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136 Cards in this Set
- Front
- Back
What are some characteristics of Transmission Control Protocol (TCP)?
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-Reliable
-Guaranteed Delivery -Connection-Oriented -Windowing +Error DETECTION via -Sequence number -ACK number |
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What are some characteristics of User Datagram Protocol (UDP) ?
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- Best Effort delivery
- No Error Detection - No Windowing - Connectionless |
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What are 3 things that TCP and UDP headers have in common?
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-Source Ports
-Destination Ports -Checksum |
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Why would someone choose to use UDP over TCP?
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Less Overhead. Header is smaller on UDP than TCP. Header is attached to each segment being transferred.
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What is the purpose of Flow Control and what are the 3 types?
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...provide a means for the receiver to govern the amount of data sent by the sender.
1)Buffering 2)Windowing 3)Congestion Avoidance |
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What 2 characteristics are most critical when implementing streaming video services?
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1) Bandwidth
2) Latency |
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What protocol is used to provide information about network problems?
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ICMP
Encapsulated within IP DATAGRAMS 2 common uses of ICMP are 1)Ping 2)Traceroute |
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What is ARP used for?
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ARP (Address Resolution Protocol) is used to resolve an IP address (Layer 3) to a MAC address (Layer 2)
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What is the purpose of DNS?
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The TCP/IP stack must find an IP Address for packets destined for a URL
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What is the purpose of DHCP?
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...a network device will automatically assign IP addresses to workstations.
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What is the command to properly configure Telnet access for 3 VTY lines and encrypt both the Enable and TELNET passwords?
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enable password xxx
service password-encryption line vty 0 2 password xxx login |
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What type of encryption is used with WPA2 ?
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AES
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What layer of the OSI model are SEGMENTS found at?
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TRANSPORT LAYER
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What layer of the OSI model are PACKETS found at?
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NETWORK LAYER
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What layer of the OSI model are FRAMES found at?
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DATA LINK LAYER
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What troubleshooting command will display PC network configuration?
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ipconfig /all
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What troubleshooting command will display the list of routers on a path to the destination?
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tracert
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What troubleshooting command will test VTY configuration?
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telnet
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What troubleshooting command will test TCP/IP protocol stack?
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ping 127.0.0.1
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What troubleshooting command will displays IP to MAC address mappings?
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arp -a
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If you cannot reach any sites on the Internet, but other users can, what should you check?
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You should check to make sure you can reach your DNS server.
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True or False
Switches allow simultaneous frame transmissions? |
True
Switches allow simultaneous frame transmissions |
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What can switches filter frames on?
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MAC Addresses when using port security
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What can you do to prevent unauthorized hosts from using the LAN?
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Use PORT SECURITY
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What happens if a SWITCH receives a MAC address that is not on its MAC address table?
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The frame goes out all ports EXCEPT the one it came in on.
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What do switches build and maintain that aid in routing?
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a MAC address table
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What is Store and Forward?
And what are its pros and cons? |
A switching method that copies and analyzes (runs Frame check seq) before forwarding the frame on..
This method takes longer (+latency) Error Free (filters ALL frame errors) |
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What is Cut-Through?
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Switching method that checks the destination address
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What is Fragment-free?
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Switching method that copies 1st 64 bytes
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What does Spanning Tree protocol do?
802.1D |
Prevents frames from duplicating and looping continuously through network by blocking redundant paths
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What are 3 things that can cause wireless performance issues?
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1) Metal file cabinets
2)Cordless phones 3) antenna type/direction |
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Some facts about WEP
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Wired Equivalence Privacy
Considered Weak Static Uses Pre-Shared Key |
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Some facts about WPA
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Wi-Fi Protected Access
Uses Pre-Shared Key (PSK) and Temporal Key Integrity Protocol (TKIP) Dynamic Encryption Keys Keys Change Automatically |
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Some facts about WPA2
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Wi-Fi Protected Access #2
uses AES/CCMP Stronger than WEP and WPA |
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When you see the Wi-Fi Logo on an Access Point or Client Adaptor it means what?
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1)The Wi-Fi Alliance has tested the device and determined that it meets IEEE WLAN std's
2) the device can inter-operate with other devices using the same standard. |
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What is the recommended percentage of overlap of signals from AP's in ESS?
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15%-20%
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Name 3 of the BEST PRACTICES for securing a network.
