Networking Flashcards
1
Q
What does TCP/IP stand for?
A
Transmission Control Protocol/Internet Protocol
2
Q
What is TCP?
A
Transmission Control Protocol
Connection-oriented
– A formal connection setup and close
- “Reliable” delivery
– Recovery from errors
– Can manage out-of-order messages or retransmissions - Flow control
– The receiver can manage how much data is sent
3
Q
What is UDP?
A
User Datagram Protocol
* Connectionless - No formal open/close to the connection
- “Unreliable” delivery
– No error recovery
– No reordering of data or retransmissions - No flow control
– Sender determines the amount of data transmitted
4
Q
When would you use UDP?
A
Real-time communication
– There’s no way to stop and resend the data
– Time doesn’t stop for your network
Connectionless protocols
– DHCP (Dynamic Host Configuration Protocol)
– TFTP (Trivial File Transfer Protocol)
5
Q
What does DHCP stand for?
A
Dynamic Host Configuration Protocol
6
Q
What does TFTP stand for?
A
TFTP (Trivial File Transfer Protocol)
7
Q
When would you use TCP? (and with what?)
A
- Connection-oriented protocols prefer a “return receipt”
– HTTPS (Hypertext Transfer Protocol Secure)
– SSH (Secure Shell) - The application doesn’t worry about out of order
frames or missing data
– TCP handles all of the communication overhead
– The application has one job
8
Q
What are Non-ephemeral ports ?
A
permanent port numbers
– Ports 0 through 1,023
– Usually on a server or service
9
Q
What are ephemeral ports ?
A
- Ephemeral ports – temporary port numbers
– Ports 1,024 through 65,535
– Determined in real-time by the client
10
Q
Port numbers range
A
TCP and UDP ports can be any number between
0 and 65,535
* Most servers (services) use non-ephemeral
(not-temporary) port numbers
– This isn’t always the case
– It’s just a number.
11
Q
T or F – TCP port numbers aren’t the same as UDP port number
A
T
12
Q
T or F - TCP and UDP are encapsulated within IP.
A
T
13
Q
What is SSH?
A
SSH - Secure Shell
* Encrypted communication link in terminal communication between systems
14
Q
What are Routers?
A
Routes traffic between IP subnets
– Makes forwarding decisions based on IP address
– Routers inside of switches sometimes called
“layer 3 switches”
* Often connects diverse network types
– LAN, WAN, copper, fiber
15
Q
What are Switches?
A
- Bridging done in hardware
– Application-specific integrated circuit (ASIC)
– Forwards traffic based on data link address - Many ports and features
– The core of an enterprise network
– May provide Power over Ethernet (PoE) - Multilayer switch
– Includes routing functionality
16
Q
What are Unmanaged Switches?
A
- Very few configuration options
– Plug and play - Fixed configuration
– No VLANs - Very little integration with other devices
– No management protocols - Low price point
– Simple is less expensive
17
Q
What are managed Switches?
A
- VLAN support
– Interconnect with other switches via 802.1Q - Traffic prioritization
– Voice traffic gets a higher priority - Redundancy support
– Spanning Tree Protocol (STP) - Port mirroring
– Capture packets - External management
– Simple Network Management Protocol (SNMP)
18
Q
What are Access points?
A
Not a wireless router
– A wireless router is a router and an access point
in a single device
* An access point is a bridge
– Extends the wired network onto the wireless network
– Makes forwarding decisions based on MAC address
19
Q
What are Patch Panels?
A
Combination of punch-down blocks and
RJ-45 connectors
* Runs from desks are made once
– Permanently punched down to patch panel
* Patch panel to switch can be easily changed
– No special tools
– Use existing cables
20
Q
What are Firewalls?
A
- Filters traffic by port number
– OSI layer 4 (TCP/UDP)
– Some firewalls can filter based on the application - Can encrypt traffic into/out of the network
– Protect your traffic between sites - Can proxy traffic
– A common security technique - Most firewalls can be layer 3 devices (routers)
– Usually sits on the ingress/egress of the network
21
Q
What is Power over Ethernet (PoE)?
