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69 Cards in this Set
- Front
- Back
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Describe the process of routing packets.
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Routing is the act of moving information across an internetwork from a source to a destination.
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What are some routing algorithm types?
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Static, dynamic, flat, hierarchical, host-intelligent, router-intelligent, intradomain, interdomain, link-state, and distance vector.
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Describe the difference between static and dynamic routing.
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Static routing is configured by the network administrator and is not capable of adjusting to changes in the network without network administrator intervention. Dynamic routing adjusts to changing network circumstances by analyzing incoming routing update messages without administrator intervention.
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What are some of the metrics used by routing protocols?
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Path length, reliability, delay, bandwidth, load, and communication cost.
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What are the design goals of routing algorithms?
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Optimality
Simplicity and low overhead Robustness and stability Rapid convergence Flexibility |
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What are the two types of routing algorithms and give examples of each?
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Distance Vector: RIP, RIPv2, and IGRP
Link State: OSPF |
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Why do routers use network-layer addresses as the basis for routing?
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To ease the tasks of sorting and recall because network addresses are hierarchial.
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What is the dotted decimal system?
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decimal number, between 0:255, seperated by dots (periods).
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Which organization isssues IP addresses?
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Network Information Center or NIC.
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What is the IP address of the "default network"?
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0.0.0.0
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What is the IP address of the "Internal Loopback Network"?
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127.0.0.0
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What is an IP address with all host bits set to 0?
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It is the "Network Address".
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What is an IP address with all host bits set to 1?
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Broadcast address
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Which networks are reserved for private use and cannot be used on the Internet?
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10.x.x.x
172.16.x.x to 172.31.x.x 192.168.x.x |
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Define subnetting.
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Procedure for dividing Class A, B, and C networks into smaller, more manageable sections. Uses a three-level hierarchy that divides the host portion of an IP address into two sections: a subnet number and the remaining host portion.
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What is "classful addressing"?
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IP addresses are divided into categories called classes. Each IP class is designed to accommodate different size networks.
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why is the command "ip subnet-zero" used?
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To enable the use of subnet zero for interface addresses.
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What is the "extended network prefix"?
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the combination of network and subnet portions of the ip address.
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Why shouldn't subnets, with all bits equal to 0, be used?
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Some routing protocols do not transmit subnet masks with route updates, so classful is assumed.
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Name two protocols that do not include subnet masks in routine updates.
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Routing Information Protocol version 1 (RIPv1) and
Interior Gateway Routing Protocol (IGRP). |
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Which five protocols support variable length subnet masks (VLSM)?
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Open Shortest Path First (OSPF)
Enhanced Interior Gateway Routing Protocol (EIGRP) Routing Information Protocol version 2 (RIPv2) Integrated Intermediate System to Intermediate System (Integrate IS-IS). Static Routing |
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What is route aggregation?
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The process of combining multiple subnets into a single routing update.
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What characteric must be present to effectively utilize route aggregation?
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IP addressing scheme must be topologically significant (subnets must be assigned contiguously to each other).
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Which IOS configuration command is used to enable IP Supernetting?
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config# ip classless
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What is a discontiguous network?
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a network which has been subnetted but the two subnets are not physically accessable to each other via a router because of the use of a different network address.
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Name 2 protocols that don't handle discontiguous networks well.
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RIPv1
IGRP |
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Define CIDR.
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Classless InterDomain Routing. Technique based on route aggregation. CIDR allows routers to group routes together in order to cut down on the quantity of routing information carried by the core routers.
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Which protocols support CIDR's need to exchange prefix info?
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Border Gateway Protocol version 4, (BGP)
EIGRP, OSPF, IS-IS |
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Which protocols are part of the IP Protocol Suite?
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Address Resolution Protocol (ARP)
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What 2 pieces of infomation does an ARP table entry associate?
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MAC address and IP address.
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What is a proxy arp?
