ENetwork v4.0 Chapter 9

1) In the graphic, Host A has reached 50% completion in sending a 1 KB Ethernet frame to Host D when Host B wishes to transmit its own frame to Host C. What must Host B do?
ans:
Host B must wait until it is certain that Host A has completed sending its frame.
2) Ethernet operates at which layers of the OSI model? (Choose two.)
ans:
Physical layer
Data-link layer
3) Which of the following describe interframe spacing? (Choose two.)
ans:
the minimum interval, measured in bit-times, that any station must wait before sending another frame
the time allowed for slow stations to process a frame and prepare for the next frame
4) What three primary functions does data link layer encapsulation provide? (Choose three.)
ans:
addressing
error detection
frame delimiting
5) When a collision occurs in a network using CSMA/CD, how do hosts with data to transmit respond after the backoff period has expired?
ans:
The hosts return to a listen-before-transmit mode. <—
6) What are three functions of the upper data link sublayer in the OSI model? (Choose three.)
ans:
identifies the network layer protocol
makes the connection with the upper layers
insulates network layer protocols from changes in physical equipment
7) What does the IEEE 802.2 standard represent in Ethernet technologies?
ans:
Logical Link Control sublayer
Why do hosts on an Ethernet segment that experience a collision use a random delay before attempting to transmit a frame?
ans:
A random delay helps prevent the stations from experiencing another collision during the transmission.
9.Refer to the exhibit. Which option correctly identifies content that the frame data field may contain?
ans:
network layer packet
10) Host A has an IP address of 172.16.225.93 and a mask of 255.255.248.0. Host A needs to communicate with a new host whose IP is 172.16.231.78. Host A performs the ANDing operation on the destination address. What two things will occur? (Choose two.)
ans:
Host A will broadcast an ARP request for the MAC of the destination host.
A result of 172.16.225.255 will be obtained.
11) Which of the following is a drawback of the CSMA/CD access method?
ans:
Collisions can decrease network performance.
12) Ethernet operates at which layer of the TCP/IP network model?
ans:
network access
13) What is the primary purpose of ARP?
ans:
resolve IPv4 addresses to MAC addresses
14) Refer to the exhibit. The switch and workstation are administratively configured for full-duplex operation. Which statement accurately reflects the operation of this link?
ans:
No collisions will occur on this link.
15) Refer to the exhibit. Host_A is attempting to contact Server_B. Which statements correctly describe the addressing Host_A will generate in the process? (Choose two.)
ans:
A frame with the destination MAC address of Router_A.
A packet with the destination IP of Server_B.
16) Which statements correctly describe MAC addresses? (Choose three.)
ans:
copied into RAM during system startup
contains a 3 byte OUI
6 bytes long
17) Which two features make switches preferable to hubs in Ethernet-based networks? (Choose two.)
ans:
minimizing of collisions
increase in the throughput of communications
18) What are the two most commonly used media types in Ethernet networks today? (Choose two.)
ans:
copper UTP
optical fiber
19) Convert the binary number 10111010 into its hexadecimal equivalent. Select the correct answer from the list below.
ans:
BA
20) After an Ethernet collision, when the backoff algorithm is invoked, which device has priority to transmit data?
ans:
any device in the collision domain whose backoff timer expires first
21) Host A has an IP address of 172.16.225.93, a mask of 255.255.248.0, and a default gateway of 172.16.224.1. Host A needs to send a packet to a new host whose IP is 172.16.231.78. Host A performs the ANDing operation on its address and subnet mask. What two things will occur? (Choose two.)
ans:
Host A will broadcast an ARP request for the MAC of the host 172.16.231.78.
Host A will change the destination IP of the packet to 172.16.224.1 and forward the packet.

Configuring Cisco Catalyst Switch

Here I will explain about configuring a Cisco Catalyst Switch

• Preparation to Configure a Switch
• Basic Switch Configuration:
• Management Interface Considerations
• Configure Management Interface
• Configure Default Gateway
• Verify Configuration
• Configure Duplex and Speed
• Configure a Web Interface

Prepare to Configure the Switch
The initial startup of a Catalyst switch requires the completion of the following steps:
Step 1. Before starting the switch, verify the following:
All network cable connections are secure.
Your PC or terminal is connected to the console port. Your terminal emulator application, such as HyperTerminal is running and configured properly. The figure shows a PC connected to a switch using the console port.
The figure below shows the correct configuration of HyperTerminal, which can be used to view the console of a Cisco device. In here I'm using a USB-to-RS232 converter the driver make a new Serial Port COM 15. If your PC or Laptop already has a Serial Port it should be COM 1.



















