Chapter 6 Cisco Netacad
What are the recommended steps that should be completed when configuring the initial setting on a router?
1) assign a device name 2) set passwords A) secure privileged EXEC mode B) secure the console port C) secure the virtual access (VTY for Telnet) D) set the service password-encryption 3) set the banner MOTD 4) save the configuration 5) verify the configuration using the show run command
List and explain the basic characteristics of IP
A) Connectionless- no connection with the destination is established before sending data packets B) Best effort- (unreliable) packet delivery is not guaranteed C) Media independent- operation is independent of the medium carrying the data.
The IPv6 simplified header offers several advantages over IPv4. These include:
A) Better routing efficiency for performance and forwarding-rate scalability B) no requirements for processing checksums (thus networking performance improvement) C) simplified and more efficient extension header mechanisms D) a flow label field for per-flow processing with no need to open the transport inner packet to identify various traffic flows (performance improvement)
Similar to a Cisco switch, there are several ways to access the CLI environment on a Cisco router. List and explain the most common methods.
A) Console- uses a low speed serial or USB connection to provide a direct connect, out-of-band management access to a Cisco device. B) Telnet or SSH- two methods for remotely accessing a CLI session across an active network interface. C) AUX port- used for remote management of the router using a dial-up telephone line and modem.
the routing table of a local host typically contains what information?
A) Direct connection (networks directly attached) B) Local network route (Local networks that get me to remote network) C) Local default route (Route to take when i cannot find a pathway)
list and explain what the routing table of a router stores information about
A) Directly connected routes- These routes come from the active router interfaces. Routers add a directly connected route when an interface is configured with an IP address and is activated. Each of the routers interfaces is connected to a different network segment. Routers maintain information about the network segments that they are connected to within the routing table. B) Remote routes- these routes come from remote networks connected to other routers. Routes to these networks can either be manually configured on the local router by the network administrator or dynamically configured by enabling the local router to exchange routing information with other routers using dynamic routing protocols. The dynamic process learns remote routes thru the Remote Router Advertisements of their Routes.
which two files are loaded when a router is booted?
A) IOS image file B) startup configuration file
The output from the show version command includes:
A) IOS version B) ROM bootstrap program C) location of IOS D) CPU and amount of RAM E) interfaces F) amount of NVRAM and flash G) config register setting - Default 0x2102
List and explain three major issues IPv4 has
A) IP address depletion- IPv4 has a limited number of unique public IP addresses, the increasing number of new IP-enabled devices, always-on connection, and the potential growth of less-developed regions have increased the need for more addresses B) internet routing table expansion- A routing table is used by routers to make best path determinations. As the number of servers (nodes) connected to the internet increases, so too does the number of network routes. These IPv4 routes consume a great deal of memory and processor resources on Internet routers C) Lack of end-to-end connectivity- Network Address Translation (NAT) is a technology commonly implemented within IPv4 networks. NAT provides a way for multiple devices to share a single public IP address. However, because the public IP address is shared, the IP address of an internal network host is hidden. This can be problematic for technologies that require end-to-end connectivity
What steps are required to activate a router interface?
A) IPv4 address and subnet mask B) activate the interface
List 4 improvements that IPv6 provides
A) Increased address space B) improved packet structure C) eliminates the need for checksums D) integrated security
the fields used to identify and validate a packet, or reorder a fragmented packet include:
A) Internet Header Length (IHL) B) Total length C) Header checksum
the fields in the IPv6 header include:
A) Version B) Traffic Class C) Flow Label D) Payload length E) Next header F) Hope limit G) Source address H) Destination address
Router interfaces can be grouped into two categories. list and explain both.
A) ethernet LAN interfaces- used for connection cables that terminate with LAN devices, such as computers and switches. This interface can also be used to connect routers to each other. Several conventions for naming ethernet interfaces are popular: the older Ethernet, FastEthernet, and Gigabit ethernet. The name used depends on the device type and model. B) Serial WAN interfaces- used for connecting routers to external networks, usually over a larger geographical distance. Similar to LAN interfaces, each serial WAN interface has its own IP address and subnet mask, which identifies it as a member of a specific network.
The connections on a Cisco router can be grouped into two categories. list and explain each.
