Email: andrea.johnen@gmail.com

EDUCATION

• 2010 CCNA: Security, UPSA Network Academy, Universidad Privata Santa Cruz de la Sierra
• 2006 – 2007 Graduate Diploma in Auditing & IT Security (Assessed by NZQA), Universidad Autónoma Gabriel Rene Moreno, Santa Cruz, Bolivia
• 2001 – 2005  Degree in System Engineering (Assessed by NZQA), Universidad Católica Boliviana, San Pablo, Santa Cruz, Bolivia

OBTAINED CERTIFICATIONS

• Valid until 2013 Cisco Certified Entry Networking Technician (CCENT), Cisco Certified Network Associate (CCNA), CCNA:   Security

TECHNICAL SKILLS

• OS: Windows XP, Windows Vista, Cisco IOS
• Network Hardware: Cisco Routers/Switches
• Routing Protocols: RIP, OSPF, EIGRP, BGP
• LAN/WAN Technologies: Frame Relay, Ethernet, VLAN
• Security: Access Lists, SSH, 3DES, RADIUS, IPSec
• DataBase: MySQL
• Design and Web Technology: FireWorks, Flash, Dreamweaver
• Programming Languages: Java, Visual Basic, Visual Basic.NET, CSharp, Borland Delphi
• Office Programs: MS-OFFICE (Word, Excel, Access, PowerPoint, Project, Publisher)
• Tools: WireShark, Security Device Manager (SDM), ISA Server, ACL, IDEA

WORK EXPERIENCE

2009 to date Helibol S.R.L., IT Consultant

• Web Application Development for the Company’s processes using J2EE technology.
• Implementation and administration of the Company’s Intranet using opensource technology (open atrium).
• Redisign and translation (English-Spanish) of the Company’s Web Site.
• IT Support (email, PCs, Servers, etc)
• Development of policies and procedures for the IT department.

2008 to 2009 Artha Solutions S.R.L, System Auditor & IT Consultant

• Provide advice on issues related to technical support, networks, systems development, security and auditing systems.
• Oversee and coordinate development projects in information systems.
• Develop training materials for the Virtual Classroom.
• Elaboration of proposals on the services offered by the Company to be presented to customers and / or be presented in bids.

2006 – 2007 PricewaterhouseCoopers S.R.L., Assistant of Advisory – SPA System and Process Assurance

• Assisted as part of the System Audit Team, participating IT security assessments, evaluating technology environments for various companies.

July 2004 Centro Educativo Contacto Global S.A., Professional Intership of System Engineering

• Analysis and design of a registration courses System

LANGUAGE SKILLS

• Spanish Native
• English IELTS Overall Band Score 7.0, January 2009
• French Basic Level, French Alliance, 2007
• Italian Basic Level, Italian Circle, 2007

Feel free to add me to your google, I’ll be happy to assist you regarding Networks and & Security

show controllers
Command used to see if clocking stopped on an interface.
Command that will show whether a DTE or DCE cable is plugged into serial 0.

show interface
The most useful IOS command when troubleshooting media issues & port access issues.

erase-startup-config
Deletes the configuration stored in NVRAM.

copy flash tftp
Used to copy a configuration from a router to a TFTP host.

clock rate 64000
Provides the router with a 64kbps serial link.

show version
Displays a router’s configuration registry settings.

exec-timeout 15 30
Set the console session timeout to 15 minutes and 30 seconds.

show user
Used to see who has telnet sessions to your router.

Ctrl-Shift-6.. then X key sequence
Used to suspend a telnet session.

ip route 186.157.5.0 255.255.255.0 10.1.1.3
The router should use address 10.1.1.3 to get to devices on network 186.157.5.0

show ip route
Displays information about static route configuration on a Cisco router.

encapsulation ppp
Output from the show interface command that indicates that ppp is confired properly.

disconnect
Suspend Telnet session.

router(config)# router rip
Specifies RIP as the routing protocol.

show cdp neighbors detail
Produces the same result as the show cdp neighbors

show cdp interface
Displays the frequency at which packets are sent. Information included in the output encapsulation type.

shwo cdp entry
Displays the device platform of a directly connected device.

show cdp traffic
Displays CDP packet checksum errors.

no cdp run
command htat disables CDP on the device as a whole.

no cdp enable
Disable CDP on a single interface.