A
Power provided on an Ethernet cable
– One wire for both network and electricity
– Phones, cameras, wireless access points
– Useful in difficult-to-power areas
* Power provided at the switch
– Built-in power - Endspans
– In-line power injector - Midspans
22
Q
What is PoE switch?
A
- Power over Ethernet
– Commonly marked on the switch or interfaces
23
Q
Explain PoE, PoE+, PoE++
A
- PoE: IEEE 802.3af-2003
– The original PoE specification
– Now part of the 802.3 standard
– 15.4 watts DC power, 350 mA max current - PoE+: IEEE 802.3at-2009
– Now also part of the 802.3 standard
– 25.5 watts DC power, 600 mA max current - PoE++: IEEE 802.3bt-2018
– 51 W (Type 3), 600 mA max current
– 71.3 W (Type 4), 960 mA max current
– PoE with 10GBASE-T
24
Q
Explain Hub
A
- “Multi-port repeater”
– Traffic going in one port is repeated to
every other port - Everything is half-duplex
- Becomes less efficient as network traffic increases
- 10 megabit / 100 megabit
- Difficult to find today
25
Explain Cable modem
* Broadband
– Transmission across multiple frequencies
– Different traffic types
* Data on the “cable” network
– DOCSIS (Data Over Cable Service Interface Specification)
* High-speed networking
– Speeds up to 1 Gigabit/s are available
* Multiple services
– Data, voice, video
26
Explain DSL modem
* 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 (CO)
– 52 Mbit/s downstream / 16 Mbit/s upstream are
common
– Faster speeds may be possible if closer to the CO
27
Explain ONT
Optical network terminal
– Fiber to the premises
* Connect the ISP fiber network to the copper network
– Demarcation point (demarc) in the data center
– Terminal box on the side of the building
* Line of responsibility
– One side of the box is the ISP
– Other side of the box is your network
28
Explain NIC
Network Interface Card (NIC)
* The fundamental network device
– Every device on the network has a NIC
– Computers, servers, printers, routers, switches,
phones, tablets, cameras, etc.
* Specific to the network type
– Ethernet, WAN, wireless, etc.
* Often built-in to the motherboard
– Or added as an expansion card
* Many options - Single port, multi-port, copper, fiber
29
Explain SDN
SDN (Software Defined Networking)
* Networking devices have different functional
planes of operation
– Data, control, and management planes
* Split the functions into separate logical units
– Extend the functionality and management
of a single device
– Perfectly built for the cloud
* Infrastructure layer / Data plane
– Process the network frames and packets
– Forwarding, trunking, encrypting, NAT
* Control layer / Control plane
– Manages the actions of the data plane
– Routing tables, session tables, NAT tables
– Dynamic routing protocol updates
Application layer / Management plane
– Configure and manage the device
– SSH, browser, API
30
Explain Wireless standards 802.11a
* One of the original 802.11 wireless standards
– October 1999
* Operates in the 5 GHz range
– Or other frequencies with special licensing
* 54 megabits per second (Mbit/s)
* Smaller range than 802.11b
– Higher frequency is absorbed by objects in the way
* Not commonly seen today
31
Explain Wireless standards 802.11b
* Also an original 802.11 standard - October 1999
* Operates in the 2.4 GHz range
* 11 megabits per second (Mbit/s)
* Better range than 802.11a, less absorption problems
* More frequency conflict
– Baby monitors, cordless phones,
microwave ovens, Bluetooth
* Not commonly seen today
31
Explain Wireless standards 802.11g
* An “upgrade” to 802.11b - June 2003
* Operates in the 2.4 GHz range
* 54 megabits per second (Mbit/s) - Similar to 802.11a
* Backwards-compatible with 802.11b
* Same 2.4 GHz frequency conflict problems as 802.11b
31
Explain Wireless standards 802.11n
802.11n (Wi-Fi 4)
* The update to 802.11g, 802.11b, and 802.11a
– October 2009
* Operates at 5 GHz and/or 2.4 GHz
– 40 MHz channel widths
* 600 megabits per second (Mbit/s)
– 40 MHz mode and 4 antennas
* 802.11n uses MIMO
– Multiple-input multiple-output
– Multiple transmit and receive antennas
32
Explain Wireless standards 802.11ac
802.11ac (Wi-Fi 5)
* Approved in January 2014
