Objective 1 Network Architecture Flashcards
Router
Any piece of hardware or software that forwards packets based on their destination IP address. Routers work at the Network layer of the OSI and at the Internet layer of the TCP/IP model
Switch
looks like a hub because all nodes plug into it, but they take advantage of MAC addresses, effectively creating point-to-point connections between two conversing computers.
Multilayer switch
A Layer 3 switch forwards traffic based on IP and is a router that does what a traditional router does in software… in hardware and is by definition a multilayer switch
Firewall
Devices or software that protect an internal network from unauthorized access by acting as a filter.
IDS
Intrusion Detection System - an application that inspects packets, looking for active intrusions. an IDS functions inside the network.
IPS
Intrusion Protection System - sits directly in the flow of network traffic. An IPS can stop an attack while it is happening, network bandwidth and latency take a hit, and if IPS goes down, the link might go down too.
Access Point (Wireless/wired)
A device designed to interconnect wireless network notes with wired networks. A basic WAP operates like a hub and works at OSI layer 1.
Content Filter
AKA Content Switch - works at layer 7 of the OSI. They work with web servers and are able to read the incoming HTTP and HTTPS requests. This allows advanced actions like handling SSL certificates and cookies removing the workload from the web servers.
Load balander
Making a bunch of servers look like a single server, creating a server cluster.
Hub
A central box in early days of networking. When it receives a frame, it makes an exact copy of that frame sending a copy of the original frame to every other system on the network.
Analog modem
Old-style analog-to-digital devices. Modulator converts digital to analog. A demodulator converts analog to digital. Device that does both is a modem.
Packet Shaper
A traffic shaping devices that controls the flow based on packet rules.
VPN Concentrator
A VPN-capable router. Layer 2 Tunneling Protocol (L2TP) and PPTP and Layer 2 Forwarding (L2F) and added support to run on almost any type of connection possible.
VPN
Virtual Private Network encrypted tunnels between a computer or a remote network and a private network through the internet.
site to site/host to site/host to host
site-to-site - enables two separate LANS to function as a single network, sharing files and services as if in the same building.
Host-to-site - connect a single faraway PC to cisco VPN
host-to-host - a specific single connection between two machines using VPN software or hardware.
Protocols
An agreement that governs the procedure used to exchange information between cooperating entities; usually includes how much information is to be sent, how often it is sent, how to recover from transmission errors, and who is to receive the information.
IPSec
Internet Protocol Security - an authentication and encryption protocol suite that works at the internet/network layer and should become the dominant authentication and encryption protocol suite as IPv6 continues to roll out.
GRE
Generic Routing Encapsulation - used to make point-to-point tunnel connection that carries all sorts of traffic over Layer 3, including multicast and IPv6 traffic.
SSL VPN
Secure Socket layer VPN. Does not require any special client software. Clients connect to the VPN server using a standard Web browser with the traffic secured using SSL.
PTP/PPTP
Point-to-Point Tunneling Protocol - an advanced version of PPP that queries for an IP address and creates a secure tunnel through the internet back to the Private LAN.
TACACS/RADIUS
Terminal Access Controller Access Control System was developed by Cisco to support AAA in a network with many routers and switches. Uses TCP port 49 by default, separates authorization, authentication and accounting into different parts. Uses PAP, CHAP and MD5 hashes as well as Kerberos.
Remote Authentication Dial-In User Service is the better know AAA standard and was created to support ISPs with thousands of modems in hundreds of computers to connect to a single central database.
RAS
A server running the Routing and Remote Access Service dedicated to handling users who are not directly connected to a LAN but who need to access file and print services on the LAN from a remote location.
Web services
Applications and processes that ban be accessed over a network, rather than being accessed locally on the client machine. Web services include things such as web-based e-mail,k network-shareable documents, spreadsheets, and databases, and many other types of cloud-based applications.
Unified voice services
Complete, self-contained internet services that rely on nothing more than software installed on computers and the computers’ microphone/speakers to provide voice telecommunication over the internet. All of the interconnections to PSTN are handled in the cloud.
Network controllers
a program that can dictate how both physical and virtual network components move traffic through the network.