What will be displayed by CDP
Device name and connected device.
IP address of connected device.
Capabilities of connected device.

“undebug all” or “un all” for short
Command that will stop the debug outputs from displaying on the screen.

copy startup running
Merges a configuration file from NVRAM into the configuration in RAM.

show ip protocols, show ip route
Displays information about routing protocols and the routing table.

debug ip rip
Displays information on RIP routing transactions.

reload
Command used if you want to totally reinitialize the router and replace the current running-config with the current startup-config.

service password-encryption
From global configuration mode, will encrypt the passwords.

erase start
Will delete the contents of NVRAM on a router.

traceroute
Can be used from user mode or privileged mode, is used to find the path a packet takes through an internetwork and will also show you where the packet stops because of an error on a router.

show flash
Provide you with the curent IOS name and size and the size flash memory.

show hosts
Provides information on temporary DNS entries and permanent name-to-address mappings created using the ip host command.

show mac-address table
Displays the forward/filter table on the switch.

0×2102
Tells the router to look in NVRAM for the boot sequence.

Configure the same default route
0.0.0.0 0.0.0.0 specify the next hop
0.0.0.0 0.0.0.0 exit interface instead of the next hop
ip default-network nro of IP

(config-router)#passive-interface
Stops updates from being sent out an interface, but route updates are still received.

ip route 172.16.4.0 255.255.255.0 192.168.4.2
The command is used to established a static route.
The default administrative distance is used.

login banner
Customized text that is displayed before the username and password login prompts.

Interface configuration mode
Mode to enter the command to specify PPP authentication.
Ude to configura a particular port on a switch.

CLI Commands Statements

• It is best to use debug commands during periods of lower network traffic and fewer users.
• On a heavily used production router, enabling a debug privileged EXEC command can be harmful.
• From global configuration mode, you set the default gateway with ip default-gateway, which allows you to manage the switch remotely.

shutdown
IOS command used to increase security of unused switch ports.

C2800nm-ipbase-mz.124-5a.bin
c2800nm: Platform in which the image runs.
ipbase-mz: Where the image runs and whether the file is compressed.
124-5a: Version number.
.bin: File extension.

QA
Q: If you determine that the appropriate translation is not installed in the translation table while troubleshooting a NAT connectivity problem on a Cisco router:
A: Determine ifn you have enough addresses in the NAT pool. Verify that the router interfaces are appropriateley defined as NAT inside or NAT outside. Verify that the ACL referenced by the NAT command is permitting all necessary inside local IP addresses.
]]> http://atcj.wordpress.com/2010/03/23/cli-commands/feed/ 0 atcj http://atcj.wordpress.com/2010/03/23/cisco-installation/ http://atcj.wordpress.com/2010/03/23/cisco-installation/#comments Tue, 23 Mar 2010 15:45:23 +0000 atcj http://atcj.wordpress.com/?p=251 ]]> Terminal Programs
Hyperterm (Microsoft)
Tera Term
Minicom
Secure crt

Setting the terminal to connect via COM port

• Band Rate: 9600
• Data Bits: 8
• Parity: None
• Stop Bits: 1
• Flow Control: None

NVRAM
Cisco router component used primarily to store the startup config file.

ROMMON
Low level operating system normally used for manufacturing testing and troubleshooting.

Boot field value 0×2
Checks the startup-config file for boot sysem commands.

Installation Statements

• Upon initial installation of a Cisco Switch or router, the network administrator typically configures the networking devices froma TFTP server.
• on most routers, the Cisco IOS software is loaded into RAM to run, but on some routers, it is run directly form flash memory.
• A router does not have a default configuration.

Physical Catalyst Switch startup process

1. Verify that all cable connections are secure, the terminal is connected to the console port, and the console terminal application is selected.
2. Attach the power cable plug to the switch power supply socket.
3. Observe the boot sequence, including the cisco IOS software output text on the console.