Step 2. Attach the power cable plug to the switch power supply socket. The switch will start. Some Catalyst switches, including the Cisco Catalyst 2960 series, do not have power buttons.
Step 3. Observe the boot sequence as follows:
When the switch is on, the POST begins. During POST, the LEDs blink while a series of tests determine that the switch is functioning properly. When the POST has completed, the SYST LED rapidly blinks green. If the switch fails POST, the SYST LED turns amber. When a switch fails the POST test, it is necessary to repair the switch.
Observe the Cisco IOS software output text on the console.

The Boot Process on console should be like this:

Copyright (c) 1986-2006 by Cisco Systems, Inc,.

Compiled Fri 28-Jul-06 04:33 by yenanh

Image text-base: 0x0o003000, data—base: OxOOAA2F34

flashfs[l]: 602 files, 19 directories

flashfs[1]: 0 orphaned files, 0 orphaned directories flashfs[1r]: Tota1 bytes: 32514048

flashfs[1]: Bytes used: 7715328

flashfs[1]: Bytes available: 24798720

flashfs[1]: flashfs fsck took 1 seconds.

flashfs[1]: Initia1ization complete....done Initia1izing flashfs.

POST: CPU MIC register Tests : Begin

POST: CPU MIC register Tests : End, status Passed

POST: PortASIC Memory Tests : Begin

POST: PortASIC Memory Tests : End, Status Passed

POST: CPU MIC PostASIC interface Loopback Tests : Begin

POST: CPU MIC PostASIC interface Loopback Tests : End, Status Passed

POST: PostASIC RingLoopback Tests : Begin

POST: PostASIC RingLoopback Tests : End, Status Passed

POST: PostASIC CAM Subsystem Tests: Begin

During the initial startup of the switch, if POST failures are detected, they are reported to the console and the switch does not start. If POST completes successfully, and the switch has not been configured before, you are prompted to configure the switch.


Management Interface Considerations
An access layer switch is much like a PC in that you need to configure an IP address, a subnet mask, and a default gateway. To manage a switch remotely using TCP/IP, you need to assign the switch an IP address. In the figure, you want to manage S1 from PC1, a computer used for managing the network. To do this, you need to assign switch S1 an IP address. This IP address is assigned to a virtual interface called a virtual LAN (VLAN), and then it is necessary to ensure the VLAN is assigned to a specific port or ports on the switch.

The default configuration on the switch is to have the management of the switch controlled through VLAN 1. However, a best practice for basic switch configuration is to change the management VLAN to a VLAN other than VLAN 1. The implications and reasoning behind this action are explained in the next chapter. The figure illustrates the use of VLAN 99 as the management VLAN; however, it is important to consider that an interface other than VLAN 99 can be considered for the management interface.


Configure Management Interface
To configure an IP address and subnet mask on the management VLAN of the switch, you must be in VLAN interface configuration mode. Use the command interface vlan 99 and enter the ip address configuration command. You must use the no shutdown interface configuration command to make this Layer 3 interface operational. When you see "interface VLAN x", that refers to the Layer 3 interface associated with VLAN x. Only the management VLAN has an interface VLAN associated with it.

Note that a Layer 2 switch, such as the Cisco Catalyst 2960, only permits a single VLAN interface to be active at a time. This means that the Layer 3 interface, interface VLAN 99, is active, but the Layer 3 interface, interface VLAN 1, is not active.

Here is the Cisco IOS CLI Command Syntax:

S1#configure terminal
S1(config)#interface vlan 99
S1(config-if)#ip address 172.17.99.11 255.255.0.0
S1(config-if)#no shutdown
S1(config-if)#end
S1#configure terminal
S1(config)#interface fastethernet 0/18
S1(config-if)#switchport mode access
S1(config-if)#switchport acces vlan 99
S1(config-if)#end
S1#copy running-config startup-config

Configure Default Gateway
You need to configure the switch so that it can forward IP packets to distant networks. The default gateway is the mechanism for doing this. The switch forwards IP packets with destination IP addresses outside the local network to the default gateway. In the figure, router R1 is the next-hop router. Its IP address is 172.17.99.1.

