Concepts Flashcards
3 categories of network components
Devices: hardware such as PCs, routers, switches.
Media: cabling or wireless
Services: Includes applications such as email as well as the processes that directs and move messages through the network.
4 types of Home & Small office internet connections
Cable - Typically offered by cable television service providers, the Internet data signal is carried on the same cable that delivers cable television.
DSL - Digital Subscriber Lines runs over a telephone line. In general, small office and home office users connect using Asymmetrical DSL (ADSL), which means that the download speed is faster than the upload speed
Cellular - Cellular Internet access uses a cell phone network to connect.
Satellite - Satellite dishes require a clear line of sight to the satellite.
Dial-up Telephone - An inexpensive option that uses any phone line and a modem. The low bandwidth provided by a dial-up modem connection is usually not sufficient for large data transfer, although it is useful for mobile access while traveling.
4 types of Business Internet Connections
Dedicated Leased Line - Leased lines are actually reserved circuits within the service provider’s network that connect geographically separated offices for private voice and/or data networking
Ethernet WAN - Ethernet WANs extend LAN access technology into the WAN.
DSL - Business DSL is available in various formats. A popular choice is Symmetric Digital Subscriber Lines (SDSL) which is similar to the consumer version of DSL, but provides uploads and downloads at the same speeds
Satellite - Similar to small office and home office users, satellite service can provide a connection when a wired solution is not available
4 characteristics the network infrastructure needs to address
Fault tolerance - A fault tolerant network is one that limits the impact of a failure by having multiple paths to a destination (redundancy)
Scalability - A scalable network can expand quickly.
QoS - Managed by the router; ensures priority for certain traffic.
Security - Includes physical securing of devices that provide network connectivity and preventing unauthorized access to the software that resides on them.
3 primary requirements of information security
Confidentiality - Only the intended and authorized recipients can access and read data.
Integrity - Having the assurance that the information hasn’t been altered in transmission from origin to destination.
Availability - Have the assurance of timely and reliable access to data services.
4 types of cloud computing
Public clouds - Uses the internet to provide services made available to the general population on a pay-per-use model or for free.
Private clouds - Services offered in this type of cloud are specific to an organization
Hybrid clouds - Made up of two or more clouds where each part remains distinctive objects but both are connected using a single architecture.
Custom clouds - Built to meet the needs of a specific industry such as healthcare or media.
7 types of security threats
Viruses, worms and trojan horses - Malicious software running on a user device.
Spy/adware - Secretly collects information about the user.
Zero-Day Attacks - Occurs on the first day a vulnerability becomes known.
Hacker attacks - An attack by a knowledgeable user.
Denial of Service - Attacks designed to slow or crash a network.
Data interception and theft - An attack to capture private information from an organization’s network.
Identity Theft - Steal login credentials of a user.
Types of security solutions
Security components for a SOHO: antivirus, antispyware and firewall filtering.
In addition to the above, network security components for a corporate network should include: Dedicated firewall, ACL, IPS, VPN.
3 Types of access methods
Console - out-of-band access
SSH - Secure method
Telnet - Insecure method; user authentication, passwords and commands are sent in plaintext.
Limiting Device Access
Secure privileged EXEC access with a password.
Secure user EXEC access with a password.
Secure remote Telnet access with a password.
Encrypt all passwords.
Provide legal notification.
Hostname Requirements
Start with a letter
Contain no spaces
End with a letter or digit
Be less than 64 characters in length
Password guidelines
Greater than 8 characters
Combination of upper and lowercase letters, numbers, special characters and/or numeric sequences.
Avoid using the same password for all devices.
Don’t use common words.
3 Communication Fundamentals
Source.
Destination.
The channel or media the message travels over.
5 Protocol requirements
Message encoding Message formatting and encapsulation Message size Message timing Message delivery options
2 Primary functions of ethernet
Communication over a data link.
The physical transmission of data on the network media.
3 functions of the physical layer
Physical components
Encoding
Signaling
6 Frame fields
Preamble(7 bytes) & Start Frame Delimiter (SFD) (1 byte): Provides synchronization. Tells the receiver to get ready to receive a new frame.
Destination MAC: 6 byte. Can be uni, multi or broadcast.
Source MAC address: 6 byte. Must be unicast.
EtherType:2 bytes. Identifies the layer 3 protocol in the data field. 0x800 for IPv4, 0x86DD for IPv6, 0x806 for ARP.
Data: 46-1500 bytes. Commonly an IPv4 packet. All frames must be at least 64 bytes long.
FCS: 4 bytes. Uses CRC for error detection. Included after the data to form the trailer.
3 primary functions of data encapsulation
Frame delimiting - These delimiting bits provide synchronization between the transmitting and receiving nodes.
Addressing – Encapsulation provides for data link layer addressing
Error detection – Each frame contains a trailer used to detect errors in transmission.
Primary function of Media Access Control
Media access control is responsible for the placement and removal of frames from the media. This ethernet sublayer communicates directly with the physical layer.
Media Access Control Methods
Contention-based: All nodes operating in half-duplex will compete for the use of the medium but only one device can send at a time.
Controlled Access: Each node has its own time to use the medium.(inefficient)
