CompTIA Network+ N10-006 - 1.4 Flashcards
Synchronous optical networking (SONET)
• Multiplex digital signals over optical cable
– All circuits are synchronized to an atomic clock
• SONET
– Synchronous Optical NETworking
– American National Standards Institute (ANSI) standard
– Used in United States and Canada
• SDH
– Synchronous Digital Hierarchy
–International Telecommunications Union (ITU) Standard
– Used everywhere else
• Both are effectively identical
SONET/SDH speeds
- SONET / Synchronous Transport Signals (STS)
* SDH / Synchronous Transport Modules (STM)
Wavelength-Division Multiplexing (WDM)
• Wavelength-Division Multiplexing
– end multiple carriers over a single fiber
• Use different wavelengths for each carrier
– Different “colors”
• CWDM (Coarse Wavelength-Division Multiplexing)
– 10BASE-LX4 uses four 3.125 Gbps/sec carriers at four different wavelengths
• DWDM (Dense Wavelength-Division Multiplexing)
– Multiplex multiple OC carriers into a single fiber
– Add 160 signals, increase to 1.6 Tbit/s
ATM
• Asynchronous Transfer Mode
– A common protocol transported over SONET
• 53-byte “cells” spaced evenly apart
– 480byte for data, 5 byte routing header
• High throughput, real-time, low latency
– Data, voice, and video
• Max speeds of OC-192
– Limits based on segmentation and reassembly (SAR)
Frame relay
• One of the first cost0effective WAN types
– Departure from circuit-switches T1s
• LAN traffic is encapsulated into frame relay frames
• Frames are passed into the “cloud”
– Magically pop out the other side
- Usually 64 Kbits/s through DS3 speeds
- Replaced by MPLS (Multiprotocol Label Switching)
Multiprotocol Label Switching
• Learning from ATM and Frame Relay
–Keep the advantages, ditch the disadvantages
• Packets through the WAN have a label
– Routing decisions are easy
• Any transport medium, any protocol inside
–IP packets, ATM cells, Ethernet frames
–OSI layer 2.5 (!)
• Increasingly command WAN technology
–Ready-to-network
MPLS pushing and popping
- Labels are “pushed” onto packets as they enter the MPLS cloud
- Labels are “popped” off on the way out
Satellite networking
• Communication to a satellite
–Non-terrestrial communication
• High cost relative to terrestrial networking
–15 Mbit/s down, 2 Mbit/s up
– Remote sites, difficult-to-network sites
• High latency
– 250 ms up, 250 ms down
• High frequencies - 2 GHz
– Suffer from line of sight, rain fade
ISDN (Integrated Services Digital Network)
• BRI - Basic Rate Interface (2B+D)
– Two 64 kbit/s bearer (B) channels
– One 16 kbit/s signaling (D) channel
• PRI – Primary Rate Interface
–Delivered over a T1 or E1
• T1 –23B + D
• E1 – 30B + D + alarm channel
–Commonly used as a connectivity from the PSTN to large phone systems (PBX)
DSL (Digital Subscriber Line)
• ADSL (Asymmetric Digital Subscriber Line)
– Uses telephone lines
– Download speed is faster than the upload speed (asymmetric)
–~10,000 foot limitation from the central office
–24 Mbit/s downstream / 3.3 Mbit/s upstream
VDSL (Very-high-bit-rate DSL)
– 3 Mbit/s through 100 Mbit/s
PPPoE (Point to Point Protocol over Ethernet)
• Encapsulate point-to-point protocol over Ethernet
– The past with the present
• Common on DSL networks
– Telephone providers know PPP
• Easy to implement
– Support in most operating systems
– no routing required
– Similar to existing dialup architecture
•Allows competition
–Once connected, data is switched to the appropriate ISP
Cable modem
• Data on the “cable” network
– DOCSIS (Data Over Cable Service Interface Specification)
• High-speed networking
–4 Mbit/s through 250 Mbits/s
• Múltiple services
–Data, voice
Dialup
• Network with voice telephone lines
–Analog lines with limited frequency response
• 56 kbit/s modems
–Compression up to 320 kbit/s
• Relatively slow throughput
–Difficult to scale
• Legacy systems, network utility
–May be difficult to find a modem
Point-to-point protocol
• Create a network connection between two devices
–OSI layer 2 / data link protocol
–Communicate using many different protocols
• Works almost anywhere
– Dial-up connections, serial links, mobile phone, DSL (PPPoE)
• Provides additional data link functionality – Authentication – Compression –Error detection –Multilink
Multilink PPP
• Aggregate traffic across multiple point-to-point links
–Why use a single connection when you can use two?
