Classless Addressing (Part 1)
Summary
TLDRThis lecture discusses the limitations of classful IP addressing, which categorizes addresses into five classes and often leads to IP address wastage. It highlights the drawbacks, such as lack of flexibility, inefficient address use, and increased routing table entries, which necessitate the transition to classless addressing. Classless addressing allows for a more efficient and flexible allocation of IP addresses based on actual network requirements, reducing waste and improving routing performance.
Takeaways
- đ Classful addressing in IPv4 is divided into five classes: A, B, C, D, and E, with A, B, and C being the most commonly used for general purposes.
- đ In classful addressing, a Class C network can support up to 254 hosts, but if more hosts are needed, a larger class like B is required, which can support up to 65,534 hosts.
- đą The script highlights a specific example where a requirement of 300 devices leads to the necessity of using Class B, resulting in the waste of 65,234 IP addresses.
- đą Large organizations face the drawback of classful addressing due to the lack of flexibility in internal address allocation, as they are assigned large blocks of addresses that may not match the network structure.
- đ Classful addressing leads to inefficient use of address space, as only three classes are used for general purposes, and the existence of three block sizes can lead to waste.
- đ The growth of the internet requires routers to handle more routing table entries, which can cause performance issues due to the proliferation of routing table entries in classful addressing.
- đ« One of the main drawbacks of classful addressing is the lack of internal address flexibility, inefficient use of address space, and the increase in routing table entries.
- đ The transition from classful to classless addressing is necessary to address the issues of IP address wastage and routing table inefficiencies.
- đĄ Classless addressing allows for the creation of subnet masks based on the actual needs of the network, enabling more efficient use of IP addresses.
- đ In classless addressing, networks can be designed to use IP addresses sparingly, reducing waste compared to classful addressing.
- đ The lecture concludes by emphasizing the understanding of the drawbacks of classful addressing and the advantages of classless addressing for efficient IP address utilization.
Q & A
What is classful addressing in IP networking?
-Classful addressing refers to the system of IP version 4 (IPv4) where there are five classes of addresses: A, B, C, D, and E, with classes A, B, and C being used for general purposes. Each class has a fixed subnet mask and a maximum number of hosts it can support.
What is the maximum number of hosts that can be supported in a Class C network?
-A Class C network can support up to 254 hosts.
Why might Class B addressing be inefficient for a network that requires only 300 devices?
-Class B addressing is inefficient for a network requiring only 300 devices because it can support up to 65,534 hosts, which means that 65,234 IP addresses would be wasted.
What is the main drawback of classful addressing when it comes to IP address allocation?
-The main drawback of classful addressing is the inefficient use of IP address space due to the fixed subnet masks and the large blocks of addresses that may not match the underlying network structure.
How does classful addressing affect the routing table entries in routers?
-Classful addressing can lead to the proliferation of routing table entries as routers need to store more entries to handle the routing of IP datagrams, which can cause performance problems.
What is the maximum number of hosts that can be supported in a Class A network?
-A Class A network can support 1,677,214 hosts.
How does classless addressing address the issue of IP address wastage compared to classful addressing?
-Classless addressing allows for the creation of custom subnet masks and more efficient use of IP addresses based on the actual requirements of the network, thus reducing wastage.
What is one of the main benefits of classless addressing over classful addressing?
-One main benefit of classless addressing is the lack of internal address flexibility, allowing for a better match between the assigned address blocks and the structure of the underlying internal network.
Why is it necessary to migrate from classful to classless addressing?
-It is necessary to migrate from classful to classless addressing to address the drawbacks of classful addressing, such as lack of flexibility, inefficient use of address space, and the proliferation of routing table entries.
Can you give an example of how classless addressing allows for more efficient IP address usage?
-In classless addressing, if a network requires only 25 computers, it can create a custom subnet mask that allows for exactly 25 usable IP addresses, thus avoiding the wastage of addresses that would occur with classful addressing.
What is the impact of classless addressing on the size of routing tables in routers?
-Classless addressing can potentially reduce the size of routing tables by allowing for more efficient allocation of IP addresses, which in turn can reduce the number of entries required in routing tables.
Outlines
đ Introduction to Classful Addressing Drawbacks
This paragraph introduces the concept of classful addressing in IPv4, highlighting its limitations and inefficiencies. It explains the five classes of IPv4 addresses (A, B, C, D, and E), with a focus on A, B, and C for general use. The speaker illustrates the issue of IP address wastage by providing examples, such as needing a Class B network for 300 devices when Class C would suffice, resulting in the waste of 65,234 IP addresses. The paragraph also discusses the lack of address flexibility for large organizations and the inefficient use of the limited IP address space due to the existence of three block sizes. Furthermore, it touches on the proliferation of routing table entries as a performance issue for routers, emphasizing the need to transition from classful to classless addressing to conserve IP addresses and improve network efficiency.
đ Transition to Classless Addressing
The second paragraph delves into the migration from classful to classless addressing, emphasizing the benefits of the latter. Classless addressing allows for a more efficient and flexible use of the IP address space, enabling the creation of subnet masks tailored to the specific needs of a network. The speaker provides an example where a network with only 25 computers can be designed with a custom subnet mask, thereby sparingly using IP addresses. This method contrasts with classful addressing, which does not allow for such customization and leads to significant IP address wastage. The paragraph concludes by summarizing the drawbacks of classful addressing and the advantages of classless addressing, encouraging the adoption of the latter for better IP address management and network design.