To configure a default gateway for the switch, use the ip default-gateway command. Enter the IP address of the next-hop router interface that is directly connected to the switch where a default gateway is being configured. Make sure you save the configuration running on a switch or router. Use the copy running-config startup-config command to back up your configuration.


Verify Configuration
Here is an abbreviated screen output showing that VLAN 99 has been configured with an IP address and subnet mask, and Fast Ethernet port F0/18 has been assigned the VLAN 99 management interface:

S1#show running-config
...
!
interface FastEthernet0/18
switchport access vlan 99
switchport mode access
...
!
interface Vlan99
ip address 172.17.99.11 255.255.255.0
no-ip route cache
!

Show the IP Interfaces
Use the show ip interface brief to verify port operation and status. Y

The mdix auto Command

You used to be required to use certain cable types (cross-over, straight-through) when connecting between specific devices, switch-to-switch or switch-to-router. Instead, you can now use the mdix auto interface configuration command in the CLI to enable the automatic medium-dependent interface crossover (auto-MDIX) feature.

When the auto-MDIX feature is enabled, the switch detects the required cable type for copper Ethernet connections and configures the interfaces accordingly. Therefore, you can use either a crossover or a straight-through cable for connections to a copper 10/100/1000 port on the switch, regardless of the type of device on the other end of the connection.

The auto-MDIX feature is enabled by default on switches running Cisco IOS Release 12.2(18)SE or later. For releases between Cisco IOS Release 12.1(14)EA1 and 12.2(18)SE, the auto-MDIX feature is disabled by default.


Configure Duplex and Speed
You can use the duplex interface configuration command to specify the duplex mode of operation for switch ports. You can manually set the duplex mode and speed of switch ports to avoid inter-vendor issues with autonegotiation. Although there can be issues when you configure switch port duplex settings to auto, in this example, S1 and S2 switches have the same duplex settings and speeds. The figure describes the steps to configure the port F0/1 on the S1 switch.

Here is the Cisco IOS CLI Command Syntax:

S1#configure terminal

S1(config)#Interface fastethernet 0/1

S1(config-if)#duplex auto

S1(config-if)#speed auto

S1(config-if)#end

S1#copy running-config startup-config

Configure a Web Interface
Modern Cisco switches have a number of web-based configuration tools that require that the switch is configured as an HTTP server. These applications include the Cisco web browser user interface, Cisco Router and Security Device Manager (SDM), and IP Phone and Cisco IOS Telephony Service applications.

To control who can access the HTTP services on the switch, you can optionally configure authentication. Authentication methods can be complex. You may have so many people using the HTTP services that you require a separate server specifically to handle user authentication. AAA and TACACS authentication modes are examples that use this type of remote authentication method. AAA and TACACS are authentication protocols that can be used in networks to validate user credentials. You may need to have a less complex authentication method. The enable method requires users to use the server's enable password. The local authentication method requires the user to use the login username, password, and privilege level access combination specified in the local system configuration (by the username global configuration command).

Here is the Cisco IOS CLI Command Syntax:
S1#configure terminal
S1(config)#ip http authentication enable
S1(config)#ip http server
S1(config)#end

Cisco Certified Voice Professional (CCVP)

I see there are a lot of materials in my office now to learn about Voice-Over-IP solutions. In addition, my first task now is to help a team that develops Advanced Technology Demo Units Voice and Unified Communications plus Cisco IP Interoperability and Collaboration System (IPICS). Besides, one of my team just finished her Bachelor's Thesis about IP Telephony and Cisco Unified Communications Manager (CallManager), maybe she can explain or teach me something regarding to IP Telephony.
Then, my friend told me that maybe I should take CCVP rather than CCNP since the condition and environment of my office can support me in pursuing CCVP.
The CCVP (Cisco Certified Voice Professional) validates a network professional's ability to implement and operate Cisco Unified Communications solutions in single site and multi-site deployments. Individuals who hold a CCVP certification can help create an IP telephony solution that is transparent, scalable, and manageable. The CCVP curriculum focuses on Cisco Unified CallManager, voice gateways and gatekeepers, switches, Unified IP Phones, and skills to secure the voice communications and ensure voice quality of service. Candidates must pass five secure, proctored certification-quality exams to become a Cisco Certified Voice Professional (CCVP). The prerequisite for the Cisco Certified Voice Professional (CCVP) is CCNA. As voice technologies continue to grow in importance Cisco helps you keep pace with a rapidly changing world.

