Notes from 24/06/2020

IPv6 (Internet protocol version 6)
The INTERNET ENGINEERING TASK FORCE , IETF ( organization responsible for defining the IP standards ). In 1980's the IETF developed IPv4 but as internet explosion took place in 1990s , The TETF realized that they might need the new protocol standards for the Next generation .

IPv6 is the second network layer standard protocol that follows IPv4 , it offers increased address size , a streamlined header format , extensible headers & the ability to provide confidentiality and integrity of communications.

the following list summarizes the characteristics of IPv6 and the improvements it can deliver:

• Larger address space: Increased address size from 32 bits to 128 bits
• Streamlined protocol header: Improves packet-forwarding efficiency
• Stateless autoconfiguration: The ability for nodes to determine their own address
• Multicast: Increased use of efficient one-to-many communications
• Jumbograms: The ability to have very large packet payloads for greater efficiency
• Network layer security: Encryption and authentication of communications
• Quality of service (QoS) capabilities: QoS markings of packets and flow labels that help identify priority traffic
• Anycast: Redundant services using nonunique addresses
• Mobility: Simpler handling of mobile or roaming nodes

Running both IPv4 and IPv6 at the same time, called dual stack, is one of the primary transition strategies .

IPV6 is written if the following format.
xxxxxxxxxxxxxxxx.xxxxxxxxxxxxxxxx.xxxxxxxxxxxxxxxx.xxxxxxxxxxxxxxxx.
xxxxxxxxxxxxxxxx.xxxxxxxxxxxxxxxx.xxxxxxxxxxxxxxxx.xxxxxxxxxxxxxxxx = 128 bits
0-(2^16-1)
HHHH:HHHH:HHHH:HHHH:HHHH:HHHH:HHHH:HHHH


MODES OF ADDRESSING (Casting)
The term casting is used to describe the different ways in which data can be sent to recipients. In IPv4 there are three methods called:

• Unicast
• Multicast
• Broadcast

Unicast
In unicast a single sender transmits data to a single receiver. Unicast is the simplest form of transmission and is the predominant form of data transfer on the majority of networks. Unicast gradually becomes less efficient as more receivers need to see identical data. In this scenario, many unicast packets are sent to unique destinations, hence the other two forms of transmission.

Multicast
In multicast, one or more senders transmit to a group of receivers. Devices ‘subscribe’ to become members of a multicast group. The multicast group is then allocated an IP address such that all members can receive data directed to that group.

Broadcast
In broadcast, one or more senders transmit data to all receivers. This is very beneficial in some circumstances, particularly for network management packets such as ARP (Address Resolution Protocol) and RIP (Routing Information Protocol) where all devices must see the data.


VPN (Virtual Private Network)

A service that encrypts your internet traffic and protects your online identity , by redirecting your connections to the internet through a remote server run by a VPN provider , this way it makes us secure. It hides our IP address and encrypts all the data we send or receive.

The VPN  renegotiate the encrypting hash in 8-24 hours , require authentication , has access control and provides data security .

ACCESS CONTROL LIST 

It controls what data users can access and how they can access it. ACL require users to pass a set of requirements in order to gain access to the particular data. Each ACL rule specifies:

•  the object and operation being secured 
• the permission required to access the object 

The types of access control could be summarized as:

• outbount access control : for exiting 
• inbount access control: for entering