network+ exam

What to know:

1. Multiple choice practice questions are good, do as many as you can. 
2. THERE ARE SIMULATIONS ON THE EXAM. 
• These simulations describe a scenario that you need to fix, what they don't do is give you operating instructions for the simulations themselves. 

Concepts to Study

• OSI Model, there are very few TCP/IP model questions 
• psychical network configuration 
• know cable ratings, their color, and their properties, their usage 
• Know important protocols & port numbers and their functions 
• Be Able To:
• compare the layers of the OSI and TCP/IP models
• Know all of the layers, the order they go in, and their fuctions 
• Classify how applications, devices, and protocols relate to the OSI model layers
• i.e. switches, routers, servers, etc. 
• Explain the purpose and properties of routing and switching
• identify common TCP and UDP default ports 
• explain the function of common networking protocols 
• 
  
• given a scenario, implement the following network troubleshooting methodology 
• idenfify virtual network components 
• in a digital model, identify  the router, switch, etc.
• Given a scenario, install and configure routers and switches
• given a scenario, install and configure a wireless network
• given a scenario, troubleshoot common wireless problems given a scenario, troubleshot common router and switch problems 
• given a scenario and a set of requirements, plan and implement a basic SOHO network 
• categorize and contrast different wireless standards 
• categorize WAN technology types and properties 
• given a scenario, troubleshoot common physical connectivity problems
• identify components of wiring distribution
• explain the purpose and features of various network applicances
• given a scenario use appropriate hardware tools to troubleshoot connectivity issues 
• given a scenario use appropriate software tools to troubleshoot connectivity issues 
• given a scenario use the appropriate network monitoring resource to anaylze traffic
• explain different methods and rationales for network performance
• given a scenario, implement appropriate wireless security measures
• explain the methods of network access security 
• explain methods of user authentication
• explain common threats vulnerabilities and mitigation techniques 
• given a scenario install and configure a basic firewall
• categorize different types of network secuiryt appliances and methods 

Exam Tomorrow!!

Network Topologies 

1. Bus
• simplest topology 
• nodes of the network are individually linked up to two successive other nodes or another node and a terminating node (terminator)  
• considered archaic 
• difficult to troubleshoot network issues
• redundancy issues 
• need for terminators 
• amount of traffic created 
• nodes linked in this topology are called "daisy-chained"
2. Ring 
• similar to bus network in that nodes are linked to each other 
• ends of a ring network are not terminated because there are no ends
• a "circular" network in which each and every node is linked to two other nodes 
• shares many of the same weaknesses as the bus topology 
• troubleshooting difficult
• redundancy 
• traffic 
• difficulty of adding a node to a token ring network
3. Star
• most typical and practical network setup 
• each node maintains an individual connection to the switch 
• traffic between each node only goes through the switch and not through other nodes 
• increases redundancy of the network 
• increases data privacy 
• reliant on the switch 
• extensive wiring necessary
4. Mesh/Ad-Hoc
• rarely occurring configuation in which every node is connected to every other node 
• usually only occurs in wireless networks in "ad hoc" mode 
• each wireless card maintains a connection to ech other wireless node it wish to connect with 
• is inefficient and requires a large amount of overhead and is difficult to manage
5. Combined/Hybrid 
• a topology referring to the case where more than one topology is utilized 

Types of networks(Access Models)

1. Decentralized
• often referred to as "peer to peer" network 
• does not contain any distinctions between client and server 
• every node acts as a client and/or server depending on the task at hand
• difficult to maintain (each node must be manually configured, updated, maintained individually)
2. Client-Server Access
• nodes can either act as "clients' or as "servers" 
• management is easy
• network can offer services that decentralized networks cannot 
3. Centralized
• a modified client-server network in which clients have no individual control 
• all maintenance and setup occurs at the server level 

Network+ Review

1. What type of fiber commonly uses lasers as a transmission source?
• Single-Mode Fiber  is used for laser trasmission
• Multi-Mode Fiber is used for LED most commonly 
• large-core fiber is another name to multi-mode fiber 
2. Is distance the only advantage in using single-mode over multi-mode fiber-optic cable?
• Multi-Mode Fiber
• short range communication (up to 2 km) 
• does not use lasers, most commonly uses LED 
• inexpensive light source 
• uses an orange color cable 
• called multi-mode because light can take more than one path through the cable 
• single-mode fiber
• small core 
• light only takes one path 
• up to 100km without processing
• most commonly uses laser light 
• normally a yellow cable color
• Short Answer, YES.
3. What is the difference between a logical and a physical network topologies?