– Significant improvements over 802.11n
* Operates in the 5 GHz band
– Less crowded, more frequencies (up to 160 MHz
channel bandwidth)
* Increased channel bonding - Larger bandwidth usage
* Denser signaling modulation
– Faster data transfers
* Eight MU-MIMO downlink streams
– Twice as many streams as 802.11n
– Nearly 7 gigabits per second
33
Explain Wireless standards 802.11ax
802.11ax (Wi-Fi 6)
* Approved in February 2021
– The successor to 802.11ac/Wi-Fi 5
* Operates at 5 GHz and/or 2.4 GHz
– 20, 40, 80, and 160 MHz channel widths
* 1,201 megabits per second per channel
– A relatively small increase in throughput
– Eight bi-directional MU-MIMO streams
* Orthogonal frequency-division multiple access (OFDMA)
– Works similar to cellular communication
– Improves high-density installations
34
Explain RFID
RFID (Radio-frequency identification)
* It’s everywhere
– Access badges
– Inventory/Assembly line tracking
– Pet/Animal identification
– Anything that needs to be tracked
* Radar technology
– Radio energy transmitted to the tag
– RF powers the tag, ID is transmitted back
– Bidirectional communication
– Some tag formats can be active/powered
35
Explain NFC
NFC (Near field communication)
* Two-way wireless communication
– Builds on RFID, which is mostly one-way
* Payment systems
– Major credit cards, online wallets
* Bootstrap for other wireless
– NFC helps with Bluetooth pairing
* Access token, identity “card”
– Short range with encryption support
36
802.11 technologies (big picture)
* Frequency
– 2.4 GHz or 5 GHz
– And sometimes both
* Channels
– Groups of frequencies, numbered by the IEEE
– Non-overlapping channels would be ideal
* Regulations
– Most countries have regulations to
manage frequency use
– Spectrum use, power output,
interference requirements, etc.
37
bluetooth technologies (big picture)
* Remove the wires
– Headsets, speakers, keyboards / mice
* Uses the 2.4 GHz range
– Unlicensed ISM
(Industrial, Scientific and Medical) band
– Same as 802.11
* Short-range
– Most consumer devices operate
to about 10 meters
– Industrial Bluetooth devices can communicate
over 100 meters
38
what is DNS server
Domain Name System
– Convert names to IP addresses
– And vice versa
* Distributed naming system
– The load is balanced across many different servers
* Usually managed by the ISP or IT department
– A critical resource
39
what is DHCP server
DHCP server
* Dynamic Host Configuration Protocol
– Automatic IP address configuration
* Very common service
– Available on most home routers
* Enterprise DHCP will be redundant
– Usually running on central servers
40
what is File server
File server
* Centralized storage of documents,spreadsheets,
videos, pictures, and any other files
– A fileshare
* Standard system of file management
– SMB (Server Message Block),
Apple Filing Protocol (AFP), etc.
* The front-end hides the protocol
– Copy, delete, rename, etc.
41
what is Print server
Print server
* Connect a printer to the network
– Provide printing services for all network devices
* May be software in a computer
– Computer is connected to the printer
* May be built-in to the printer
– Network adapter and software
* Uses standard printing protocols
– SMB (Server Message Block), IPP (Internet
Printing Protocol), LPD (Line Printer Daemon)
42
what is Print server
Print server
* Connect a printer to the network
– Provide printing services for all network devices
* May be software in a computer
– Computer is connected to the printer
* May be built-in to the printer
– Network adapter and software
* Uses standard printing protocols
– SMB (Server Message Block), IPP (Internet
Printing Protocol), LPD (Line Printer Daemon)
43
what is Mail server
Mail server
* Store your incoming mail
– Send your outgoing mail
* Usually managed by the ISP or the IT department
– A complex set of requirements
* Usually one of the most important services
– 24 x 7 support
44
what is Syslog
Syslog
* Standard for message logging
– Diverse systems, consolidated log
* Usually a central logging receiver
– Integrated into the SIEM
* You’re going to need a lot of disk space
– No, more. More than that.