Methods used to mitigate configuration issues
Secure the configuration, verify the cahnges before you save, know what you have before you start.

Cisco Installation Statements

• Routers have a startup process where they test the hardware and load the operating system and configuration.
• Basic router configuration is usually done through the console port using CLI and consists of: Host address, Interface addressing.
• The Cisco DHCP server is a full DHCP server that can be configured using SDM.
• The Cisco IOS provides a set of tools for remote accessing and testing: Telnet, SSH, ping, traceroute.
• All Cisco routers have a default configuration register setting of 0×2102, which tells the router to load the IOS from flash memory and the configuration from NVRAM.
• If you save a configuration and reload the router and it comes up either in setup mode or as a blank configuration, chances are you have the configuration register setting incorrect.

When a router boots up
It performs a series of steps, including performing tests, finding and loading the Cisco IOS software, finding and loading configurations, and running the Cisco IOS software.

Cisco IFS feature
Provides a single interface to all the file systems that a router uses. As any network grows, storage of Cisco IOS images and configuration files on a central TFTP server enables control of the number and revision level of Cisco IOS images and configuration files that must be maintained.

To Telnet to a remote switch
The switch must have a default gateway configured so that the switch will be able to send Telnet return traffic back to you.

QA
Q: How to start a Catalyst 2950 series switch?
A: Attach the power cable plug to the switch power supply socket.

Q: If the POST completes successfully on a Catalyst Switch, what display could you see on the console?
A: The > promt.

Q: How to power up a Cisco router.
A: Turn the power switch to “on”

Q: To connect to a router or switch console port, you would use:
A: An RJ45 rolled cable.

Q: When you start a Cisco router, you should see on the console:
A: Cisco IOS software output text.

Q: Primary purpose of setup mode on a Cisco Router:
A: To bring up a minimal feature configuration.

Q: Cisco IOS command used to return to user EXEC mode from the privileged EXEC mode:
A: disable.

Q: If you enter a major command on a Cisco router:
A: The router switches you from one configuration mode to another.

Q: the lowest 4 bits of the configuration register value:
A: Make up the boot field.

Q: Find and Load Configuration
A: Stage during a Cisco router bootup that occurs last.

Q: Before you start to configure the router:
A: You should erase the NVRAM with the erase startup-config command, and then reload the router using the reload command.

Q: Type of device you typically configure the clock rate
A: CSU/DSU

Port-Security
IOS command that can be used to control access to a switch port based on a MAC address.
Stop unauthorized users from accessing the LAN.

Port-Security options available on a 2950 switch
Shutdown, restrict, protect.

Three modes of port-based security
Restrict, Shutdown, Protect.

Can be protected with a password
Console access, vty access, tty access, EXEC-level access.

4 Typical types of DoS
TCP SYN flood, ping of death, Tribe Flood Network, and Stacheldraht.

Application Layer Attacks
Commonly zero in on well-known holes in the software that’s typically found running on servers. Favorite targets include FTP, sendmail, and HTTP.

Security Statements
Before you back up an IOS image to a laptop directly connected to a router’s Ethernet port, make sure the TFTP server software is running on your laptop, that the Ethernet cable is a “crossover”, and that the laptop is in the same subnet as the router’s Ethernet port, and then you can use the copy flash tftp command from your laptop.

0×2142
Is one of the steps in password recovery.

802.11i
Defines a set of standard protocols for authentication, dynamic key exchange, and encryption using AES.

Network Admission Control (NAC)
Checks all end stations before they attach a network to ensure policy compliance.

FTP, Telnet
Use TCP at the Transport Layer. However, they both are Application Layer Protocols.

Common Ports
FTP: 20,21
SSH: 22
Telnet: 23
DHCP: 67, 68
HTTP: 80
NTP: 123
SNMP: 161
HTTPS: 443

QA
Q: Problems from unsuccessfully telnetting into a remote device.
A: Access control list is filtering Telnet, the vty password is missing.

Q: 802.1x EAP
A: Uses RADIUS

Q: Proprietary applications
A: Use registered ports.