• Completely different forms of documenting a network
• physical network layout
• 
• shows routers, servers, other connections 
• main issue is determining what subnet things are on 
• devices in a physical map can be on completely different networks 
• used for troubleshooting physical issues (i.e. cabling and conections)
• Logical network diagram 
• 
• you can see the routing paths 
• used for troubleshooting data connections
• given subnets 
• identifies location routers 

Media Converters

Media Converters 

• used to convert from one form of media to another
• most typical is to convert between copper cabling and fiber optic cabling 

CSU/DSU

• Channel Service Unit/Data Service Unit 
• a hardware device which converts data frames used on a LAN into data frames uesd on a WAN
• typically used to connect a T1 line to a local network

Network+

Load Balancer

• Load balancers are used when there are more than one line of communication available
• help to divide communication evenly between the different communication lines
• a form of clustering
• where you have more than one server servicing clients 

Bandwidth Shaper 

• used to help make communication more efficient
• provide a much higer level of control over what data gets sent where and when 
• can limit what data gets sent at what time 
• also known as bandwidth throttling 

Understanding IPv6 routing

Understanding Why IPv6 was Created 

• Limitations of IPv4
• IPv4 has been in use since 1981
• introduced and detailed in RFC 791 
• no substantial updates/improvements
• Exhaustion of IPv4 Address Space
• Explosive growth of the commercial internet
• proliferation of IP-enables devices (smartphones, tablets, etc)
• short-term solutions
• CIDR Classless Interdomain Routing
• NAT Network Address Translation 
• Private Addressing
• Integrated Security
• Original IPv4 specification did not indentify any security mechanisms
• IPsec was a later addition to IP 
• Scalability
• even with CIDR a typical BGP routing table is enormous 
• AT&T route server lists around 373,800 prefixes
• governments are mandating IPv6 adoption
• Benefits of IPv6 Improvements
• Vast Address Space
• 128 bit addressing (as opposed to 32 bit)
• addressing space is about 340 trillion addresses
• Address Assignment
• ability of a device to detect/create its own address
• advanced DHCP and auto-configuration features 
• Global Address Aggregation
• Hierarchical structure

Troubleshooting OSPF: Show Commands and Debug Commands

Relevant Debug and Show Commands 

1. OSPF Show Commands
2. OSPF Debug Commands 

OSPF Show Commands

• Show IP Protocols 
• Data Displayed by the command:
• OSPF Status and process-id
• area types configured
• protocols being redistributed
• networks being advertised
• neighbors/gateways
• helpful in troubleshooting:
• neighbor relationships
• missing routes
• summarization issues 
• filtering problems 
• Show IP route OSPF
• Data Displayed by the Command;
• OSPF routes from neigbors
• administrative distance
• cumulative cost metric
• route source/interface
• helpful in troubleshooting:
• missing routes 
• summarization issues 
• filtering problems
• general troubleshooting 
• Show IP OSPF Interfaces
• Data Displayed:
• Interfaces participating in OSPF
• Network Type(s)
• Neighbor count
• Authentication Type
• Timer Values
• Helpful in troubleshooting:
• neighbor relationships
• local congiuration issues
• routing problems
• Show IP OSPF Neighbors
• data displayed:
• Active fully adjacent neighbors
• router ID of neighbors
• IP address/interface of neighbors
• dead time of neighbors
• neighbor state/DR state (designated router state)
• Helpful for;
• Neighbor relationships
• local configuration issues
• Show IP OSPF Database
• Data Displayed:
• LSA types Per area
• Advertising router
• Link ID(Subnet)
• age
• Helpful For:
• Missing Routes
• Filtering Problems
• General troubleshooting