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1) Comprehensive Security Plan defining how to PHYSICALLY secure network equipment
2) Use of FIREWALL to restrict access from the outside -> in 3) Use SSH or other ENCRYPTED and AUTHENTICATED transport to access device config's. |
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What does the USER EXEC prompt look like and what is it used for?
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-Router>
-Used for monitoring router with "show" commands |
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What does the PRIVILEDGED EXEC prompt look like and what is it used for?
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-Router#
-Gives full access to all commands |
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What does the GLOBAL CONFIG prompt look like and what is it used for?
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-Router(config)#
-Used to configure the router globally - i.e. settings, name of router, etc.. |
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What does the INTERFACE CONFIGURATION prompt look like and what is it used for?
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-Router(config-if)#
-Commands that affect the interface - i.e. setting an IP address |
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What does the LINE CONFIGURATION prompt look like and what is it used for?
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-Router(config-line)#
-Used for configuring the CONSOLE or VTY lines - i.e. configuring passwords for remote access. |
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What is RAM memory and what does it store?
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-Random Access Memory (RAM)
-Stores Running-Config Running-IOS ARP Table |
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What is FLASH memory and what does it store?
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-Stores IOS images
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What is NVRAM memory and what does it store?
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-Non-Volatile Random Access Memory (NVRAM)
-STARTUP-CONFIGURATION |
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What is ROM and what does it store?
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-READ ONLY MEMORY (ROM)
-Basic microcode -Power On Self Test (POST) -RxBoot *and* -ROM monitor (ROMMON) which is limited to OS for troubleshooting. |
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Where is the Configuration Register stored?
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-Configuration Register is stored in NVRAM
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What are 2 ways to control the boot process of a router?
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1) CONFIGURATION REGISTER
2) BOOT SYSTEM COMMANDS** **more common method |
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What is altered that determines how the router will boot up?
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The last HEXADECIMAL VALUE of the CONFIGURATION REGISTER is altered thereby determining how the router will boot up.
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What are some of the alternative boot cycles defined by the Configuration Register?
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- 0x2102 =>Default
- 0x2100 =>ROMMON - 0x2101 =>RxBoot - 0x2102 =>Normal Bootup process. - 0x2142 =>**PASSWORD RECOVERY!! This value tells router NOT TO LOAD startup config. |
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What information does the output from the command SHOW VERSION display?
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-running IOS VERSION
-running IOS LOCATION & FILENAME -total RAM on device -equipped INTERFACES -TOTAL FLASH -CONFIGURATION REGISTER value |
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Routing occurs at what layer of the TCP/IP model?
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INTERNET LAYER of TCP/IP model is responsible for ROUTING
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When dealing with SWITCHES; what does it mean when you see (notconnect) in a SHOW INTERFACE output?
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(notconnect) means that the PC's NIC port and the SWITCH's port are configured with DIFFERENT DUPLEX SETTINGS.
i.e. one is FULL DUPLEX and the other is HALF DUPLEX |
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Why would you use a DEFAULT ROUTE?
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When you need to forward traffic to a network that is not listed in the routing table.
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CDP is found at what layer of the OSI model?
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CDP is found at the DATA LINK LAYER of the OSI model
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What command do you use to find out if CLOCKING is stopped on an interface?
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SHOW CONTROLLERS
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What are the 4 parts to the DHCP process?
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-DHCPDISCOVER
-DHCPOFFER -DHCPREQUEST -DHCPACK |
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What is the point of Private Addressing?
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Private addressing:
1)a scheme to conserve public addresses 2)are addresses that cannot be routed through the public internet |
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What are the Private Addresses?
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Class A: 10.0.0.0 - 10.255.255.255
Class B: 172.16.0.0 - 172.31.255.255 Class C: 192.168.0.0-192.168.255.255 |
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What is the IP Subnet Zero rule?
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When IP Subnet Zero rule is ENABLED be sure to ADD +2 to the number of networks for both rows B NETWORKS and C NETWORKS.
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What is the purpose of Network Address Translation (NAT)?
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-Hide Internal Addresses
-Preserve Public Addresses |
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What layer(s) of the OSI model make up the APPLICATION Layer of the TCP/IP model ?
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1)Application
2)Presentation 3)Session |
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What Layer(s) of the OSI model make up the TRANSPORT layer of the TCP/IP model?
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Transport
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What layer(s) of the OSI model make up the INTERNET layer of the TCP/IP model?