IEEE
Regulatory agency that controls the 801.11 standard that governs WLANs.

Wi-Fi
Organization that offers certification for interoperability among vendors of 802.11 products.

2.4Ghz & 5Ghz band
Unlicensed band used by WLANs.

WLANs
Cannot detect a collision. Instead. WLANs use the Ready To Send (RTS) and Clear To Send (CTS) protocols to avoid collisions.

802.11b – Direct Sequence Spread Spectrum (DSSS)
Frequency band: 2.4Ghz.
3 channels.
DSSS Transmission Data Rates in Mbps: 1, 2, 5.5, 11. 150 feet.

802.11a – Orthogonal Frequency Division Multiplexing (OFDM)
Frequency band: 5Ghz.
23 channels.
OFDM Transmission Data Rates in Mbps: 6, 9, 12, 18, 24, 36, 48, 54. 65-75 feet.

802.11g – (DSSS and OFDM)
Frequency band: 2.4Ghz.
3 channels.
DSSS Transmission Data Rates in Mbps: 1, 2, 5.5, 11
OFDM Transmission Data Rates in Mbps: 6, 9,12, 18, 24, 36, 48, 54. 90-100 feet.

WPA
Uses PSK to include authentication and can use either static or dynamic encryption keys. The benefit of WPA over static WEP key is that WPA can range dynamically while the system is used.

WPA2
Uses the Advanced Encryption standard (AES) known as the counter mode cipher block chaining message authentication code (CBC-MAC) protocol (CCMP).

Wireless Statements

• The different 802.11 standards identify the characters of the transmissions used by WLANs, while the Wi-Fi certification ensures compatibility between devices.
• To address common threats to WLAN services, security has evolved to include 802.1x and WPA/WPA2
• Wireless implementations are affected by distance, speed, and form factors.

Cisco Secure Services Client
Full-featured supplicant for both wired and wireless client.

Cisco compatible extensions
More advanced wireless client features than those of native operating systems.

WZC
Windows operating systems basic wireless supplicant client.

IBSS
Set of services used to allow devices to connect directly to each other using radio waves.

ESS
A group of access points create one WLAN covering a larger area than one access point could cover.

Infrastructure
WiFi connection where devices connect to each other via an access point, and are also capable of connecting to the internet or other networks.

QA
Q: Factor that determines which access point a client associates with.
A: The access point that is received with the strongest signal.

Q: The basic service area.
A: Physical area of radio frequency coverage provided by an access point.

Q: The ability to shift data rates.
A: Strategy that enables a client to communicate while moving.

Q: 802.11g uses DSS.
A: Only if an 802.11b device is on the same network.

• Use the services of carriers such as telephone companies, cable companies, satellite systems, and network providers.
• Generally carry limited types of data at high speeds.
• Connect devices that are in a small geographic area.

A WAN Communication is used
When a department needs to share large data files quickly, and when workers within a branch of a large company need to share project data with each other.

Data Link Protocols in a WAN

• Many Data Link Layer protocols use a framing mechanism similar to HDLC.
• Define how data is encapsulated for transmission to remote sites, and also the mechanisms for transferring the resulting frames to establish the connection across the communication line from the sending to the receiving device.

Cable Connections

• The original purpose of the multimedia Cable Network System Partners Ltd. was to define a product and system standard capable of providing data and future services over CATV plants.
• Cable modems enable two-way, high speed data transmissions using the same coaxial lines that transmite cable television.
• Cable modems access providers speeds superior to leased lines, with lower costs and simpler installation.

Considerations for PSTN as a Communications Link

• Other than a modem, no additional equipment is required.
• The cost associated with the implementation of a PSTN connection link for a WAN is relatively slow.
• The maintenance of a public telephone network is very high quality with few instances in which lines are not available.

ISDN
Is considered a layer 3 WAN technology. Cisco considers PPP HDLC, and Frame Relay the most common WAN technologies.