The CCVP provides network professionals with the knowledge, skills, and credentials necessary to design and implement end-to-end Cisco IP Telephony solutions. The certification content focuses on Cisco Call Manager, QoS, gateways, gatekeepers, IP phones, voice applications and utilities on Cisco routers and Catalyst switches..

Required Exam(s)	Recommended Training
642-642 QoS	Quality of Service (QoS)
642-432 CVOICE	Cisco Voice over IP (CVOICE) AND Cisco Voice over IP Fundamentals (CVF)
642-426 TUC	Troubleshooting Cisco Unified Communications Systems (TUC)
642-444 CIPT 4.1 OR 642-445 CIPT 5.0	Cisco IP Telephony Part 1 (CIPT1 4.1) AND Cisco IP Telephony Part 2 (CIPT2 4.1) OR Cisco IP Telephony Part 1 (CIPT1 5.0) AND Cisco IP Telephony Part 2 (CIPT2 5.0)
642-453 GWGK	Implementing Cisco Voice Gateways and Gatekeepers (GWGK)

So the steps that I should take are Cisco Voice Fundamentals, a 6-hour e-learning course to establish a strong foundation in VoIP and PSTN fundamentals, then CVOICE, followed by CIPT1, GWGK, or QoS in any order. CIPT2 should be completed only after completing CIPT1.

The final course in the series, IP Telephony Troubleshooting is best taken after having completed the other CCVP courses in the curriculum. Those will help me better understand how to install, configure and deploy the various voice products and technologies tested in the CCVP exams.

From the information that I got, there will be 5 exams to pass:

• CVOICE is the foundation for it all (the most useful exam)
• QoS is not much based on anything; but you need to have some background so it is better after CVOICE (the most interesting one)
• GWGK is CVOICE2 (the hardest to master)
• TUC has some parts built on CIPT knowledge (the easiest to do)
• CIPT is a lot better after GWGK (the most boring)

I will think about CCVP and CCNP, which one should I choose for now...

Cram Exam Notes 5 Cisco Certified Network Associate CCNA

51.Routing metrics used by IGRP:

Bandwidth, MTU, Reliability, Delay, and Load.

1. Bandwidth: This is represents the maximum throughput of a link.

2. MTU (Maximum Transmission Unit): This is the maximum message length that is acceptable to all links on the path. The larger MTU means faster transmission of packets.

3. Reliability: This is a measurement of reliability of a network link. It is assigned by the administrator or can be calculated by using protocol statistics.

4. Delay: This is affected by the band width and queuing delay.

5. Load: Load is based among many things, CPU usage, packets processed per sec.

52. The metric limit for link-state protocols is 65,533

53. Following are the possible solutions for preventing routing loops.

1. Split Horizon - based on the principle that it is not useful to send the information about a route back in the direction from which the information originally came.

2. Poison Reverse - A router that discovers an inaccessible route sets a table entry consistent state (infinite metric) while the network converges.

3. Hold-down Timers - Hold down timers prevent regular update messages from reinstating a route that has gone bad. Here, if a route fails, the router waits a certain amount of time before accepting any other routing information about that route.

4. Triggered Updates - Normally, new routing tables are sent to neighboring routers at regular intervals (IP RIP every 30 sec / and IPX RIP every 60 sec). A triggered update is an update sent immediately in response to some change in the routing table. Triggered updates along with Hold-down timers can be used effectively to counter routing loops.

54. IP RIP based networks send the complete routing table during update. The default update interval is 30 seconds. IGRP update packet is sent every 90 seconds by default.

55. For IGRP routing, you need to provide the AS (Autonomous System) number in the command. Routers need AS number to exchange routing information. Routers belonging to same AS exchange routing information. OSPF, and IGRP use AS numbers.

56. CDP stands for Cisco Discovery Protocol. This protocol is proprietary of Cisco. CDP runs SNAP (Sub network Access Protocol) at the Data Link Layer. Two Cisco devices running two different Network layer protocol can still communicate and learn about each other.

57. Show IP protocol: This command will show information on RIP timers including routing update timer (30sec default), hold-down timer (default 180sec). It also displays the number of seconds due for next update (this is fraction of update timer). This command also gives the network number for which IP RIP is enabled, Gateway, and the default metric.

