version of sockets.

    ; The transport layer is the single most important layer in assuring reliable data transfer regardless

    of the underlying networks in between the TCP/IP protocol suite.

    ; RARP is used by a system to resolve its IP address from the known MAC address. ; A port is where upper-layer processes access the transport layer.

    ; The spanning-tree algorithm allows for the prevention of duplication of forwarding of packets and

    forwards packets in a controlled manner.

    ; ICMP Redirect is sent by a gateway to the host. It instructs the host to use a different route when

    the router detects that its route is not as optimal as that of another router. ; The TCP/IP protocol suite does not have a formal session layer.

    ; RPCs provide transparency to make remote calls look local, and portability of applications

    between heterogeneous systems. RPC is a connectionless session.

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    ; ARP is a broadcast protocol, and ARP caching is used because broadcasts are expensive.

    Distributed Computing Environment (DCE) is an example of and RPC implementation. ; Which statement is true of WinSock? It provides the means for sharing an Internet connection

    between multiple IP protocol suite utilities

    ; NetBIOS can run over IPX, IP, and NetBEUI but not AppleTalk.

    ; Sockets allow multiple applications to use the same TCP/IP connection.

    ; Inverse Address Resolution Protocol (InARP) is generally used by nonbroadcast networks such as

    Frame Relay.

    ; The TCP/IP protocol suite has four layers.

    ; ICMP, IP, ARP, and RARP all map to OSI layer 3.

    ; Fragmentation is a process that occurs on a router somewhere between the source and

    destination. This process segments the datagram into a convenient size to fit into a single frame

    for transport over the network.

    ; If an intermediate node such as a router becomes congested, there is no mechanism defined that

    can notify TCP.

    ; The sequence number in a TCP header is used for acknowledgments, for reordering of the octets

    received, and for rejecting duplicate octets.

    ; What is SMTP's transport layer protocol port? TCP/23

    ; UDP and TCP represent mechanisms used by which layer of the TCP/IP? Transport Layer. ; What layers do not exist in the TCP/IP model that are in the OSI model? Presentation, session,

    and data link.

    ; IGRP is a distance vector and Interior Gateway Protocol with a 224 maximum network diameter

    (maximum 224 hops).

    ; The two mechanisms that make up a routing protocol are selecting the best route and transmitting

    the data

    ; Aging in a distance vector routing algorithm is set for all routing information.

    ; How can the administrator change how IGRP selects routes? The administrator can adjust the

    metric weights used for determining the route selection

    ; Routing updates are the method used to maintain the routing table.

    ; A route is removed from the routing table after seven update periods. In IGRP, updates are

    broadcast every 90 seconds. After three update periods where a route is missed, the route is

    considered unreachable. After seven periods, the route is removed.

    ; Low overhead of a routing algorithm is normally associated with CPU usage, and bandwidth.

    Accuracy is associated with optimal route.

    A default route is normally a type of static route that can be known as the gateway of last resort,

    where all nonroutable packets are forwarded to for further handling.

    ; The maximum number of hops used in EIGRP is 224.

    ; RIP authentication command can be used only with RIP version 2.

    ; In a hybrid network, the nonroutable packets are routed to a static router designated a router of

    last resort.

    ; For larger or complex networks, if the holddown period is made sufficiently large, then problems

    associated with the network stability could be minimized, though not eliminated in all cases. ; In a Frame Relay network, which statement is true of Forward Explicit Congestion (FECN) when

    the network is congested?

    ; Both FECN and Backward Explicit Congestion (BECN) contain a bit that is set to "1" and is sent by

    DTE to upper protocol layers to notify of traffic congestion between source and destination. ; OSI stands for Open Systems Interconnection

    ; The presentation layer of the OSI reference model is concerned with data formats, syntax and

    encryption.

    ; The maximum data transmission rate for HSSI is 52 Mbps.

    ; The ITU X.25 Standard applies to the physical, data link, and network layers' protocols.

     4

; DIX (Digital, Intel, and Xerox) co-created Ethernet.

    ; To turn off name-to-address resolution, the NO DOMAIN-LOOKUP command is issued from the

    global command prompt.

    ; The invalid subnet ID is 200.0.16.0. This represents an ID where all the subnet bits are zero. ; The significance of the address 3.255.255.255 is that it is a directed broadcast to network 3.0.0.0.

    A host number cannot have all ones. A local broadcast would have all ones (for example,

    255.255.255.255).