DHCP
Dynamic Host Configuration Protocol - automatically assigns an IP address whenever a computer connects to the network.
Static vs dynamic IP addressing
typing all the information in (static addressing) or by having a server program running on a system that automatically passes out all IP information as they boot up (dynamic addressing)
Reservations
Setting DHCP sever to reserve addresses for specific machines
Scopes
A range of IP addresses configured on DHCP server to pass out as needed
Leases
A fixed amount of time, generally 5-8 days, that a DHCP server assigns IP information to a machine. Near the end of the lease time, the server looks at the MAC address information and unless another computer has taken the lases, give the DHCP client the same IP information.
Options (DNS servers, suffixes)
A special option to the DHCP server, called the DNS suffix, it helps the clients access network resources more efficiently
IP helper/DHCP relay
DNS servers that redirect your browser to advertising when you type in an incorrect URL
DNS
Domain Name System - a name resolution protocol that supports name resolution on time in-house networks as well as the entire internet.
DNS Servers
Top-level domain servers (com, org, etc) that delegate to thousands of second-level DNS servers (totalsem.com, whitehouse.gov).
DNS Records (A, MX, AAAA, CNAME, PTR)
A records are the IPv4 addresses and names of all the systems on the totalhome domain.
MX Records are used exclusively by SMTP server to determine where to send mail.
(CNAME) A Canonical Name record acts like an alias
AAAA records are for IPv6 IP addressing
PTR pointer record created for a reverse lookup zone
Dynamic DNS
(DDNS) Enables DNS servers to get automatic updates of IP addresses of computers in their forward lookup zones, mainly by talking to the local DHCP server.
Proxy, Reverse Proxy
Proxy Server sits between clients and external servers, pocketing the requests from the clients for server resources and making those requests itself. The client computes never touch the outside servers and thus stay protected from any unwanted activity.
Reverse Proxy acts on behalf of its servers. Clients contact the revers proxy server, which gathers information from its associated servers and hands that information to the clients.
NAT
Network Address Translation - hides the IP addresses of computers on the LAN but still enable those computers to communicate with the broader internet.
PAT
most common form of NAT that handles one-to many connections - uses port number to map traffic from specific machine in the network.
SNAT
Static NAT maps a single routable IP address to a single machine, enabling you to access that machine from outside the network.
DNAT
Dynamic NAT - many computers can share a pool of routable IP addresses that number fewer than the computers.
Port Forwarding
you can designate a specific local address for various network services.
Fiber characteristics and benefits for WAN
A high-speed physical medium for transmitting data that uses light rather than electricity to transmit data and is made of high-purity glass fibers sealed within a flexible opaque tube. Much faster than conventional copper wire.
SONET
Synchronous Optical Network - international standard introduced in 1987, all primary fiber-optic carriers dropped their own standards and moved to a new international standard.
DWDM
Dense wavelength division multiplexing - enabled an individual single-mode fiber to carry multiple signals by giving each signal a different wavelength by using different colors of laser lights.
CWDM
Coarse wavelength division multiplexing - also relies on multiple wavelengths of light to carry a fast signal over long distances. It’s simpler than DWDM, which limits its practical distance to 60 KM
Frame relay
Works at layer 2 of the OSI model, using frames rather than packets. It switches frames quickly but without any guarantee of data integrity at all. It will discard frames whenever there is network connections, it is up to higher level protocols to error-check as needed.
Satellite
Access comes in two types: one-way and two-way. One-way means you download via satellite but us PSTN/dial-up to upload. Two-way means satellite service handles both.
Broadband cable
Cable modes have phenomenal top speeds. The cable modem connects to an outlet via coaxial cable. It’s the same cable line, just split from the main line.
DSL/ADSL
Digital subscriber Line, a fully digital, dedicated connection. It uses PSTN. They are either symmetric DSL or asymmetric DSL.
ISDN
Integrated Services Digital Network. Sending telephone transmission across fully digital lines end-to-end. B (bearer) Channels carry data and voice information using standard DSo channels (64 Kbps). D (delta) Channels carry setup and configuration information at 16 Kbps.