1. Show IP route: This command will display the IP routing table entries. In addition, it displays the Gateway of last resort (if one is assigned). It also displays the codes used for various types of routes. Some of the important codes are:

C: directly connected;

S: Statically connected

I : IGRP

R : RIP

2. Show IP interface: This command shows you interface-wise information such as IP address assigned to each interface, whether the interface is up, MTU etc.

3. Debug IP RIP: Debug IP RIP will turn the RIP debugging ON. This will display a continuous list of routing updates as they are sent and received. This leads to lot of overhead, which is the reason that you use "undebug ip rip" to turn-off debugging as soon as you finish with debugging.

58. Cisco router boot configuration commands:

1. boot system - This is a global command that allows you to specify the source of the IOS software image to load. If you configure more than one source, attempts are made to load the IOS from the first command in the configuration to the last successively. If the first fails, the second boot command is used.

2. boot system rom - Loads IOS from ROM.

3. boot system flash - Loads the first file from flash memory.

4. boot system tftp <> - Loads IOS with a filename from a TFTP server.

Cram Exam Notes 4 Cisco Certified Network Associate CCNA

40. There are five different types of passwords:

1. ENABLE PASSWORD - A global command that restricts access to privileged exec mode. This is a non-encrypted password.

2. ENABLE SECRET - Assigns a one-way encryptographic secret password, available in versions 10.3 and up. This secret password is used instead of the enable password when it exists.

3. Virtual Terminal Password (vty password): The virtual terminal password is used for Telnet sessions into the router. The password can be changed at any time. It can be set up when you configure the router from the console. There can be five distinct passwords corresponding to each vty (vty0 to vty4) or there can be a single password for all vtys.

4. Auxiliary Password: Auxiliary password is used to set password to the auxiliary port. This port is used to access a router through a modem.

5. Console Password: Console password is used to set the console port password.

41. Internal memory components of a Cisco router:
. ROM (Read Only Memory); Memory containing micro-code for basic functions to start and maintain the router. ROM is not typically used after the IOS is loaded.

2. RAM/DRAM : stores the running configuration, routing tables, and packet buffers. Some routers, such as the 2500 series, run IOS from Flash, not RAM.

3. NVRAM (Non-Volatile Ram): Memory that does not lose information when power is lost. Stores the system’s configuration file and the configuration register. NVRAM uses a battery to maintain the data when power is turned off.

4. Flash Memory: Stores the compressed IOS (IOS stands for Cisco Internetwork Operating System) image. Flash memory is either EEPROM or PCMCIA card. Flash memory enables you to copy multiple versions of IOS software. This allows you to load a new level of the operating system in every router in your network and then, to upgrade the whole network to that version at an appropriate time.

42. While a packet travels through an Internetwork, it usually involves multiple hops. Note that the logical address (IP address) of source (that created the packet) and destination (final intended destination) remain constant, the hardware (Interface) addresses change with each hop.

43. Default administrative distances some important routing protocols are as below:

Route Source Default Distance

Directly connect Interface 0

Static Route 1

IGRP 100

RIP 120

Unknown 255

An administrative distance of 0 represents highest trustworthiness of the route.

An administrative distance of 255 represents the lowest trustworthiness of the route.

Routed and Routing protocols:

- Routing protocols job is to maintain routing tables and route packets appropriately. Examples of routing protocols are RIP, IGRP, EIGRP, OSPF. Routers can support multiple independent routing protocols and can update and maintain routing tables for each protocol independently.

- Routed protocols are used to transport user traffic from source node to destination node. Examples of routed protocols are IP, IPX, AppleTalk.

44. There are three ways a router learns how to forward a packet:

1. Static Routes - Configured by the administrator manually. The administrator must also update the table manually every time a change to the network takes place. Static routes are commonly used when routing from a network to a stub (a network with a single route) network.

The command is

ip route network mask address/interface [distance]

ex: ip route 165.44.34.0 255.255.255.0 165.44.56.5

Here, 165.44.34.0 is the destination network or subnet

255.255.255.0 is the subnet mask

165.44.56.5 is the default gateway.

2. Default Routes - The default route (gateway of last resort) is used when a route is not known or is infeasible. The command is

ip route 0.0.0.0 0.0.0.0 165.44.56.

The default gateway is set to 165.44.56.5

3. Dynamic Routes - In dynamic routing, the routing tables are automatically updated. Dynamic routing uses broadcasts and multicasts to communicate with other routers.