• Scale up your throughput
–Use multiple links simultaneously
–Requires additional hardware and network
• MPPP adds numbers to the data fragments
–Fixes out-of-order frames
Cellular networks
• Mobile devices
–”Cell” phones
•Separate land into “cells”
–Antenna coverages a cell with certain frequencies
• 2G networks
–GSM - Global System for Mobile Communications
–CDMA - Code Division Multiple Access
• Poor data support
–Originally uses circuit-switching
–Minor upgrades for some packet-switching
LTE (Long Term Evolution) and HSPA+
• Long Term Evolution (LTE)
–Based on GSM/EDGE
– Download rates of 300 Mbit/s, upload 75 Mbit/s
– A “4G” technology
• Evolved High Speed Packet Access (HSPA+)
– Based on CDMA
–Download rates of 84 Mbit/s, upload 22 Mbit/s
•The 3rd Generation Partnership Project (3GPP)
–Collaboration between telecommunications organizations
WiMAX (Worldwide Interoperability for Microwave Access)
• WiMAX (Worldwide Interoperability for Microwave Access)
– Wireless high-speed Internet access
• 30 mile signal radius
–”Wi-Fi on steroids”
• Fixed WiMAX
–IEEE 802.16
–37 Mbit/s download, 17 Mbit/s upload
•Mobile WiMAX
–IEEE 802.16e-2005
–Theoretical throughput of 1 Gbit/s for fixed stations
– Mobile station throughput of 100 Mbit/s (“4G”)
T1 / E1
•T-Carrier Level 1
–Time-division multiplexing
–North America, Japan, South Korea
–24 channels
•64 kbit/s per channel
• 1.544 Mbit/s line rate
• E-Carrier Level 1
–E is for Europe
•32 channels
• 64 kbit/s per channel
• 2.048 Mbit/s line rate
T3 / DS3 / E3
• T-Carrier Level 3
–Delivered on cox (BNC connectors)
–DS3 is the data carried on a T3
• T3
–Twenty-eight T1 circuits
–44.736 Mbit/s
• E3
–Sixteen E1 circuits
– 34.368 Mbit/s
Circuit switching
• Circuit is established between endpoints before data passes
– Like a phone call
• Nobody else can use the circuit when it’s idle
–Inefficient use of resources
• Connect is always there
– It’s mine, You can’t use it.
Circuit switching
- POT (plain old telephone server) and PSTN (public switched telephone network)
- T1 / E1 / T3 / E3
- ISDN
Packet switching
• Data is grouped into packets
–Voice, data , video, etc.
–Like a network
• The media is usually shared
–Someone else can use it, even when you don’t.
• One connection may have more bandwidth allocated than another
–How much money would you like to spend?
- SONET, ATM
- DSL
- Frame relay
- MPLS
- Cable modem
- Satellite
- Wireless
RJ11 connector
• 6 position, 2 conductor (6P2C)
–RJ14 uses 6P4C for dual-line use
• Telephone connection
RJ45 connector
• 8 position, 8 conductor (8P8C)
–Modular connector
•Similar in shape to an RJ48C
–8P4C, used in T1/WAN data lines
DB-9 (RS-232)
• Recommended standard 232
– An industry standard since 1969
• Serial communications standard
–Built for modem communication
• Used for modems, printers, mice, networking
Couplers
•Connect cables together
– Lengthen the cable run
• Very specific use cases
– Signal loss for each coupler
•Useful for temporary or one-time use
–Permanent links are generally home runs
BNC connector
•Bayonet Neil-Concelman
–Paul Neil (Bell Labs) and Carl Concelman (Amphenol)
•Coaxial cable connector
– RG-58 used in 10BASE2, DS3 WAN links
• Rigid and bulky
–Can be difficult to work with
F-connector
• Cable television
– Cable modem
• RG-6
– Threaded connector
66 block
• A patch panel for analog voice
– And some digital links
• Left Sid is patched to the right
–Easy to follow the path
• Wire and a punch-down tool
–No additional connectors required
110 block
• Wire-to-wire patch panel
– No intermediate interface required
• Replaces the 66 block
–Patch category 5 and Category 6 cables
•Wires are “punched” into the block
– Connecting block is on top
•Additional wires punched into connecting block
– Patch the top to the bottom