A) management ports- these are the console and auxiliary ports used to configure, manage, and troubleshoot the router. unlike LAN and WAN interfaces, management ports are not used for packet forwarding. B) inband router interfaces- these are the LAN and WAN interfaces configured with IP addressing to carry user traffic. ethernet interfaces are the most common LAN connections, while common WAN connections include serial and DSL interfaces.
all router models are essentially computers. just like computers, tablets, and smart devices, routers also require:
A) operating system (OS) B) Central processing units (CPU) C) Random-access memory (RAM) D) Read-only memory (ROM)
list the four steps to the router boot process in correct order
A) perform POST B) load bootstrap C) load the IOS D) load the configuration file from flash
there are three major phases to the bootup process. These are:
A) perform the POST and load the bootstrap program B) locate and load the CISCO IOS software C) locate and load the startup configuration file or enter startup mode
what commands on a Windows host can be used to display the host routing table?
A) route print B) netstat -r
What are the other commands that can be used to verify interface configuration?
A) show ip route B) show interfaces C) show ip interface
Explain what each letter in a routing table represents
C- identifies a directly connected network. Directly connected networks are automatically created when an interface is configured with an IP address and activated. L- identifies that this is a link local route. link local routes are automatically created when an interface is configured with an IP address and is activated. S- identifies that the route was manually created by an administrator to reach a specific network. This is known as a static route. D- identifies that the route was learned dynamically from another router using Enhanced Interior Gateway Routing Protocol (EIGRP) O- identifies that the route was learned dynamically from another router using the Open Shortest Path First (OSPF) routing protocol.
Where is the Cisco IOS stored?
Flash memory
During the bootup, the Cisco IOS is copied into?
RAM
a router has access to four types of memory. explain each.
RAM- ram is used to store various applications and processes including: -Cisco IOS: the IOS is copied into RAM during bootup -Running config file: this is the configuration file that stores the configuration commands that the router IOS is currently using. It is also known as the running-config. -IP routing table: this file stores information about directly-connected and remote networks. It is used to determine the best path to use to forward packets. -ARP cache: this cache contains the IPv4 address to MAC address mappings, similar to the ARP cache on a PC. The ARP cache is used on routers that have LAN interfaces, such as Ethernet interfaces. -Packet buffer: packets are temporarily stored in a buffer when received on an interface or before they exit an interface. Like computers, Cisco routers actually use dynamic random-access memory (DRAM) -DRAM: it stores the instructions and data needed to be executed by the CPU ROM- cisco routers use ROM to store: -Bootup instructions: provides the startup instructions. -Basic diagnostic software: performs the power-on self-test (POST) of all components. -Limited IOS: Provides a limited backup version of the OS, in case the router cannot load the full featured IOS. NVRAM- is used by the Cisco IOS as permanent storage for the startup configuration file Flash memory- is non-volatile computer memory used as permanent storage for the IOS and other system related files.
What is the command used to configure the default gateway 10.250.1.1 on a switch?
S1(config)# ip default-gateway 10.250.1.1
a common misconception is that the switch uses its configured default gateway address to determine where to forward packets originating from hosts connected to the switch and destined for hosts on a remote network. What does the switch use its default gateway for?
The IP address and default gateway information is only used for packets that originate from the switch. Packets originating from hosts connected to the switch must already have default gateway information configured to communicate on remote networks.
the factory default setting for the configuration register is 0x2102. What does this value mean?
This value indicates that the router attempts to load a cisco IOS software imagine from flash memory and load the startup configuration file from NVRAM
What is fragmenting the packet or fragmentation?
When an intermediate device, usually a router, must split up a packet when forwarding it from one medium to a medium with a smaller MTU.
Why would a router have to fragment a packet?
When forwarding it from one medium to another medium that has a smaller MTU
What does a local host require to send packets to a remote destination?
a default gateway
explain what a routing table is. (Show ip route) Displays Route table
a routing table is a data file in RAM that is used to store route information about directly connected networks, as well as entries of remote networks the device has learned about
a router also has special memory that includes:
flash and nonvolatile random-access memory (NVRAM)
the default gateway is only used when a host must forward packets to a remote network. When is a default gateway not required, or needed to be configured?
if you are only sending packets to devices on the local network
The configuration register has several uses, such as:
password recovery
there are several commands that can be used to verify interface configuration. Which is the most useful of these commands?
show ip interface brief
What command is used on a Cisco IOS router to display the routing table information?
show ip route
What command can be used to verify and troubleshoot some of the basic hardware and software components of the router?
show version
there is one major characteristic of the media that the network layer considers. This is:
the maximum size of the PDU that each medium can transport
If a router receives a packet to a destination network that is not in the routing table and no default gateway is available, what happens to the packet?
the packet is dropped
Where is the default gateway generally located?
the router interface address attached to the local network of the host
What is the purpose of a default gateway?
to route traffic from the local network to devices on remote networks
for an end device to communicate over the network, it must be configured with the correct IP address information, including the default gateway address. When is the default gateway used?
when the host wants to send a packet to a device on another network