The commands to enable rip are:

router rip

network .

45. To enable the Cisco IOS to forward packets destined for obscure subnets of directly connected networks onto the best route, you use "ip classless" command.

46. There are broadly three types of routing protocols:

1. Distance Vector (Number of hops) - Distance vector routing determines the direction (vector) and distance to any link in the internetwork. Typically, the smaller the metric, the better the path. EX: Examples of distance vector protocols are RIP and IGRP. Distance vector routing is useful for smaller networks. The limitation is that any route which is greater than 15 hops is considered unreachable. Distance vector protocols listen to second hand information to learn routing tables whereas, Link state protocols build routing tables from first hand information. Routers with distance vector protocols send its entire routing table to each of its adjacent neighbors.

2. Link State Routing: Link State algorithms are also known as Shortest Path First (SPF) algorithms. SPF generates the exact topology of the entire network for route computation, by listening to the first hand information. Link State protocols take bandwidth into account using a cost metric. Link State protocols only send updates when a change occurs, which makes them more efficient for larger networks. Bandwidth and delay are the most widely used metrics when using Link-State protocols. EX: OSPF and NLSP.

Benefits of Link State protocols:

1. Allows for a larger scalable network

2. Reduces convergence time

3. Allows “supernetting”

3. Balanced Hybrid - Balanced Hybrid combines some aspects of Link State and Distance Vector routing protocols. Balanced Hybrid uses distance vectors with more accurate metrics to determine the best paths to destination networks. EX: EIGRP.

47. Distance vector protocol depends only on Hop count to determine the nearest next hop for forwarding a packet. One obvious disadvantage is that, if you have a destination connected through two hops via T1 lines, and if the same destination is also connected through a single hop through a 64KBPS line, RIP assumes that the link through 64KBPS is the best path!

48. RIP (and IGRP) always summarizes routing information by major network numbers. This is called classfull routing.

49. Convergence is the term used to describe the state at which all the internetworking devices, running any specific routing protocol, are having identical information about the internetwork in their routing tables. The time it takes to arrive at identical information of the internetwork is called Convergence Time.

50. RIP,RIP2, and IGRP use distance vector algorithms.

RIP2 transmits the subnet mask with each route. This feature allows VLSM (Variable Length Subnet Masks) by passing the mask along with each route so that the subnet is

Cram Exam Notes 3 Cisco Certified Network Associate CCNA

31. Ethernet_II has a type field to identify the upper-layer protocol. 802.3 has only a length field and can't identify the upper-layer protocol.

32.To find valid hosts given an IP address (say 156.16.3.52) and a subnet mask (sat a 12-bit subnet). The valid hosts are determined as below:

A 12-bit subnet mask gives us 255.255.255.240; 4094 subnets, each with 14 hosts. (Host addresses of all zeros and all 1s can't be assigned). The 156.16.3.52 is in the 48 subnet range. The valid range is through 49 - 62. 63 is a broadcast address.

Here is how you get the subnet range:

1. Find the subnet mask. In this case, default subnet mask for Class B address is 255.255.0.0. There are additional; 12 bits in the subnet mask. Now the subnet mask looks like:

11111111.11111111.11111111.11110000. This is equal to 255.255.255.240.0.

2. Now, deduct the lowest value octet (Which is non zero), from 256. Here, (256-240)=16.

This is the value that the subnets are incremented. Therefore, you will have hosts with values from:

156.16.3.1 to 156.16.3.14 (All 0s and all 1s host addresses can not be used)

156.16.3.17 to 156.16.3.30

156.16.3.33 to 156.16.3.46

156.16.3.49 to 156.16.3.62 and so on.

It is important to know that subnets are incrementing here by a factor of 16.

33. The following are some important commands that can be used to edit and review command history buffer on a Cisco router. It will be useful to practice these commands.

A : Move to the beginning of the command line

E : Move to the end of the command line

F : Move forward one character, same as using "Right Arrow".

B : Move backward one character, same as using "Left Arrow".

P : Repeat Previous command, same as using "Up Arrow".

N : Repeat Next (more recent) command, same as using "Down Arrow".

B : Moves to beginning of previous word.

F : Moves to beginning of next word.

R : Creates new command prompt, followed by all the characters typed at the last one.