Point-to-Point Communication Link

• Provides a single, pre-established WAN communications path from the customer premises through a carrier network, such as telephone camapy, to a remote network.
• Carriers usually lease point-to-point lines, which is why point-to-point lines are often called leased lines.
• The carrier dedicates fixed transport capacity and facility hardware to the line of a customer.
• Require minimal expertise to install and maintain.
• Usually offer a high quality of service.
• Provide permanent dedicated capacity that is always available.

PPP Statements

• When PPP connections are started, the links go through three phases of session establishment: link stablishment, authentication phases, and the Network Layer protocol phase.
• PPP provides dynamic addressing, authentication using Password Authentication Protocol (PAP) or Challenge Handshake Authentication Protocol (CHAP), and callback services.
• LCP provides a method of establishing, configuring, maintaining, and terminating the point-to-point connection. At startup, LCP provides link establishment.
• LCP protocol sometimes referred to as the manager of a PPP connection

HDLC
Is Cisco proprietary, and you cannot have HDLC on one side of a link and PPP or Frame Relay on the other side.
Is the default encapsulation for a Cisco router serial interface.

Functions of HDLC

• Includes support for both point-to-point and multipoint configurations.
• Specifies an encapsulation method for data on synchronous serial data links using frames character and checksum.
• The Cisco proprietary HDLC make it possible for multiple network layer protocols to share the same serial link by adding a new type field.

Functions of Circuit Switch Networks

• A dedicated physical circuit is established, maintained, and terminated through a carrier network for each communication session.
• Allows multiple sites to connect to the switched network of a carrier and communicate with each other.
• ISDN is an example of a circuit-switched network.

Functions of a Packet-Switching WAN Communication Link

• The route that the packets take to reach the destination site varies.
• Packet switched networks send data packets over different routes of a shared public network owned by a carrier to reach the same destination.
• The cost of a packet-switched network to the customer is generally lower than with point-to-point leased lines.

DSL

• Is a circuit switched connection technology that uses existing twisted pair telephone lines to transport high-bandwidth data, such as multimedia and video, to service subscribers.
• Allows use of the local-loop line for normal telephone voice connection and an always-on connection for instant network connectivity.
• Place upload (upstream) and download (downstream) data transmissions at frequencies above a 4KHZ window, allowing both voice and data transmissions to occur simultaneously on a DSL service.

Types of DSL
ADSL, IDSL.

Considerations of DSL
Can be incrementally added in any area, has distance limitations, is not universally available in all geographic locations.

Frame Relay

• The connection to the network edge is often a leased line, but dialup connections are available from some providers using ISDN or XDSL lines.
• Implements no error or flow control.
• Provides both PVC and SVC service using shared medium-bandwidth connectivity that carries voice and data traffic.
• If you only have one free serial interface on your router, you can use Frame Relay to connect multiple remote sites.

Frame Relay LMI types
Cisco, Q933A, ANSI.

ATM

• Cell switched technology.
• Implemented using virtual circuits.
• Virtual circuits provide a bidirectional communications path from one ATM end-point to another.
• Is a type of cell switched connection technology that is capable of transfering voice, video, and data through private and public networks.

Bandwidth available for WAN connections

• In North America, bandwidth is usually expressed as a “DS” number (DS0, DS1, and so forth) that technically refers to the rate and format of the signal.
• The bandwidth on a serial connection can be incrementally increased to accomodate the need for faster transmission.
• Bandwidth refers to the rate at which data is transferred over the communication link.

PVC
In a fully meshed environment, every router has a PVC defined to every other router and in a Non-fully meshed environment (or hub and spoke) PVCs are only defined between routers that need to communicate.

Ethernet 802.3
CSMA/CD process, specifies the physical layer, specifies the MAC portion of the Data Link Layer.

Ethernet Frame (IEEE 802.3)

Cable Connections
T568-A

T568-B

Cable Categories:

• Category 1: Telephone communications.
• Category 2: Transmiting data at speeds up to 4Mbps.
• Category 3: 10Base-T networks. Can transmit data up to 10Mbps.
• Category 4: Token Ring. 16Mbps
• Category 5: 100Mbps
• Category 5e: 1000 Mbps (1Gpbs)
• Category 6: Consists of 4 pairs of 24-gauge copper wires. 1000Mbps

Ethernet 10Base-T
At the workgroup level, provides connectivity between the end user and workgroups. Provides interswitch connectivity for low-to-medium volume applications.

