Week 5– CST– 311 Intro to Computer
Networks
Module 5 – The Network Layer - Data Plane
This week we studied the Network Layer. We learned about
routing and forwarding. Forwarding is when the router moves the packets it receives
from its input link to the appropriate output links. Routing is the route determined
by routing algorithms which the packet must travel to get to its destination. I
like the analogy that the power point slides use to describe forward and
routing. If you are traveling through the United States by car from Boston to
San Francisco, the routing would be the cities and roads you plan to take to
get to San Francisco. Forwarding would be the process of entering and leaving
each city because you will enter through a certain road (input port) and must choose
which road you need to take to leave the city.
We also studied some of the scheduling algorithms
which we have become familiar with throughout the program. Because packet loss occurs
when packets arrive at a full queue, scheduling must be used to choose the next
packet to send on the link. The algorithms covered in the book were FIFO, Round
Robin, and Weighted Fair Queuing.
Another network layer subject we covered was IPv4. It
uses Dotted Decimal Notation for IP addresses. It is a 32-bit address that is
divided by decimals into 4 bytes and each byte has the range of 0 – 255. The
first section of the address is the network prefix, and the second part is the
host number.
Lastly, we covered IPv6. IPv6 is the successor to
IPv4. In the 1990’s, engineers realized that the 32-bit address space was not
going to be enough and will be used up somewhere between the years 2008 and
2018. Some of the features of IPv6 include auto-reconfiguration and renumbering
of IP addresses, encryption and authentication built-in, and end-to-end
connection integrity. It is a 128-bit address represented in hexadecimal where
one hex digit equals 4 bits. It is made up of eight 16-bit hextets between 0000
and FFFF separated by colons. According to our text, the transition from IPv4
to IPv6 will not only ensure we do not run out of IP addresses but “every grain
of sand on the planet can be IP addressable.”
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