34. The following are some frequently used COPY commands:

1. COPY RUNNING-CONFIGURATION STARTUP-CONFIGURATION (alternatively, you can use an older version of the command, WRITE MEMORY): This command saves the current configuration to NVRAM. Alternatively, we can issue the command using short form: COPY RUNNING STARTUP - Copies configuration from RAM to NVRAM
2. COPY STARTUP RUNNING - This command merges configuration from NVRAM to RAM.
3. COPY FLASH TFTP - Copies current IOS from router flash memory to TFTP server.
4. COPY TFTP FLASH - Copies image file from TFTP server to flash. This is used to upgrade the IOS image file to a newer version, or if your IOS image becomes corrupt.

35. The banner is displayed whenever anyone logs in to your Cisco router. The syntax is

- "banner motd # " . MOTD stands for "Message Of The Day".

# symbol signifies the start of the banner message to the router. You will be prompted for the message to be displayed. You need to enter "#" symbol at the end of the message, signifying that the message has ended.

36. Router modes of operation:

1. User EXEC mode (Prompt: Router>):- This is the LOWEST level of access. This allows examination of router status, see routing tables, and do some diagnostics. However, you cannot change the router configuration, view the configuration files, or control the router in any way. The prompt in this mode is "Router>".

2. Privileged (enable) EXEC mode (Prompt: Router#):- This mode allows you to have all the privileges of EXEC (user) mode plus commands that enable you to view configuration files, change the router configuration, perform troubleshooting that could potentially disrupt traffic. The default prompt for this mode is "Router#".When you are working in the privileged mode (at # prompt), you can get back to user mode by typing "disable" at the "#" prompt.

3. Global Configuration mode (Prompt: Router (Config)#):-

Global configuration mode allows you to perform tasks that affect the entire router, such as naming the router, configuration of banner messages, enabling routed protocols, and generally anything that affects the operation of the entire router.

When you first switch on a router, you enter Setup mode. Setup mode is different from configuration mode in that setup mode appears when there is no configuration file present. Upon entering setup mode, you can supply some basic configuration parameters to Cisco router.

37. You can use "tab" to complete the command that you are typing.

38. SHOW command is extensively used for seeing the status and configuration information of the router.

Some of the frequently used commands are:

1. SHOW RUNNING-CONFIGURATION -This command displays the router's active configuration file, passwords, system name, and interface settings, interfaces IP addresses etc.

2. SHOW INTERFACE - Shows status and configuration information of the local interfaces. The first line says something like “TokenRing1 is up, line protocol is up”. The first part “TokenRing1 is up” describes the physical layer components such as electrical cabling and signaling are OK. The second part “line protocol is up” means that the router is detecting keep-alive messages. The router may be put into administratively down status, at which point the line would read, “TokenRing1 is administratively down, line protocol is down.”

3. SHOW INTERFACE SERIAL 0 - Shows the serial 0 configuration.

4. SHOW INTERFACES - Displays statistics for all interfaces configured on the switch.

5. SHOW PROCESS - Displays a router’s CPU utilization.

6. SHOW CONFIG - Displays information on the startup configuration.

7. SHOW VERSION - Displays information about the system hardware (RAM/ROM), software version, names of configuration files, and boot-images. This command will also show the current configuration register value.

39. The Cisco router can be configured from many locations.

1. Console port: During the initial installation, you configure the router from a console terminal connected to the "Console port" of the router.

2. Virtual Terminals (vty): A virtual terminal (vty) is typically accessed through Telnet. A router can be accessed through vty after it the initial installation in the network. There are five virtual terminals, namely, vty0,vty1,vty2,vty3,vty4.

3. Auxiliary Port: you can configure a router through auxiliary port. Typically, a modem is used to configure the modem through aux port.

4. TFTP Server: Configuration information can be downloaded from a TFTP server over the network.

5. NMS (Network Management Station): You can also manage router configuration through NMS such as CiscoWorks or HP OpenView.

40. There are five different types of passwords:

1. ENABLE PASSWORD - A global command that restricts access to privileged exec mode. This is a non-encrypted password.

2. ENABLE SECRET - Assigns a one-way encryptographic secret password, available in versions 10.3 and up. This secret password is used instead of the enable password when it exists.

3. Virtual Terminal Password (vty password): The virtual terminal password is used for Telnet sessions into the router. The password can be changed at any time. It can be set up when you configure the router from the console. There can be five distinct passwords corresponding to each vty (vty0 to vty4) or there can be a single password for all vtys.