    ; To configure a name-to-address mapping in the router mapping table, you would issue which of

    the following commands? ROUTER(CONFIG-IF)# IP HOST or ROUTER(CONFIG)#IP HOST ; A Class D network is used for multicasting, not for normal IP network/host addressing, so it

    doesn't have a default subnet mask.

Chapter 1

Layer 7 Application

     Identify and establish the availability of the intended communication partner, and determine if sufficient resources exist for the communication.

Layer 6 Presentation

     Data compression, decompression, encryption, and decryption are presentation layer. Presentation layer standards include MPEG, MIDI, PICT,TIFF, JPEG, ASCII, and EBCDIC.

Layer 5 Session

     Dialog control between devices or nodes. Organizes the communication through simplex, half and full duplex modes. Deals with connection establishment, data transfer, and connection release. Protocols include NFS, SQL, RPC, Appletalk Session Protocol (ASP) and X Windows.

Layer 4 Transport

     Handles multiplexing upper-layer applications, session establishment and tear down of virtual circuits. Hides details of network dependent info from the higher layers by providing transparent data transfer. The “window” works at this level to control how much information is transferred before an acknowledgement.

Layer 3 Network

     Sends data from the source network to the destination network. The router will use packet switching to move a packet from one interface of port, to another through the network cloud.

Layer 2 - Data Link MAC & LLC

     Translates messages from the upper layers into data frames and adds customized headers containing the hardware destination and source address.

     Logical Link Control Sublayer Acts as a managing buffer between the upper layers and

    the lower layers. Uses Source Service Access Points (SSAPs) and Destination Service Access Points (DSAPs) to help the lower layers talk to the Network layer. Responsible for timing, and flow control.

     Media Access Control Sublayer Builds frames from the 1‟s and 0‟s that the Physical layer picks up from the wire as a digital signal, and runs Cyclic Redundancy Checksum (CRC) to assure that nothing was damaged in transit.

     Media Access Types Contention, Token Passing, and Polling.

     5

Layer 1 Physical

     Sends and receives bits. Communicates directly with communication media.

    Layer 2 WAN Protocols (Data Link Layer) How frames are carried between systems on a single data link.

    High Level Data Link Control (HDLC) default protocol for all Cisco serial links. Won‟t talk to

    another vendors HDLC.

    Synchronous Data Link Control (SDLC) designed to work with mainframes and remote offices,

    uses polling media-access. The front-end primary polls the secondaries to determine if they need

    to communicate.

    Link Access Procedure, Balanced (LAPB) Detects out of sequence frames and was designed for

    X.25.

    X.25 Point-to-point communication between DTE and DCE and supports Switched and

    Permanent Virtual Circuits. Cisco routers (DTEs) connect to modems or CSU/DSUs (DCEs).

    Serial Line IP SLIP is an industry standard for low speed serial interfaces.

    PPP Adds login, password, and error correction capabilities and is used by IP, IPX, and

    Appletalk.

    Frame Relay upgrade from X.25 and replaces need for LAPB. High quality digital from telco.

    Repeaters work at the Physical Layer and boost the signal to alleviate attenuation. Bridges work at the MAC sublayer of Datalink and forwards data to the network segment with the correct MAC address. Runs at Full Duplex, and can cause Broadcast Storms due to forwards to all attached networks when a broadcast. Bridges cannot read network numbers.

    Routers filter by both hardware and network address. Only forward packets to the network segment it is destined for.

    Data Encapsulation is process where info is wrapped in the data section of another protocol in the chain of Layers. Each layer encapsulates the layer immediately above it as data flows down the protocol stack.

    802.2 = SAP

    802.3 = Novell-Ether (default)

    Ethernet_II = ARPA

    Snap = Token_Snap, FDDI_Snap, etc.

    Destination MAC address is FFFFFFFFFFFFFFFF for a broadcast.

    ATM uses 53-byte fixed size cells instead of frames. Can allocate bandwidth on demand. SVC Switched virtual circuit that is dynamically created and torn down after transmission.

Which layer defines bit synchronization?

    Layer 1, the Physical Layer. Sets up the specifications for activation and maintaining the

    physical link between layers

The two sublayers of the IEEE Data Link layer are which of the following?

    At Layer 2, Logical Link Control and Media Access Control

Which layer defines the physical topology?

    Layer 1 Physical controls topology.

Which of the following are Session layer standards?

    Session Layer includes NFS and SQL.

What is the Network layer of the OSI reference model responsible for?

    Routing of packets. Bridging occurs at the Data Link Layer and regeneration of the digital

    signal happens at the Physical Layer. Gateway services act on all layers.