ATM
Asynchronous Transfer Mode - a network technology originally designed for high-speed LANs. It integrated voice, video and data on one connection, using short and fixed-length frames called cells to transfer information. Works at Layer 2 of OSI, it is also a packet-switching technology.
PPP/Multilink PPP
Point-to-Point Protocol enabled two point-to-point devices to connect, authenticate with a user name and password, and negotiate the network protocol the two devices will use. Multilink PPP is a protocol using more than one modem at the same time with link aggregation to increase speed.
MPLS
Multiprotocol Label Switching is an improved technology that is a replacement for frame relay and ATM switching. It sits between Layer 2 header and the Layer 3 information.
GMS/CDMA
Global System for Mobile is the first group of networking technologies widely applied to mobile devices. It enabled multiple users to share a single channel by splitting the channel into time slices. Code Division Multiple Access came out shortly after but uses a spread-spectrum form of transmission that is not compatible with GSM. It changes the frequencies used by each user.
LTE/4G
Long Term Evolution - offers voice and data and coexisits just fine with slower technologies. It can readily replace wired network technology by connecting to hotspots.
HSPA+
Evolved High-Speed Packet Access. The final 3G standard and the one true 3G technology, providing theoretical speeds up to 168 Mbps, although in reality, rarely passed 10 Mbps.
3G
a technology that supported IMT-2000 standard to address a number of shortcomings in mobile technology.
Edge
Enhanced Data rates for GSM Evolution offering speeds up to 384 Kbps. One of the last GSM standards released.
Dial-up
Oldest and least expensive method to connect to the internet.
WiMAX
Early speeds running around 30 Mbps, provided the ideal of wireless metropolitan area networks, where cities could simply roll out fast internet access to citizens at a fraction of the cost of physical connections.
Metro-Ethernet
Ethernet throughout a city.
Leased lines
A leased line is a private bidirectional or symmetric telecommunications circuit between two or more locations provided in exchange for a monthly rent. Sometimes known as a private circuit or data line in the UK. … Typically, leased lines are used by businesses to connect geographically distant offices.
T-1
24 Channels 1.544 Mbps. A dedicated phone connection that you lease, usually on a monthly basis, from the telephone company. It has no telephone number and it’s always connected.
T-3
672 Channels- 44.736 Mbps. Supports a data rate of about 45 Mbps on a dedicated telephone connection. It consists of 672 individual DSo channels and are mainly used by regional telephone companies and ISPs connecting to the internet.
E-1
32 Channels 2.048 Mbps. The European format for digital transmission carries signals at 2.048 Mbps.
E-3
512 Channels 34.368 Mbps. Carry 16 E1 lines with a bandwidth of about 34 Mbps.
OC3
Optical Carrier standard denotes the optical data carrying capacity of fiber-optics. OC-3 is 155.52 Mbps
OC12
Optical Carrier standard denotes the optical data carrying capacity of fiber-optics. OC-12 is 622.08 Mbps.
Circuit switch vs packet switch
DPacket-switched networks move data in separate, small blocks - packets - based on the destination address in each packet. When received, packets are reassembled in the proper sequence to make up the message. Circuit-switched networks require dedicated point-to-point connections during calls.
Copper Connectors
The most common form of cabling - general term to lump all types of cabling together
RJ-11
Telephones use RJ-11 connectors, designed to support up to two pairs of wires.
Rj-45
Networks use the four-pair RJ-45 connectors
Rj-48C
The shielded, two-pair cabling that connects the two ends of a T1 connection. Two wires are for sending data and two wires are for receiving data. The cable ends with a modular jack called an RJ-48C that look a lot like the RJ-45.
DB-9/RS-232
Classic serial port. Recommended Standard
DB-25
Parallel port limited to point-to-point topology using 25-pin female.
UTP Coupler
small devices with two female ports that enable you to connect two pieces of cable together to overcome distance limitations. UTP couplers are most common.
BNC Coupler
small devices with two female ports that enable you to connect two pieces of cable together to overcome distance limitations.
F-connector
Same type used to connect televisions to cable boxes or to satellite receivers. It screws on, making for a secure connection.
110 block
Most common patch panel used today. It has small metal-lined grooves for the individual wires. The punchdown tool has a blunt end that forces the wire into the groove. Them metal in the groove slices the cladding enough to make contact.