1000Base-Lx
It specifies the use of fiber-optic cable.

Fast Ethernet
At the end-user level, gives high-performance PC workstations 100Mbps access to a server. At the workgroup level, provides high-performance connectivity to the enterprise server. At the backbone level, provides backbone and interswitch connectivity.

Gigabit Ethernet
Not typically used at the end-user level. At the end-user level, provides backbone and interswitch connectivity between the end-user and the user-lever switch.

Half Duplex Ethernet
Operates in a shared collision domain, and it has a lower effective throughput than full duplex.

Full Duplex
Means you are using both wire pairs simultaneously to send and receive data. You must have a dedicated switch port for each node, which means you will not have collisions. Both the host network card and the switch port must be capable and set to work in full-duplex mode.

QA
Q: What is the minimum category of UTP required for Ethernet 1000Base-T?
A: Category 5.

Subnetting
In the CBTNuggets (640-822) this is the technique they use.

1. Determine number of networks and convert to binary
2. Reserve bits in subnet mask and find your increment.
3. Use increment to find your network ranges

• Substract when finding networks
• Add when finding hosts

Subnetting Statements

• A /30, regardless of the class of address, has a 252 in the fourth octet. This means we have a block size of 4 and our subnets are 0, 4, 8, 12, 16, etc. Address 14 is obviously in the 12 subnet.
• A point-to-point link uses only two hosts. A /30, or 255.255.255.252 mask provides two hosts per subnet.

Let’s practice
Let’s practice some subnetting and see if you feel comfortable with the technique. I don’t know if you have played the binary game from the Cisco Learning Network, let me tell you is addictive and educational. Anyways… let’s start.

• Which of the following addresses can be assigned to a host when using a subnet mask of 255.255.254.0?

1. 113.10.4.0
2. 186.54.3.0
3. 175.33.3.255
4. 26.35.2.255
5. 152.135.7.0
6. 17.35.36.0

Ok, first things first, the subnet is telling us to concentrate only in the 3rd and 4th octet. The 3th octed is telling us that there is an increment of 2 for each subnet. So, we have X.X.0.0 as our network address and X.X.1.255 as our broadcast. With this knowledge, we can get the correct answers. Everything with a multiple of 2 in the 3th octed and 0 in the 4th octet is a network address, so that means that A and F are not our answers. Next, let’s discart the broadcast addresses, multiple of 2 minus 1 in the 3rd octet and 255 in the 4th. That means that C is not our answer either. So the correct answers must be: B, D and E.

QA
Q: Max. number of bits that can be borrowed to create a subnet for a class C network.
A: 6.

Q: A subnet mask tells the router to look at which portions of an IP address?
A: Network and subnet bits.

Q: Practical minimum number of bits that can be borrowed to form a subnet:
A: 1.

Routing Protocols
Are used between routers to determine paths and maintain routing tables.

Distance Vector Protocol

• RIP and IGRP. This protocol determines the direction (vector) and distance (hop count) to any network in the internetwork, this process is also known as “routing by rumor”.
• A distance vector router sends the entire routing table to its neighboring routers as part of a periodic routing table update.

Link-State Routing Protocol
OSPF, IS-IS. Respond quickly to network changes, send periodic updates (link-state refreshes) at long time intervals, aprox. every 30 minutes, every router tries to build its own internal map of the network topology.

RIP

• Is used in small, homogeneous networks.
• RIP updates are sent out every 30 seconds.
• The administrative distance of RIP is 120.
• Default value of the RIP hold-down timer: 180 seconds.

RIPV1

• Is a classful routing protocol.
• Sends out broadcasts to 255.255.255.255.

RIPV2

• Is a classless routing protocol. RIPV2 supports VLSM, manual route summarization, and authentication, RIPV1 does not provide these.
• Sends out multicast packets to 224.0.0.9.
• RIPV2 is pretty much just like RIPV1. It has the same administrative distance and times, an is configured just like RIPV1.

