establish encrypted communications between web servers/clients
encrypts the data received from L7 and passes encrypted data to L5
decrypts the data received from L5 and passes decrypted data to L7
leveraged by HTTPS protocol
provides privacy and data integrity
uses public-key exchange
version 1, 2, 3, all deprecated
TLS
transport layer security protocol
successor of SSL
1999, by IETF
L6 (layer 6 - presentation layer thing)
establish encrypted communications between web servers/clients
encrypts the data received from L7 and passes encrypted data to L5
decrypts the data received from L5 and passes decrypted data to L7
leveraged by HTTPS protocol, can be used
provides privacy and data integrity
version 1.0, 1.1 are deprecated and 1.2 & 1.3 are available
SSL vs TLS
In short, a better version of SSL
https://www.ssl2buy.com/wiki/ssl-vs-tls
There is no SSL certificate and TLS certificates, they're just certificates which works for both the protocols
both are X.509 digital certificates that helps authenticate the server and facilitate the handshake process
TLS SNI: Server Name Indication, is an addition to the TLS encryption protocol that enables a client device to specify the domain name it is trying to reach in the first step of the TLS handshake, preventing common name mismatch errors.
DSCP
Differentiated Services Code Point
Is a packet header value
That can be used to request (for example) high priority or best effort delivery of the traffic
Related
Devices: TBD
Layer: TBD
DHCP
Dynamic Hosting Configuration Protocol
L2-L3 (Network Layer to Transport Layer)
Is a NMP (N/W management protocol), helps automate the process of configuring devices on IP networks
Thus assigning devices IP address
so that IPs don't need to be manually assigned by an admin each time a device connects
Thus allowing them to use network service like NAT, DNS and any communication protocols based on UDP or TCP
DHCP is also responsible for the configuration of domain name server (DNS) and subnet masks, as well as default gateways
Related
Devices: Router/Gateway
OSI Layer: 2-3
NAT
Network Address Translation
Is a method of remapping an IP address space into another by modifying the network address information in IP header of packets while they are in transit across a traffic routing device
Means, it enables private IP networks that uses unregistered IP address to connect to internet
by translating the unregistered (not globally unique) IP addresses in internal network into legal address
is a switch feature that allows the devices to be provisioned and configured automatically, eliminating most of the manual labor involved with adding them to a network
MDNS (multicast DNS)
DNS
Domain Name System
translates Name to IP address
Is a hierarchical and decentralized naming system
For computers, services or other resources connected to internet or private network
Related
Devices: TBD
Layer: L3 (Transport Layer thing)
process
hit a URL (say api.example.com)
DNS lookup starts
queries recursive resolver which can be ISP, wireless carrier, etc.
recursive resolver redirects the query to root server
root server keeps map of all the top level domain (e.g. .com, .net) with top level domain (TLD) server's address
root server redirects the query for .com part to a TLD server
TLD server keeps map of all the top level domains with domain's name server
TLD server finds the domain's name server for example.com and redirects the query there
domain's name server keeps map of all the subdomains with IP address
request reaches to domain's DNS server with unsolved puzzle part (i.e. api.example.com)
domain's DNS server returns the IP address to recursive resolver server
recursive resolver server shares the IP address with client/browser
A decibel is a logarithmic unit that is a ratio of the power of the system to some reference
10 dBm (1mW) is 10 times powerful than 0 dBm
20 dBm (100mW) is 10 times powerful than 10 dBm
RX (Receive) vs. TX (Transmit)
Ionizing vs non-ionizing radiation
5G vs WiFi6
WiFi naming convention for past and current generation tech has been simplified
Wi-Fi 6 means 802.11ax technology – the new generation of Wi-Fi, present in many new routers you'll buy from now on - but not many devices as yet.
enhancement: at PHY layer, better traffic management, better multi-client mgnt
Wi-Fi 5 means 802.11ac technology – effectively the current generation
Wi-Fi 4 means 802.11n technology – many people will have networking gear based on 802.11n, but it was replaced by 802.11ac in many new routers from 2013 on.
WiFi6 > 5G
OEM original equipment manufacturer
OUI organizationally unique identifier
a 24-bit number that uniquely identifies a vendor, manufacturer, or other organization