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NETWORK
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What layer(s) of the OSI model make up the NETWORK ACCESS layer of the TCP/IP model?
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1) DATA LINK
2) PHYSICAL |
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What is the ADMIN. DISTANCE of a Connected device?
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ADMIN. DISTANCE = 0
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What is the ADMIN DISTANCE of STATIC
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ADMIN. DISTANCE = 1
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What is the ADMIN DISTANCE of BGP
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ADMIN. DISTANCE = 20
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What is the ADMIN DISTANCE of EIGRP
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ADMIN. DISTANCE = 90
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What is the ADMIN DISTANCE of IGRP
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ADMIN. DISTANCE = 100
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What is the ADMIN DISTANCE of OSPF
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ADMIN. DISTANCE = 110
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What is the ADMIN DISTANCE of IS-IS
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ADMIN. DISTANCE = 115
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What is the ADMIN DISTANCE of RIP
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ADMIN. DISTANCE = 120
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What is the ADMIN DISTANCE of EIGRP (ext)
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ADMIN. DISTANCE = 170
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What is the ADMIN DISTANCE of BGP?
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ADMIN. DISTANCE = 200
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What are 4 Loop Prevention measures?
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1)Split Horizon
2)Hold-Down Timer 3)Triggered Update 4)Poison Reverse |
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What is Split Horizon?
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Split Horizon-is a method of preventing routing loops in distance-vector routing protocols by prohibiting a router from advertising a route back onto the interface from which it was learned.
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What is a Hold-Down Timer?
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a hold-down keeps a router from receiving route until the network appears to be stable -- until either an interface stops changing state (flapping) or a better route is learned.
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What is a Triggered Update?
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Triggered updates are used to prevent loops by exchanging routing information whenever there is change
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What is Poison Reverse?
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[answer]
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What is Data Terminal Equipment (DTE)
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-e.g. Routers
-normally located at the company buying the FRAME RELAY service. |
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What is Data Communications Equipment (DCE)?
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-e.g. Frame Relay Switches
-normally in the ISP network -provides clocking |
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What is a Virtual Circuit?
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A Virtual Circuit defines a logical path between two Frame Relay DTE's
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What is a Permanent Virtual Circuit?
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A PVC is essentially a leased line accessible any time its needed.
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What is a Switched Virtual Circuit?
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A SVC is essentially a dial up connection
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What is a Local Management Interface? (LMI)
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is a signaling standard used between routers and frame relay switches. Communication takes place between a router and the first frame relay switch it's connected to. Information about keepalives, global addressing, IP Multicast and the status of virtual circuits is commonly exchanged using LMI.
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What are the 3 standards of LMI?
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1)Cisco
2)ANSI 3)Q933a *DTE & DCE MUST USE SAME LMI |
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What keep a Frame Relay "alive"
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LMI messages act as KEEPALIVES for a Frame Relay
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What is a DLCI?
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A DLCI is a Layer 2 Frame Relay address
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What are 2 types of WAN data link encapsulation types (esp serial) ?
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1) HDLC (Cisco Proprietary serial int)
2) PPP (open std, works with any vendor) |
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What encapsulation should be used on a WAN serial connection if equipment is from different vendors?
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PPP encapsulation
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What is required for a point-to-point link to work?
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Both ends of the link MUST BE SAME ENCAPSULATION.
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What are some PPP features that HDLC does NOT have?
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1) Authentication using PAP/CHAP
2) Compression 3) Callback 4) Error Detection 5) Multi-link 6) Multi-protocol encaps |
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What is the difference between PAP and CHAP?
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PAP = Cleartext
CHAP = Hash |
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What does LCP do?
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handles the configuration, maintenance and teardown of any PPP connection. (including PPP callback, PAP, CHAP authentication, PPP Multilink, and error detection/correction, are all negotiated and handled by LCP)
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What is it called when you have multiple private IP's mapped to a single registered public IP using different ports?
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NAT Overload
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How do you get multiple internal hosts to use one IP address to access external resources?
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NAT Overload
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When do you implement a Default Route?
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A default route is used when a packet is destined for a remote network that is not listed in the routing table.
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List 3 facts and 1 example of Distance Vector.
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Facts:
1) Simple 2) Doesn't see entire topology; requires mechanisms to prevent loops. 3) Sends periodic broadcasts of routing table. Example: -RIP |
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List 3 facts and 2 examples of Link State.