IGRP
Routing metrics used by IGRP are bandwidth, MTU, Reliability, and Load.

OSPF
OSPF routers listen to 224.0.0.5 for updates.

EIGRP
Hybrid (Vector and Link State). EIGRP updates are destined for 224.0.0.10

Administrative Distances
Static: 1
EIGRP: 90
IGRP: 100
OSPF: 110
RIP: 120

Passive command provide to dynamic routing protocols
Stops an interface from sending periodic updates but not from receiving updates.

Stub Network
Have only one connection to an internetwork. Only default routes can be set on a stub network or network loops may occur.

Path determination process

• Routers evaluate the available paths to a destination.
• The routing process uses metrics and administrative distances when evaluating network paths.
• Dynamic routing occurs when information is learned using routing information that is obtained from routing protocols.

Routing Process

1. The router receives a packet on one of its interfaces.
2. The router deencapsulates the frame and uses the protocol information of the frame to determine that the network layer packet will pass to the IP process.
3. The router checks the destination address in the IP header. Either the packet is destined for the router itself or it needs to be forwarded. If the packet needs to be forwarded, the router searches its routing table to determine where to send the packet.
4. If the destination network is on a directly attached network, the router will use the ARP process to obtain the MAC address of the host and forward it to the network segment. If the network is reachable, through another router, the router will use the MAC address of the next-hop router and forward the packet out the interface indicated in the routing table.
5. The outgoing interface process encapsulates the packet appropriately to the media and sends the packet onto the network segment.

Function of Routing Tables

• Are maintained through the transmission of MAC addresses.
• Contain metrics that are used to determine the desirability of the route.
• When a router receives an incoming packet, it uses the source address and searches the routing table to find the best path for the data from that source.

QA
Q: What does RIP version 2 add that is not found in RIP v1.
A: Authentication, summarization, multicast updates, VLSM.

Q: Contains routing information that helps a router in determining the routing path.
A: IP address, MAC addresss, Routing Table.

Q: Metrics most commonly used by routing protocols to determine a network path:
A: Hop count, bandwidth, delay.

Q: If a router does not match the appropriate address portions to a number in its routing table:
A: It discards the packet.

Q: BGP
A: An exterior gateway protocol.

Q: Administrative distance is required
A: When the same route is learned via multiple routing protocols.

Q: With RIP, load balancing is performed over multiple paths that have which characteristic:
A: Equal cost.

Q: After the path is determined.
A: A router can route a routed protocol.

Q: RIPV2 uses to prevent routing loops.
A: Split horizon, Holddown timers, triggered updates.

Q: Purpose of default route.
A: It is a route used when a packet is destined for a remote network that is not listed in the routing table.

Q: What does RIPV2 add taht is not found in RIPv1
A: Authentication, summarization, multicast updates, VLSM

Physical threat

• Someone turning off the power to the switch to block network access.
• Someone turning off the air conditioning system in the network closet.

Spanning Tree Protocol
STP assigns roles to bridges and ports to ensure that only one forwarding path exists through the network at any given time.
STP prevents Layer 2 loop in networks with redundant switched paths.

Split Horizon
Will not advertise a route back to the same router it learned teh route from.

Flow Control
Is a way for the receiver to govern how much data is sent by the sender at one time.

Types of Flow Control
Buffering, Windowing, and Congestion Avoidance.

Windowing
The sender can transmit a specific number of unacknowledged segments.

Network Communication Problems Statements

• There are a number of ways in which the performance benefits of switched Ethernet LANs can be enhanced, including microsegmentation and tiered connectivity hierarchies. However, there is a potential for intentional or unintentional physical loops that can be resolved by implementing Spanning Tree Protocol.

QA
Q: Main threat to a closed network?
A: Misuse by employees.

Q: How loops can affect performance in a switch LAN
A: Broadcast storms can be created when loops occur, preventing data from being transmitted over the network.

Q: Transition states of a port running STP.
A: Blocking, Listening, Learning, Forwarding.