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Showing posts from February, 2016

Internet Protocol version 6 (IPv6)

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It’s been few weeks since my last article. So today I'll be talking about IPv6. The next generation of the internet protocol is IPv6. What is IPv6? Internet Protocol version 6 was developed by the Internet Engineering Task Force(IETF), which was starting in 1993 in response to a series of perceived problems, primarily with the exhaustion of the current, IP version 4(IPv4) address space. Simply IPv6 is the replacement internet protocol for Ipv4. With the 32 bit address format, IPv4 can handle a maximum of 4.3 billion unique IP addresses. With its 128-bit address format, IPv6 can support 3.4 x 10 38 unique IP addresses. There are different types of IPv6 addresses: Unicast, Anycast and Multicast. Unicast addresses are the well known addresses. A packet sent to a unicast address arrives exactly at the interface belonging to the address. Anycast addresses are syntactically indistinguishable from unicast addresses but they address a group of interfaces. The packet de

CAP THEOREM

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What’s C, A and P? Consistency is the easiest one. It roughly means that the clients get the same view of data. By saying that a system is consistent we often mean strong consistency, but it also can come in different flavors. Availability is a property saying that every request to a non-failing node will return a (meaningful) response. The response may not contain all data (so the harvest will not be 100%), but it should be useful for the client. Partition tolerance means that the system will continue working even if any number of messages sent between nodes is lost. This can be e.g. a network failure between two data centers, where nodes in each data center form a partition. Also note that a failure of any number of nodes forms a partition (it is not possible to distinguish between a network failure and a node failing and stopping to respond to messages). The basic statement of the CAP theorem is that, given the three properties of Consistency, Availability, and Pa