- every interface into a network needs a unique identifier - the TCP/IP Model uses the ip address for this - the ip model has 4 layers: - application - transport - internet layer determines the path of packets from source to host - network access - ip addresses are 32 bit address in v4 - there are 5 classes of ipv4, A to E - class E is reserved and not used for communication - class A B and C are used for communication only - subnet mask is used to specify which bits of the ip address are used for the network bits - network bits are all 1s up to the next . - in decimal seen as 255. - the broadcast address has all the network bits and all 1s in place of the host bits - network address is the network bits and 0s in place of the host bits - subnetting is the process of splitting a network into smaller networks - there are 2^n -2 usable subnets where n is number of host bits when not subnetting - if subnetting =2^m -2 - thus number of usable hosts per subnet = 2^n-m -2 -
In our last post, we talked about the physical structures that underlie the net - the fiber optic cables and data centers that comprise the backbone of the internet.
Here, CODE.org shares a fun series of videos that explain the electronic part of the equation - how information actually gets from your computer to wherever its going and back. They even brought in Vint Cerf, one of the “fathers of the internet”, to help explain.
We think you should know these basics - because the better you understand the net, the better you’ll be at communicating securely, avoiding surveillance, and securing your data. Which is to say, the better you’ll be at not getting arrested, infiltrated, or harmed.
Bitcoin micropayments: Coming to smartphones—and toasters?—everywhere
Micropayments might not top your list of most compelling inventions, but they’re a sought-after capability. Small payments of less than a dollar, or even less than a cent, have the potential to shake up old, established business models, and open up new doors for the Internet of Everything.
Small digital payments have been tried again and again—in fact, Web inventor Tim Berners-Lee tried to embed micropayment capability into the original World Wide Web, but without success. So far, inherent transaction costs have been an unsurpassable hurdle.
Some argue that digital payment methods like bitcoin are the way forward.
Top 15 Interview Questions with Answers
for Network Administrators
Q-1: What is Active Directory?
Active Directory provides a centralized control for network administration and
security. Server computers configured with Active Directory are known as domain
controllers. Active Directory stores all information and settings for a
deployment in a central database, and allows administrators to assign policies
and deploy and update software.
Q-2: What is NetBIOS protocol?
NetBIOS (Network Basic Input/Output System) Protocol allows applications on
separate computers to communicate over a LAN. It runs over TCP/IP giving each
computer in the network a NetBIOS name and IP address. E.g. It can be used for
computers running Windows 2000 (or before) to join a computer network running
Windows 2000 (or later).
and NAS are two different storage systems; difference between them is the cost
and complexity to use and operate the storage system.
• Network-attached storage is less costly than Storage area networks for its
users to handle and operate.
• Network-attached storage uses TCP/IP network protocol and applications such
as NFS or CIFS for file access.
• Managing Network-attached storage is a lot easier
than Storage area networks.
• Storage area networks can cater to a large scale
of users but Network-attached storage cannot but the change is coming.
• Network-attached storages are efficient for
organizing and delivering data to clients over the network and data can be
transferred over long distances efficiently.
• The major difference between the two storage
networks is the cost and complexity to use and operate the storage system.
Map of the fifteen node ARPANET in 1971, redrawn by Janet Abbate from Bolt, Beranek and Newman’s original. ARPANET launched in 1969 and was the first TCP/IP packet switching network, technologies used by today’s internet. ARPANET was decommissioned in 1990.