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Variation of the ARP protocol in which an intermediate device (i.e., a router) sends an ARP response on behalf of an end node to the requesting host. Proxy ARP can lessen bandwidth use on slow-speed WAN links.
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What is spoofing?
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when one machine pretends to be another machine in order to intercept packets.
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What is ICMP?
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Internet Control Message Protocol. Used in ping. ICMP messages are either error messages or queries and responses used to manage communication on internetworks.
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What is a "gateway of last resort"?
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A destination network that a router should send packets to if it doesn't have a specific entry to the destination entry to the destination network in its routing table. The gateway address can either be configured directly on the router or it can be learned from another network.
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What is a "default route"?
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Routing table entry that is used to direct frames for which a next hop is not explicitly listed in the routing table.
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How does configure a gateway of last resort?
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config# ip default-network <ip address>
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What is a static route?
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it is a route that you manually configure into a routing table. With a static route you can specify that packets destined for a specific network, subnet, or host should be forwarded to a desired network or interface. You can also assign administrative distances to static routes.
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How is a static route configured?
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config# ip route <ip route prefix> <mask> <ip address>
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How do I display the ip routing table?
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router# show ip route
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How do I display only those routing table entries that were learned via a specific protocol?
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router# show ip route <protocol>
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How do I display the route table entries for a specific network address?
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router# show ip route <ip address>
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How do I display the number of networks and subnets that have been learned and the amount of memory used to store each?
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router# show ip route summary
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How do I clear one or all entries from the routing table?
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router# clear ip route <* or ip address>
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How do I display, by protocol, the parameters that are being used to send and receive updates, the metrics it is using, and the networks it is advertising.
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router# show ip protocols
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How do I display the ARP Table?
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router# show ip arp
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How do I clear the ARP Table?
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router# clear arp-cache
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How do I display a secondary ip address, if it exists, for an interface?
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router# show ip interface
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How do I display statistics for all interfaces?
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router# show interfaces
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How do I display just the ip addresses assigned on each interface and the status of each interface?
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router# show ip interface brief
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Name 2 diagnostic commands?
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Ping and Traceroute.
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For what does ping stand?
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Packet INternet Groper
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What does ping do?
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Sends ICMP echo messages. When received by destination, it sends an echo response.
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How do I enter extended ping commands?
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on the command line, enter only ping, causing user prompts for arguments. Answer yes (y) to question "Extended commands?"
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Why use traceroute vs. ping with record option?
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Ping can only record up to 9 hops where traceroute is unlimited.
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From what protocol are the traceroute probe packets?
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UDP: User Datagram Protocol
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What are the 2 error messages traceroute probe packets generate and at which routers are they seen?
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"Time exceeded", seen at 1st and all routers except the last destination node which will then give the error message "ICMP port unreachable".
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How do I display the number of packets received, generated or forwarded?
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router# debug ip packet
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What packet types are not recorded by traceroute?
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Fast-Switched Packets.
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How do I disable fast switching of packets?
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config-if# no ip route-cache
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How do I display routing transaction information for a particular protocol?
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router# debug ip <protocol>
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How do I display routing table updates and route-cache updates?
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route# debug ip routing
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How do I display ICMP transaction information?
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router# debug ip icmp
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Name 5 Classless routing protocols
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RIPv2
EIGRP OSPF IS-IS BGP |
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Name 2 Classful routing protocols
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RIPv1
IGRP |
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What does IGP and EGP stand for?
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Interior Gateway Protocol
Exterior Gateway Protocol |
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What is the only viable EGP?
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Border Gateway Protocol (BGP)
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Name 5 IGPs
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RIP, IGRP, EIGRP, OSPF, IS-IS
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How do I display RIP route information?
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config# show ip rip database
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How can Administrative Distance be displayed for a static route or directly connected device?
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router# show ip route <ip route>
this form of the show ip route command show more detail when the ip route option is given. |