66 block
OLder punchdown block patch panel, found in just about every commercial telephone installation. It’s still common to find 66-block patch panels in a telecommunications room.
Copper cables
The most common form of cabling uses copper wire wrapped up in some kind of protective sheathing.
568A grouping is WO-G-WG-B-WB-O-WB-B
568B grouping is WO-O-WG-B-WB-G-WB-B
Shielded vs unshielded
Most common type of cabling used in networks consists of twisted pairs of cables bundled together into a common jacket. Shielded twisted pair, consists of twisted pairs of wires surrounded by shielding to protect them from EMI. STP is pretty rare primarily because there is little need for the shielding. It only really matters in locations with excessive electronic noise.
CAT3, CAT5, CAT5e, CAT6, CAT6a
CAT (category ratings) are officiall rated in MHz. The most common are:
CAT3 - 16 MHz, 16 Mbps
CAT5 - 100 MHz, 100 Mbps no longer recognized
CAT5e - 100 MHz, 1000 Mbps
CAT6 - 250 MHz, 10000 Mbps
CAT6a - 500 MHz, 10000 Mbps
PVC vs Plenum
Fire ratings - PVC has no significant fire protection. Plenum-rated cables create much less smoke and fumes. Most city ordinances require the use of plenum cable for network installations.
RG-59
Coaxial cable primarily used for cable television rather than networking. Cable modems connect to it
RG-6
Digital cable that replaced RG-59 for networking. Both RG-6 and RG-59 are rated at 75 Ohms.Cable modems connect to it.
Straight-through cable
Uses the same stardard for the RJ-45 on both ends. Uplink ports enable you to connect two hubs using a straight-through cable. Port is clearly marked on the hub and allows you to daisy-chain them. For more than two, use one uplink port and one regular port.
Crossover Cable
Uses 568A on one end and 568B on the other. A special twisted pair. A crossover cable reverses the sending and receiving pairs on one end of the cable. With the sending and receiving pairs reversed, the hubs can hear each other. A standard cable will attempt to send data on the second pair of wires (3 and 6) and will listen for data on the first pair (1 and 2).
Rollover Cable
Has an RJ-45 on one end and a class RS-232 serial port on the other. They’re used to connect a laptop or other computer directly to a Cisco switch or router.
Fiber connectors
ST, SC, LC are the most common types of fiber connectors
ST
Stick and twist - fiber connector type
SC
Stick and click - fiber connector type
LC
Little Connector - fiber connector type
MTRJ
Mechanical Transfer Registered Jack - connector type that gained popularity with companies like Cisco and is still very common.
FC
A type of fiber connector that you screw into place, eliminating problems with high vibration environments.
Fiber cables
Two varieties of fiber-optic cables. Most common size is 62.5/125um. one fiber is used for sending and the other for receiving - often connected together like a lamp cord. A
Single-Mode Fiber
A fiber optic cable that uses lasers is known as a single-mode fiber.
Multimode Fiber
A fiber-optic cable that uses LEDs is known as multimode fiber. Multimode fiber has modal distortion - signals sent at the same time don’t arrive at the same time because the paths differ slightly in length.
Fiber Coupler
a small device with two female ports that enable you to connect two pieces of cable together to overcome distance limitations
APC vs UPC
Angled Physical Contact vs Ultra Physical Contact. Angled connectors add an 8-degree angle to the curved end lowering signal loss further plus their connection does not degrade from multiple insertions. Ultra connectors are polished extensively for a superior finish to reduce signal loss significantly over PC connectors.
Media Converter
Used to connect any type of Ethernet cabling together. Most are plain-looking boxes with a port or dongle on either side.
Single mode fiber to Ethernet
A media converter that takes single mode fiber to Ethernet. SMF to UTP/STP
Multimode fiber to Ethernet
A media converter that takes multimode fiber to Ethernet. MMF to UTP/STP
Fiber to coaxial
A media converter that takes fiber to Ethernet. SMF to coaxial cable
Single mode to multimode
a media converter that takes single mode fiber to multimode fiber. SMF to MMF