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Facts:
1) Hierarchical 2) Sees entire topology 3) Uses "hello" messages to determine neighbors and only sends out changes about specific routes when there is a change. Example: - OSPF - IS-IS |
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what are the 6 metrics of EIGRP?
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-Hops
-Load -Bandwidth -Reliability -Delay -MTU |
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Which is faster Distance Vector or Link State?
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Link state protocols converge faster than distance vector protocols because routes can be flooded to
neighbors without having to run the routing algorithm |
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What is RIPv1 max hop count?
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15 max hop count, 16 is unreachable.
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How often do RIPv1 routers broadcast their entire routing table?
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Routers broadcast their entire table to the link-local broadcast address of 255.255.255.255 every 30
seconds |
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How do RIPv1 routers gather routes from its neighbors?
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Upon initialization, RIP routers issue requests for routes from neighbors
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What does RIPv2 have that RIPv1 doesn't?
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RIPv2 (defined in RFC 1723) expands on its predecessor to support:
Classless routing Authentication Next hop addresses External route tags Multicast advertisements (to 224.0.0.9) instead of broadcasts |
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Can RIPv2 communicate to RIPv1?
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RIPv2 can be run in compatibility mode, broadcasting advertisements to ensure backward compatibility
with RIPv1. |
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What are the different EIGRP packet types?
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Hello - Peer discovery and maintenance
Acknowledgment - Empty hello packets used to acknowledge messages Update - Convey route information Query - Request for a route Reply - Answer to a query |
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What does EIGRP consider by default?
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EIGRP can consider bandwidth, delay, reliability, and load in calculating a metric;
only bandwidth and delay are considered by default. |
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What kind of authentication does EIGRP support?
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EIGRP only supports MD5 authentication,
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What is PORT ADDRESS TRANSLATION (PAT)?
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Port Address Translation (PAT), or NAT overloading, maps multiple internal hosts to a single outside
address using layer 4 port numbers. |
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What are the 4 steps of a routers start up process?
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1. Test Hardware (POST)
2. Load bootstrap program 3. Locate and load Cisco IOS 4. Locate and Load the router configuration file |
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Where is the POST stored?
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ROM
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What are the 2 ways to revert back to the startup-config?
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1) Reboot the router manually
2) Restart the router with the "reload" command. |
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What are 5 ways to test a connection?
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-Telnet
-Ping -Trace -Show ip route -Show interfaces |
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Name the 4 ways a router can be accessed for configuration.
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- Console (CON)
- Auxiliary (AUX) - Virtual Terminals (VTY) - TFTP Server |
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What are the 5 passwords you can set in the Cisco IOS?
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- Enable Password
- Enable Secret - Console - AUX - VTY |
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What is the encrypted algorithm of "enable secret"?
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MD5
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Describe ROM
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- Loads bootstrap program that initializes the router's basic hardware components.
contains: Basic Microcode Power on Self Test (POST) RxBoot and ROM monitor aka (ROMMON) -limited OS to use for troubleshooting |
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What is the purpose for FLASH Memory?
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- Flash contains STORED IOS images.
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What does NVRAM do?
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- Stores Startup-Config
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Describe RAM
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- Contains the Running configuration
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What does ESS stand for and what does it allow for when implemented?
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Extended Service Set
- Allows roaming due to multiple access points |
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BSS within Wireless
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- Basic Service Set
- Single AP available |
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WEP
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RC4
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What are the 4 layers of TCP/IP
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1 - Network Interface
2 - Internetwork 3 - Transport 4 - Application |
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what are the 3 layers of the Cisco Three-Layer Hierarchical Model?
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Access Layer
Distribution Layer Core Layer |
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What 4 things can an EXTENDED ACL filter on?
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1. Source IP Address
2. Destination IP Address 3. TCP or UDP port number 4. Protocol |
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What do standard ACL's filter on?
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-SOURCE IP ADDRESS
-Entire Protocol Suite |
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Where should a standard ACL be placed?
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Closest to the destination
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Where should an extended ACL be placed
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As close to the source as possible
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What is used when the router is unable to match a destination network with an entry in its routing table?
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Default Route
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What is a manually configured route called?
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Static Route
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What address never changes no matter how many hops a packet takes?
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Source and Destination IP Address
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What address changes at each hop or router?
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MAC Address
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What is the function of a router?
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To determine the best path from a source to a destination
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