Mindmap
Keywords
đĄClassful Addressing
đĄClassless Addressing
đĄIPv4
đĄSubnet Mask
đĄIP Address Waste
đĄRouting Table
đĄInternal Address Flexibility
đĄInefficient Use of Address Space
đĄProliferation of Routing Table Entries
đĄIP Address Allocation
đĄNetwork Mask
Highlights
Introduction to classless addressing as an alternative to classful addressing.
Explanation of classful addressing with its five classes: A, B, C, D, and E, with A, B, and C being most commonly used.
Limitation of class C networks to 254 hosts and the need for class B for networks requiring more than 254 hosts.
Waste of IP addresses in class B networks when the requirement is less than the maximum capacity.
Class A networks catering to a vast number of hosts, but leading to IP address wastage for smaller requirements.
Drawbacks of classful addressing including lack of address flexibility and inefficient use of address space.
The impact of classful addressing on routing tables, causing performance issues for routers.
The need for migration from classful to classless addressing due to the inefficiencies and limitations of classful addressing.
Classless addressing allows for the sparing use of IP addresses based on actual network requirements.
Classless addressing reduces the wastage of IP addresses compared to classful addressing.
The ability to create custom subnet masks in classless addressing for precise network requirements.
Practical example of creating a network for 25 computers using classless addressing to avoid IP wastage.
The importance of classless addressing in conserving the limited IP address space.
Comparison of classful and classless addressing in terms of IP address conservation and network efficiency.
The conclusion emphasizing the understanding of classful addressing drawbacks and the necessity of classless addressing.
End of the lecture with a thank you note and applause.
Transcripts
in the previous lectures we have seen
classful addressing
and today we will see classless
addressing part one what we are going to
deal in part one upon the completion of
this session the learner will be able to
outcome number one we will know the
drawbacks of classful addressing and
outcome number two we will understand
the need for classless addressing let's
start with what is class full addressing
in classful ipv for addressing we have
five classes of ipv for addresses class
a b c d and e and class a b c are used
for our general purpose
suppose if we want to create a network
with 200 devices then we can obviously
go for classy any classy network can
cater up to 254 hosts
in case if our requirement is 300 so we
can't go for classy because in class c
the maximum number of hosts or devices
possible is 254 only
in order to handle 300 devices we need
to go to class b so in class b we can
have a maximum of 65
534 hosts possible per network in case
if our requirement is just 300 no other
way we need to go for class b but class
b wastes a lot of ip addresses in the
example we have taken we need to create
a network that uses 300 devices or that
contains 300 devices so obviously we
can't go for class c so we need to go to
class b but if we note in class b
it can have a maximum of 65 534 hosts or
devices or ip addresses but our
requirement is just 300 so 65 534 minus
300 is 65
234 ip addresses we are going to waste
that's a huge set of ip addresses we are
wasting
and that's the main drawback of class
full addressing
in case if we want to have a network
which needs 80 000 ip addresses so
obviously we cannot use class b so we
need to go to class a where class a is a
big number of network where it can cater
1 crore 67 lakh 77
214 hosts possible per network so
classful addressing obviously wastes ip
addresses say if i want to create a
network that needs only five devices i
need to obviously go for class c because
in a classful world class c has this
many networks wherein in each network we
can have
254 hosts but our requirement is just
five so obviously we are going to waste
249 ip addresses
let's now analyze the drawbacks of
classful addressing basically classful
addressing has the lack of internal
address flexibility big organizations
are assigned large monolithic blocks of
addresses that don't match well the
structure of the underlying internal
network so if we have a big organization
since big organization needs either
class b or class c so these block of
addresses that do not exactly match the
underlying internal network
and the second drawback is inefficient
use of address space we know there are
five classes of ipv4 addresses and we
have only three classes that are used
for our general purpose so the existence
of three block sizes may be class a b
and c leads to waste of limited ip
address space we already seen this in
the previous slide class full addressing
vs ip addresses
and also the third drawback is
proliferation of routing table entries
we know a switch is going to store the
mac address table whereas a router is
going to store the routing table routing
tables are really needed in order to
take a decision to forward the packets
as the internet grows more and more
entries are required for routers to
handle the routing of ip datagrams which
causes performance problems for routers
attempting to reduce inefficient address
space allocation leads to even more
routing table entries if we take a
router that router is also going to have
some memory and this memory is going to
store the routing table in a routing
table the ip addresses are going to be
stored what happens if the routing table
is a very big one it's getting increased
periodically router also has a limited
memory size right it can't handle all ip
addresses in the routing table so when
we go for class full addressing we have
this drawback too so basically the
drawbacks of classful addressing
includes lack of internal address
flexibility inefficient use of address
space and the proliferation of router
table entries or routing table entries
and because of these problems we need to
migrate from class full addressing to
classless addressing in a nutshell
classful addressing waste type addresses
so we need to sparingly use the ip
addresses but with classful addressing
that is with the fixed subnet mask it's
not possible to save the ip addresses so
that's why we are migrating towards
classless addressing in classless
addressing we are going to use the ip
address space sparingly and based on the
need as well suppose if we are going to
create a network which is going to have
only 25 computers we can create our own
subnet mask and we can create our own
network by sparingly used ip addresses
so sparring usage of ip address is not
possible in class full addressing
whereas it is made possible in classless
addressing classless addressing also
weighs some ip addresses but not that
much when compared to class full
addressing and that's it guys i hope now
you know the drawbacks of glassfull
addressing and we understood the need
for classless addressing
i hope you guys enjoyed the lecture and
thank you for watching
[Music]
[Applause]
[Music]
you
Voir Plus de Vidéos Connexes
5.0 / 5 (0 votes)