45
what is Web server
Web server
* Respond to browser requests
– Using standard web browsing protocols - HTTP/HTTPS
– Pages are built with HTML, HTML5
* Web pages are stored on the server
– Downloaded to the browser
– Static pages or built dynamically in real-time
46
what is Authentication server
* Login authentication to resources
– Centralized management
* Almost always an enterprise service
– Not required on a home network
* Usually a set of redundant servers
– Always available
– Extremely important service
47
what is Spam
* Unsolicited messages
– Email, forums, etc.
* Various content
– Commercial advertising
– Non-commercial proselytizing
– Phishing attempts
* Significant technology issue
– Security concerns, resource utilization,
storage costs, managing the spam
48
what is Spam gateways
* Unsolicited email
– Stop it at the gateway before it reaches the user
– On-site or cloud-based
49
what is All-in-one security appliance
* Next-generation firewall, Unified Threat
Management (UTM) / Web security gateway
* URL filter / Content inspection
* Malware inspection
* Spam filter
* CSU/DSU
* Router, Switch
* Firewall
* IDS/IPS
* Bandwidth shaper
* VPN endpoint
50
what is Load balancers
* Distribute the load
– Multiple servers
– Invisible to the end-user
* Large-scale implementations
– Web server farms, database farms
* Fault tolerance
– Server outages have no effect - Very fast convergence
51
what is Load balancers features
* Configurable load - Manage across servers
* TCP offload - Protocol overhead
* SSL offload - Encryption/Decryption
* Caching - Fast response
* Prioritization - QoS
* Content switching - Application-centric balancing
52
what is Proxy server
* An intermediate server
– Client makes the request to the proxy
– The proxy performs the actual request
– The proxy provides results back to the client
* Useful features
– Access control, caching, URL filtering, content scanning
53
what is SCADA / ICS
* Supervisory Control and Data Acquisition System
– Large-scale, multi-site Industrial Control Systems (ICS)
* PC manages equipment
– Power generation, refining,
manufacturing equipment
– Facilities, industrial, energy, logistics
* Distributed control systems
– Real-time information
– System control
– Requires extensive segmentation
– No access from the outside
54
what is Legacy and embedded systems
* Legacy systems
– Another expression for “really old”
– May also be “really important”
– Learning old things can be just as important as
learning the new things
* Embedded systems
– Purpose-built device
– Not usual to have direct access to
the operating system
– Alarm system, door security, time card syste
55
what is IoT (Internet of Things) devices
* Appliances
– Refrigerators
* Smart devices
– Smart speakers respond to voice commands
* Air control
– Thermostats, temperature control
* Access
– Smart doorbells
* May require a segmented network
– Limit any security breaches
56
what is IPv4 addresses
IPv4 is the primary protocol for everything we do
– You probably won’t configure anything else
* IPv6 is now part of all major operating systems
– And the backbone of our Internet infrastructure
* Internet Protocol version 4
– OSI Layer 3 address
57
what is IPv6 addresses
IPv6 addresses
* Internet Protocol v6 - 128-bit address
– 340,282,366,920,938,463,463,374,607,431,768,211,456
addresses (340 undecillion)
– 6.8 billion people could each have
5,000,000,000,000,000,000,000,000,000 addresses
58
how to Networking with IPv6 addresses
IP Address, e.g., 192.168.1.165
– Every device needs a unique IP address
* Subnet mask, e.g., 255.255.255.0
– Used by the local device to determine its subnet
– The subnet mask isn’t (usually) transmitted
across the network
* Default gateway, e.g., 192.168.1.1
– The router that allows you to communicate
outside of your local subnet
– The default gateway must be an IP address
on the local subnet
59
DNS servers w/ IP
* We remember names
– professormesser.com, google.com, youtube.com
* Internet routers don’t know names
– Routers only know IP addresses
* Something has to translate between
names and IP addresses
– Domain Name Services
* You configure two DNS servers in
your IP configuration
– That’s how important it is
60
Assigning IP Addresses DHCP
* IPv4 address configuration used to be manual
– IP address, subnet mask, gateway,
DNS servers, NTP servers, etc.