     6

Which three pairs of the following are Presentation layer standards?

    MPEG, MIDI, PICT,TIFF, JPEG,ASCII, and EBCDIC.

Which layer is responsible for putting 1s and 0s into a logical group?

    Layer 2 Data Link. Is responsible for transmission of data over a particular physical link.

Which layer is responsible for framing?

    Layer 2 Data Link. Responsible for transmission of data over a particular physical link.

Which layer is responsible for addressing devices and routing through an internetwork?

    Layer 3 Network. Provides connectivity and path selection between two end systems. The

    routing layer.

Which layer is responsible for flow control, acknowledgment, and windowing?

    Layer 4 Transport. Specifies reliable communication between end nodes. Establishes

    maintenance and termination of virtual circuits, transport fault detection, recovery and flow

    control.

    Which layer hides details of any network-dependent information from the higher layers by providing transparent data transfer?

    Layer 4 Transport. Specifies reliable communication between end nodes. Establishes

    maintenance and termination of virtual circuits, transport fault detection, recovery and flow

    control.

Which layer is responsible for coordinating communication between systems?

    Layer 5 Session. Establishes and terminates sessions between applications and manages

    the data exchange.

Which layer is responsible for negotiating data transfer syntax?

    Layer 6 - Presentation. This layer insures that the application layer of another system will

    understand what is being sent.

1. Which layer is responsible for synchronizing sending and receiving applications?

    2. Which layer is responsible for identifying and establishing the availability of the intended

    communication partner?

    3. Which layer is responsible for determining if sufficient resources for the intended communication

    exists?

    Layer 7 Application. E-mail, file transfer, and terminal emulation outside of the OSI model.

    Identifies and establishes the availability of intended communication partners and

    synchronizes the applications.

CPE is an acronym for which of the following?

    Customer Premises Equipment. Terminating and telephone equipment on a local site.

Which three of the following are true statements about connection-oriented sessions?

    Connection-oriented sessions take place at Transport Layer. TCP is responsible for segment

    delivery. Unacknowledged segments are resent. All received data is acknowledged by the

    sender. Segments are sequenced and put back into order upon arrival.

CSU/DSU is an acronym for which of the following?

    Channel Service Unit is a device that connects end-user equipment to the local digital

    telephone loop. Data Service Unit is used to adapt the physical interface on a DTE device to a

    circuit like T1. DSU does the signal timing as well.

     7

CO is an acronym for which of the following?

    Central office. The local telephone company office where local loops are connected to circuits.

Choose three reasons why the networking industry uses a layered model.

    It allows changes in one layer to occur without interrupting the operations of another layer.

    Allows for systematic troubleshooting.

Chapter 2

    Routers do not handle as much traffic as switches because routers take longer to process frames and packets because there is more to look at.

    Three kinds of switching

    ; Port switching allows a port to be assigned to a specific network segment.

    ; Frame Switching is used to increase bandwidth by allowing transmissions to occur in parallel.

    ; Cell Switching is used in ATM environments were cells are switched.

    Three switching modes

    ; Store and forward LAN switch copies the entire frame into buffers, and runs a CRC. High

    latency.

    ; Cut-Through LAN switch only copies the destination address and immediately forwards out

    the correct interface. All errors are filtered. Lowest latency.

    ; Fragment Free Modification of cut-through where the switch waits for the collision window to

    pass before forwarding. Checks only for collisions.

    Frame identification (tagging) uniquely assigns a user-defined ID to each frame‟s header field as it

    passes through the switch fabric. After passing the fabric, it removes the header for transmittal to the target host. It then removes the VLAN ID since nothing outside the switch would understand it. (Inter-Switch Link ISL is the only exception and keeps the VLAN ID as it passes over the ISL link.) All Layer 2 functions.

The CSMA/CD Ethernet IEEE committee is defined as which of the following?

    IEEE 802.3 uses CSMA/CD to access a network at a variety of speeds over different media.

    Other physical variations include

    10BaseT Cat 3 5 cable with one pair for sending, other pair for receiving @ 100 meters

    10Base2 Thin coaxial cable @ 185 meters

    10Base5 Thick coaxial cable @ 500 meters

The maximum distance of a 10Base5 network is which of the following?

    500 meters per segment.

Which of the following is a characteristic of a switch, but not of a repeater?

    Switches are network devices that filter, and forwards frames based on MAC address. Will

    send broadcast to all connected ports though.

How does the cut-through switching technique work?

    Packet switching where data is exiting the switch at the same time it is still entering the

    inbound port.

