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| 1 | +* Cloud |
| 2 | +--------- |
| 3 | +-> Cloud computing - Technological approach where computing resources are provisioned in a shareable way, so that lots of users get what they need; |
| 4 | +-> Provide services by sharing resources; |
| 5 | + |
| 6 | +-> Hardware Virtualization - a physical machine and a logical machine can be abstracted away from each other. |
| 7 | +-> Virtualization - A single physical machine called a host could run many individual virtual instances called guests; |
| 8 | + |
| 9 | +-> Hardware Virtualization platforms employ hypervisor; |
| 10 | +-> Hypervisor - A piece of software that runs and manages virtual machines while also offering these guests a virtual operating platform that's indistinguishable from actual hardware; |
| 11 | + |
| 12 | +-> Public Cloud - A large cluster of machines run by another company; |
| 13 | +-> Private Cloud - Used by a single large cooperation and generally hosted on its own premises; |
| 14 | +-> Hybrid Cloud - Public & Private Cloud; |
| 15 | +------------------------------------------------------------------------------------------------------------------------------------------- |
| 16 | +* Services |
| 17 | +----------- |
| 18 | +-> X as a Service |
| 19 | +-> IaaS - Infrastructure as a Service - use others network and servers; (abstracts away the infrastructure) |
| 20 | +-> Paas - Platform as a Service - platform is provided for customers to run their services - execution engine; |
| 21 | +-> Saas - Software as a Service - (abstracts away the server needed) - licensing the use of software to others while keeping the software centrally hosted and managed; - gmail for business / office 365 outlook; |
| 22 | +---------------------------------------------------------------------------------------------------------------------------------------- |
| 23 | +* Cloud storage - duplicate data and ready available across geographic ; |
| 24 | +---------------------------------------------------------------------------------------------------------------------------------------- |
| 25 | +* IPv6 Addressing and Subnetting : |
| 26 | +---------------------------------- |
| 27 | +- Address -> 128-bit | IPV4 - 32-bit; |
| 28 | +- 8 groups of 16 bits - each group - 4 hexadecimal numbers; |
| 29 | +- Network id - 64-bits | Host id - 64 bits; |
| 30 | +- begins with 2001:0db8 -> documentation and education; |
| 31 | +- FF00:: - multicast (addressing hosts all at once); |
| 32 | +- FE80:: - Link-local unicast addresses - allow for local network segment communications and are configured based on a host's MAC address; - receive n/w configurations; |
| 33 | +- loopback address - ::1 localhost |
| 34 | + |
| 35 | +IPV6 compression |
| 36 | +--------------- |
| 37 | +- remove any leading zeros from group; |
| 38 | +- consecutive groups of zeros can be replaced with ::; |
| 39 | +- only once; |
| 40 | +---------------------------------------------------------------------------------------------------------------------------------------- |
| 41 | +*IPv6 Header: |
| 42 | +------------- |
| 43 | +- Version - 4 bit; |
| 44 | +- Class - (traffic class) - 8 bit; |
| 45 | +- Flow label - 20 bit; |
| 46 | +- Payload length - 16 bit; |
| 47 | +- Next header - optional ; |
| 48 | +- Hop limit - 8 bit - identical to TTL field in IPV4; |
| 49 | +- Source address - 128 |
| 50 | +- Destination address - 128 |
| 51 | +- Data payload; |
| 52 | +---------------------------------------------------------------------------------------------------------------------------------------- |
| 53 | +* IPv4 and IPv6 harmony |
| 54 | +----------------------- |
| 55 | +- IPV4 mapped address space - ipv6 address space that can be directly correlated to IPv4 address (80 zeros follwed by 16 ones) ; |
| 56 | +- IPV6 -> ipv4 -> IPv6 tunnels |
| 57 | +-> IPV6 tunnes -> |
| 58 | +IPV6 server -------IPV6 traffic--------Encapuslate IPv4 datagram ----------------- IPV6 server; |
| 59 | +- IPV6 tunnel brokers - companies that IPV6 tunneling provide endpoints; |
| 60 | +---------------------------------------------------------------------------------------------------------------------------------------- |
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