* October 1993 - The bootstrap protocol (BOOTP)
* BOOTP didn’t automatically define everything
– Some manual configurations were still required
– BOOTP also didn’t know when an
IP address might be available again
* Dynamic Host Configuration Protocol (DHCP)
– Initially released in 1997,
updated through the years
– Provides automatic address / IP configuration
for almost all devices
61
The DHCP Process (DORA)
* Step 1: Discover - Client to DHCP Server
– Find all of the available DHCP Servers
* Step 2: Offer - DHCP Server to client
– Send some IP address options to the client
* Step 3: Request - Client to DHCP Server
– Client chooses an offer and makes a formal request
* Step 4: Acknowledgment - DHCP Server to client
– DHCP server sends an acknowledgment to the client
62
Assigning IP Addresses Turning dynamic into static
* DHCP assigns an IP address from the first available from a
large pool of addresses
– Your IP address will occasionally change
* You may not want your IP address to change
– Server, printer, or personal preference
* Disable DHCP on the device
– Configure the IP address information manually
– Requires additional administration
* Better: Configure an IP reservation on the DHCP server
– Associate a specific MAC address with an IP address
63
Assigning IP Addresses Avoid manual configurations
* No DHCP server reservation
– You configure the IP address manually
* Difficult to change later - You must visit the device again
* A DHCP reservation is preferable
– Change the IP address from the DHCP server
64
Automatic Private IP Addressing (APIPA)
A link-local address - No forwarding by routers
* IETF has reserved 169.254.0.0 through 169.254.255.255
– First and last 256 addresses are reserved
– Functional block of169.254.1.0 through 169.254.254.255
* Automatically assigned
– Uses ARP Address Resolution Protocol to confirm the address isn’t currently in use
65
DNS Configuration
* Translates human-readable names
into computer-readable IP addresses
– You only need to remember
www.ProfessorMesser.com
* Hierarchical
– Follow the path
* Distributed database
– Many DNS servers
– 13 root server clusters (over 1,000 actual servers)
– Hundreds of generic top-level domains (gTLDs) -
.com, .org, .net, etc.
– Over 275 country code top-level domains (ccTLDs) -
.us, .ca, .uk, etc.
66
what are DNS records
* Resource Records (RR)
– The database records of domain name services
* Over 30 record types
– IP addresses, certificates, host alias names, etc.
* These are important and critical configurations
– Make sure to check your settings, backup, and test!
67
what are Address records (A) (AAAA)
* Defines the IP address of a host
– This is the most popular query
* A records are for IPv4 addresses
– Modify the A record to change the
host name to IP address resolution
* AAAA records are for IPv6 addresses
– The same DNS server, different records
68
-DNS Configuration Mail exchanger record (MX)
Determines the host name for the mail server - this isn’t an IP address; it’s a name
69
what are Text records (TXT
* Human-readable text information
– Useful public information
– Was originally designed for
informal information
* Can be used for verification purposes
– If you have access to the DNS,
then you must be the administrator
of the domain name
* Commonly used for email security
– External email servers validate
information from your DNS
70
what is Sender Policy Framework (SPF)
* SPF protocol
– A list of all servers authorized to send emails
for this domain
– Prevent mail spoofing
– Mail servers perform a check to see if incoming mail
really did come from an authorized host
71
what is Domain Keys Identified Mail (DKIM)
* Digitally sign a domain’s outgoing mail
– Validated by mail servers, not usually
seen by the end user
– The public key is in the DKIM TXT record
72
what is DMARC
* Domain-based Message Authentication, Reporting,
and Conformance (DMARC)
– Prevent unauthorized email use (spoofing)
– An extension of SPF and DKIM
* You decide what external email servers should do with
emails that don’t validate through SPF or DKIM
– That policy is written into a DMARC TXT record
– Accept all, send to spam, or reject the email
– Compliance reports can be sent to the email administrator
73
DHCP Configuration --Scope properties
* IP address range
– And excluded addresses
* Subnet mask
* Lease durations
* Other scope options
– DNS server
– Default gateway
– VOIP servers
74
DHCP Configuration --DHCP pools
* Grouping of IP addresses
– Each subnet has its own scope
– 192.168.1.0/24
– 192.168.2.0/24
– 192.168.3.0/24
– ...