4. Auxiliary Password: Auxiliary password is used to set password to the auxiliary port. This port is used to access a router through a modem.

5. Console Password: Console password is used to set the console port password.

Cram Exam Notes 2 Cisco Certified Network Associate CCNA

12. Telnet, FTP, and TFTP:

1. Telnet is used for terminal emulation that runs programs remotely. Telnet uses TCP/IP protocol.

2. Telnet requires a username and password to access.

3. FTP (File Transfer Protocol) is a connection oriented protocol. It uses TCP/IP for file transfer. Compare this with TFTP (Trivial File Transfer Protocol) that uses UDP (Connectionless protocol). SNMP uses UDP over IP. Tracert, Ping use ICMP as their base protocol. FTP is used to transfer files.

13. Maximum hop count supported by RIP is 15.

14. The port numbers used by different programs are as below:

I. FTP : Port #21

II. Telnet: Port #23

III. SMTP: Port #25

IV. SNMP: Port #161

It is important to know that FTP, Telnet, SMTP use TCP; whereas TFTP, SNMP use UDP.

15. SNMP is part of TCP/IP protocol suite. It allows you to monitor and manage a network from a centralized place by using SNMP Manager software. The systems or devices that provide the responses are called agents (or MIBs). An SNMP agent is any computer running SNMP agent software.

MIB stands for Management Information Base. It is part of SNMP agent database. A MIB records and stores information abut the host it is running on. An SNMP manager can request and collect information from an agent's MIB. Routers are typical MIB agents. SNMP agent generates "trap" messages that are then sent to an SNMP management console, which is a trap destination.

17. Address Resolution Protocol (ARP) is used to resolve or map a known IP address to a MAC sub layer address to allow communication on a multi-access medium such as Ethernet. Reverse ARP (RARP) is used to obtain an IP address using an RARP broadcast. RARP can be used to boot diskless workstations over a network.

18. The 7 layers of OSI model are:

1. The Application Layer: Application layer is responsible for identifying and establishing the availability of desired communication partner and verifying sufficient resources exist for communication. Some of the important application layer protocols are: WWW, SMTP, FTP, etc.

2. The Presentation Layer: This layer is responsible for presenting the data in standard formats. This layer is responsible for data compression, decompression, encryption, and decryption. Some Presentation Layer standards are: JPEG, MPEG, MIDI, PICT, Quick Time, TIFF.

3. The Session Layer: Session Layer is responsible for co-ordinating communication between systems/nodes. The following are some of the session layer protocols and interfaces: a) Network File System (NFS), SQL, RPC (Remote Procedure Call), X-Windows, ASP, DNA SCP.

4. The Transport Layer: The Transport Layer is responsible for multiplexing upper-layer applications, session establishment, and tearing-down of virtual circuits. This layer is responsible for flow control, to maintain data integrity.

5. The Network Layer: There can be several paths to send a packet from a given source to a destination. The primary responsibility of Network layer is to send packets from the source network to the destination network using a pre-determined routing methods. Routers work at Network layer.

6. The Data Link Layer:

Data Link Layer is layer 2 of OSI reference model. This layer is divided into two sub-layers:

A. Logical Link Control (LLC) sub-layer.

B. Media Access Control (MAC) sub-layer.

The LLC sub-layer handles error control, flow control, framing, and MAC sub-layer addressing.

The MAC sub-layer is the lower of the two sub-layers of the Data Link layer. MAC sub-layer handles access to shared media, such a Token passing or Ethernet.

7. Physical Layer: The actual flow of signals take place through Physical layer. At Physical layer, the interface between the DTE and DCE is determined. The following are some of the standard interfaces are defined at Physical layer: EIA/TIA-232, EIA/TIA-449,V.24,V.35,X.21,G.703,HSSI (High Speed Serial Interface).

19. Repeaters, Bridges, and Routers:

I. Repeaters work at Physical layer (Layer 1),

II. Bridges and simple switches work at Data Link Layer (Layer 2),

III. Routers work at Network Layer (Layer 3) of ISO Reference Model. 20. CSU / DSU is an acronym for Channel Service Unit / Data Service Unit. CSU/DSU is part of Customer Premise Equipment (CPE). CSU / DSU connect to a Central Office (CO), a telephone switching company located nearer to the customer.