SO-DIMM
Small Outline Dual In-line Memory Module
- Memory form factor common in laptops and cellular devices.
- Often easy to install.
SSD
Solid-State Drive
- Increased speed
- Less latency
- Silent (no moving parts)
LCD
Liquid Crystal Display
- Backlit (Florescent, LED, etc.)
1. TN (Twisted Nematic)
- Original LCD tech
- Fast response times (gaming!)
- Poor viewing angles - color shifts
2. IPS (In Plane Switching)
- Excellent color representation
- More expensive to produce than TN
3. VA (Vertical Alignment)
- A good compromise between TN & IPS
- Good color representation
- Slower response times than TN
OLED
Organic Light emitting Diode
- Organic compound emits light (no backlight)
- Thinner & Lighter
- Very accurate color
- More expensive
GSM
Global System for Mobile Communications
- Mobile networking standard
was 90% of the market
- Originally an EU standard
- Worldwide coverage
Used by AT&T and T-Mobile in the US
- Move your SIM card (Subscriber Identity Module) from phone to phone
Original GSM standard used Multiplexing
- Everyone gets a little slice of time
2G Networks
Consisted of 2 global standards:
GSM - Global System for Mobile Communications
CDMA - Code Division Multiple Access
CDMA
Code Division Multiple Access
- Everyone communicates at the same time
- Each call uses a different code
- The codes are used to filter each call on the receiving side
Used by Verizon & Sprint
- Handsets are controlled by the network provider
- Not much adopter elsewhere
3G technology
3rd Generation introduced in 1998
Upgraded data connectivity over 2G
- Incremental 3G updates improved speeds
- Usually several megabits per second
Bandwidth improvement allowed new functionality
- GPS
- Mobile TV
- Video on demand
4G and LTE
Long Term Evolution (LTE)
- A “4G” technology
- Converged standard (GSM and CDMA providers)
- Based on GSM and EDGE (Enhanced Data Rates for GSM Evolution)
- Standard supports download rates of 150 Mbits/s
LTE-A (LTE Advanced)
- Standard supports download rates of 300 Mbit/s
5G
Fifth Generation cellular networking
- Launched worldwide in 2020
Significant performance improvements
- At higher frequencies
PRL
Preferred Roaming List
- Tells your mobile device where appropriate towers are for the network you are using.
- OTA (Over The Air) update keeps list current
WiFi Hot Spot
Extends your cellular data network to devices using 802.11
- If provider supports Mobile Hot Spots it may be at an additional charge
GPS
Global Positioning System:
Created by the US Department of Defense
- Over 30 satellites currently in orbit.
Precise Navigation
- Need to see at least 4 satellites
Determines location based on timing differences
- Longitude, Latitude, Altitude
Mobile device location services and geotracking
- Maps, directions
- Determine physical location based on GPS, WiFi, and cell towers
MDM
Mobile Device Management:
Manage company-owned and user-owned mobile devices
Centralized management of mobile devices
- Specialized functionality
Set policies on apps, data, camera, etc.
- Control the remote device
- The entire device or “partition”
Manage access control
- Force screen locks and PINs on these single user devices
Corporate Email Configuration
- Configured for user
- MDM makes changes
- Account details, server address, communication method
2-factor authentication
- Require specific authentication types
- Biometrics, pseudo-random authentication app
Corporate Apps
- Allow or restrict app installation
- Prevent unauthorized app usage
TCP
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
UDP
User Datagram Protocol
Connectionless
- No formal open or 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
Real-time communication
- No way to stop or resend data
- Time doesn’t stop for your network
Connectionless protocols
- DHCP (Dynamic Host Configuration Protocol)
- TFTP (Trivial File Transfer Protocol)
The data might not get through
- The application keeps track and decides what to do
- It might not do anything
Ephemeral ports
ports 1,024 - 65,535
Temporary port numbers
Determined in real time by the client
Non-ephemeral ports
Ports 0 - 1,023
Permanent port numbers
Usually on a server or service
FTP
File Transfer Protocol
tcp/20 (active mode data)
tcp/21 (control)
Transfers files between systems
Authenticates with a username and password
- Some systems use a generic/anonymous login
Full-featured functionality
- List, add, delete, etc.
SSH
Secure Shell:
Provides a terminal/commandline front end connection to a remote device
Our end shows as plain text, data sent is encrypted.
Encrypted communication link - tcp/22
Looks and acts the same as Telnet
Telnet
Telecommunication Network protocol
tcp/23
Login to devices remotely
-Console access
In-the-clear communication
- Not the best choice for production systems
SMTP
Simple Mail Transfer Protocol:
tcp/25
server to server email transfer
Also used to send mail from a device to a mail server
- Commonly configurated on mobile devices and email
Other protocols are used for clients to receive email
- IMAP, POP3
DNS
Domain Name System:
udp/53
Converts names to IP addresses
DHCP
Dynamic Host Configuration Protocol:
udp/67, udp/68
Required a DHCP server
- Server, appliance, integrated into a SOHO router, etc.
Dynamic / pooled
- IP addresses are assigned in real-time from a pool
- Each system is given a lease and must renew at set intervals
DHCP reservation
- Addresses are assigned by MAC address in the DHCP server
- Manage addresses from one location