* A scope is generally a single contiguous
pool of IP addresses
– DHCP exceptions can be made inside of the scope
75
DHCP Configuration --DHCP address assignment
* Dynamic assignment
– DHCP server has a big pool of addresses to give out
– Addresses are reclaimed after a lease period
* Automatic assignment
– Similar to dynamic allocation
– DHCP server keeps a list of past assignments
– You’ll always get the same IP address
76
DHCP Configuration --DHCP address allocation
* Address reservation
– Administratively configured
* Table of MAC addresses
– Each MAC address has a matching IP address
* Other names
– Static DHCP Assignment, Static DHCP,
Static Assignment, IP Reservation
77
DHCP Configuration --DHCP leases
* Leasing your address
– It’s only temporary
– But it can seem permanent
* Allocation
– Assigned a lease time by the DHCP server
– Administratively configured
* Reallocation
– Reboot your computer
– Confirms the lease
* Workstation can also manually release the IP address
– Moving to another subnet
78
DHCP Configuration --DHCP renewal
* T1 timer
– Check in with the lending DHCP server to renew
the IP address
– 50% of the lease time (by default)
* T2 timer
– If the original DHCP server is down, try rebinding
with any DHCP server
– 87.5% of the lease time (7/8ths)
79
LANs
Local Area Networks
* A group of devices in the same broadcast domain
80
Virtual LANs
Virtual Local Area Networks
* A group of devices in the same broadcast domain
* Separated logically instead of physically
81
Configuring VLANs
* Virtual Local Area Networks
– A group of devices in
the same broadcast domain
82
VPNs
* Virtual Private Networks
– Encrypted (private) data traversing a public network
* Concentrator
– Encryption/decryption access device
– Often integrated into a firewall
* Many deployment options
– Specialized cryptographic hardware
– Software-based options available
* Used with client software
– Sometimes built into the OS
83
Client-to-Site VPNs
* On-demand access from a remote device
– Software connects to a VPN concentrator
* Some software can be configured as always-on
84
Internet Connection Types -- Satellite networking
* Communication to a satellite
– Non-terrestrial communication
* High cost relative to terrestrial networking
– 50 Mbit/s down, 3 Mbit/s up are common
– Remote sites, difficult-to-network sites
* High latency
– 250 ms up, 250 ms down
– Starlink advertises 40 ms and is working on 20 ms
* High frequencies - 2 GHz
– Line of sight, rain fade
85
Internet Connection Types -- Fiber
* High speed data communication
– Frequencies of light
* Higher installation cost than copper
– Equipment is more costly
– More difficult to repair
– Communicate over long distances
* Large installation in the WAN core
– Supports very high data rates
– SONET, wavelength division multiplexing
* Fiber is slowly approaching the premises
– Business and home use
86
Internet Connection Types -- Cable broadband
* Broadband
– Transmission across multiple frequencies
– Different traffic types
* Data on the “cable” network
– DOCSIS (Data Over Cable Service Interface
Specification)
* High-speed networking
– 50 Mbits/s through 1,000+ Mbit/s are common
* Multiple services
– Data, voice, video
87
Internet Connection Types -- DSL
DSL
* ADSL (Asymmetric Digital Subscriber Line)
– Uses telephone lines
* Download speed is faster than the upload speed
(asymmetric)
– 200 Mbit/s downstream / 20 Mbit/s upstream
are common
– ~10,000 foot limitation from the central office (CO)
– Faster speeds may be possible if closer to the CO
88
Internet Connection Types -- Cellular networks
* Mobile devices
– “Cell” phones
* Separate land into “cells”
– Antenna covers a cell with certain frequencies
* Tethering
– Turn your phone into a wireless router
* Mobile hotspot
– Standalone devices
– Use your phone for other things
89
Internet Connection Types -- WISP
* Wireless Internet Service Provider
– Terrestrial internet access using wireless
* Connect rural or remote locations
– Internet access for everyone
* Many different deployment technologies
– Meshed 802.11
– 5G home internet
– Proprietary wireless
* Need an outdoor antenna
– Speeds can range from ~ 10 to 1,000 megabits per second
90
Network Types -- LAN
* Local Area Network
– Local is relative
* A building or group of buildings
– High-speed connectivity
* Ethernet and 802.11 wireless
– Any slower and it isn’t “local”
91
Network Types -- WAN
* Wide Area Network
– Spanning the globe
* Generally connects LANs across a distance
– And generally much slower than the LAN
* Many different WAN technologies
– Point-to-point serial, MPLS, etc.