How do switches use store and forward?

    This is a packet-switching technique in which frames are completely processed before being

    forwarded out the port. The process includes calculating the CRC and checking the

    destination address. Frames are stored until network resources are available.

     8

Choose all of the following that are needed to support full-duplex Ethernet.

    Full duplex NICs

    Loopback and collision detection disabled.

What two types of technology does 100BaseT use?

    CSMA/CD and 802.3u. 100-Mbps baseband Fast Ethernet using UTP. Sends pulse signals

    over the network segment when no traffic is present.

Choose all of the following that are advantages to segmenting with routers.

    Manageability, Flow Control, Explicit packet lifetime control, and Multiple active paths.

Some advantages to segmenting with Bridges are?

    Manageability, reliability, and scalability. Bridges do not do datagram packet filtering.

Which two of the following describe frame tagging?

    Unique ID placed in header of each frame as it travels the switch fabric.

    A user-assigned ID defined to each frame.

    Used in VLANs to uniquely identify each frame.

Which of the following describes a full-duplex transmission?

    Uses a point to point connection from the transmitter of the transmitting station to the receiver

    of the receive station. Simultaneous data transmission between a sending and receiving

    station.

    If a frame is received at a switch and only the destination hardware address is read before the frame is forwarded, what type of switching method are you using?

    Cut-Through Switching. The device reads, processes, and forwards packets as soon as the

    destination address is looked up and the outgoing port determined. On-the-fly.

Which is true regarding store-and-forward switching method?

    Latency depends on frame length. Once received, the process calculates the CRC, checks

    the destination address, and temporarily stores the message. This has a higher latency period

    due to lag time in the router.

Which of the following switching types is the default for Cisco 5505s?

    Store and forward.

What is the IEEE specification for Spanning Tree?

    802.1d. STP is a bridge protocol that uses spanning-tree on a learning bridge to dynamically

    work around loops in a network topology by creating a spanning tree. Bridges exchange

    BPDU messages with other bridges to detect loops, and then shutdown interfaces that are

    looping.

What does the Spanning-Tree Algorithm (STA) do?

    STA is implemented by STP to prevent loops. Used by Spanning-Tree protocol to create a

    spanning tree.

Which can be true regarding VLANs?

    They are created by location, function, group, and department. Virtual LANs are a group of

    devices on one or more LANs that are configured so they communicate as if they were

    attached to the same wire when they are actually located on different segments. VLANs are

    based on logical grouping instead of physical and are very flexible.

     9

Of the three switching types, which one has the lowest latency?

    Cut-Through.

Of the three switching types, which one has the highest latency?

    Store and Forward.

Chapter 3

DOD Model

    Process/Application Layer (OSI Application, Presentation, Session) defines protocols for node-to-node application communication and controls user interface specs.

    Host-to-Host (OSI Transport Layer) defines protocols for setup of transmission service for applications. Creates reliable end-to-end communication and ensures the error-free delivery of data.

    Covers packet sequencing and data integrity.

    Internet (OSI Network Layer) gives hosts IP addresses, handles routing of packets, and communication flow between hosts.

    Network Access (OSI Data Link and Physical Layers) oversees hardware addressing and defines protocols for the physical transmission

UDP does not create a virtual circuit, and does not contact the destination before delivering info. But

    it also does not trust the lower layers and runs its own CRC. When IP sends a datagram, it has been informed from the upper layer of the IP address. However, IP

    must also inform a Network Access protocol like Ethernet or Token Ring of the destination hardware

    address. This is where ARP finds the hardware address for Ethernet. DSAP Destination Service Access Point - The SAP of the network node designated in the destination field of a packet.

    SSAP Source Service Access Point The SAP of the network node designated in the source field of a packet.

Which frame type use DSAPs and SSAPs to identify the upper-layer protocol?

    802.2 802.2 frames are really 802.3 frames with Logical Link Control header information.

What is the port number for TCP? UDP?

    TCP 6 and UDP 17. Network layer uses port 6h for TCP and port 17h for UDP.

Which of the following protocols are used to get an IP address from a known MAC address?

    RARP Reverse Address Resolution Protocol.

What does the acronym ARP stand for?

    Which protocol gets a hardware address from a known IP address?

    Address Resolution Protocol. Used to map IP addresses to MACs.

Which protocol works at the Internet layer and is responsible for making routing decisions?

    IP. It looks at the destination network address in the packet, forwards it based on the routing

    tables, and determines the best route to the destination.

Which port numbers are used by TCP and UDP to set up sessions with other hosts?

     10

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