– Terrestrial and non-terrestrial
92
Network Types -- PAN
* Personal Area Network
– Your own private network
– Bluetooth, IR, NFC
* Automobile
– Audio output
– Integrate with phone
* Mobile phone - Wireless headset
* Health
– Workout telemetry, daily reports
93
Network Types -- MAN
* Metropolitan Area Network
– A network in your city
– Larger than a LAN, often smaller than a WAN
* Historically MAN-specific topologies
– Metro Ethernet
* Common to see government ownership
– They “own” the right-of-way
94
Network Types -- SAN
SAN
* Storage Area Network (SAN)
– Looks and feels like a local storage device
– Block-level access
– Very efficient reading and writing
* Requires a lot of bandwidth
– May use an isolated network and high-speed
network technologies
95
Network Types -- WLAN
Wireless LAN
– 802.11 technologies
* Mobility
– Within a building
– In a limited geographical area
* Expand coverage with additional access points
– Downtown area
– Large campus
96
Network Tools -- Cable crimper
* “Pinch” the connector onto a wire
– Coaxial, twisted pair, fiber
* Connect the modular connector to
the Ethernet cable
– The final step of the process
* Metal prongs are pushed through the insulation
– The plug is also permanently pressed
onto the cable sheath
97
Network Tools -- Cable crimper best practices
* Get a good crimper
– And a good pair of electrician’s scissors / cable snips
– And a good wire stripper
* Make sure you use the correct modular connectors
– Differences between wire types
* Practice, practice, practice
– It won’t take long to become proficient
98
Network Tools --WiFi analyzer
* Wireless networks are
incredibly easy to monitor
– Everyone “hears” everything
* Purpose-built hardware or
mobile device add-on
– Specializes in 802.11 analysis
* Identify errors and interference
– Validate antenna location and installation
99
Network Tools --Tone generator
* Where does that wire go?
– Follow the tone
* Tone generator
– Puts an analog sound on the wire
* Inductive probe
– Doesn’t need to touch the copper
– Hear through a small speaker
100
Network Tools --Using the tone generator and probe
* Easy wire tracing
– Even in complex environments
* Connect the tone generator to the wire
– Modular jack, coax, punch down connectors
* Use the probe to locate the sound
– The two-tone sound is easy to find
101
Network Tools --Punch-down tools
* “Punch” a wire into a wiring block
– 66 block, 110 block, and others
* Can be tedious
– Every wire must be
individually punched
* Trims the wires during the punch
– Very efficient process
102
Network Tools --Punch-down best-practices
* Organization is key
– Lots of wires,
– Cable management
* Maintain your twists
– Your Category 6A cable will thank you later
* Document everything
– Written documentation, tags, graffiti
103
Network Tools --Cable testers
* Relatively simple
– Continuity test
* Can identify missing pins
– Or crossed wires
* Not usually used for frequency testing
– Crosstalk, signal loss, etc.
104
Network Tools --Loopback plugs
* Useful for testing physical ports
– Or fooling your applications
* Serial / RS-232 (9 pin or 25 pin)
* Network connections
– Ethernet, T1, Fiber
* These are not cross-over cables
105
Network Tools --Taps and Port Mirrors
* Intercept network traffic
– Send a copy to a packet capture device
* Physical taps
– Disconnect the link, put a tap in the middle
– Can be an active or passive tap
* Port mirror
– Port redirection, SPAN (Switched Port ANalyzer)
– Software-based tap
– Limited functionality, but can work well in a pinch
