Chapter 8: TCP/IP Network Design
Network design with Classfull IP Addressing
Classless Addressing and
Quiz:
Untuk alamat IP dibawah ini (classful IP), sebutkan :
Representasi binernya Kelasnya
Network ID, rentang IP Host, dan IP Broadcast nya
a. 175.175.240.7
b. 192.168.59.95
IP Addressing
1.
Classfull
Conventional/ Default/ Standard Net Mask
SubNetting
2.
Classless
Variable Length Subnet Mask (VLSM)
TCP/IP Network Design
1. Network design with Classfull IP
Addressing
1. Classful IP Addressing
There are three basic classes of addresses
Classful IP Addressing
Classful addresses are broken apart on octet
boundaries.
The first few bits of each segment address is
used to denote the address class of the segment.
The class ID plus network ID portions of the
Private
IPv4 address spaces
8
Public Versus Private IP Addresses
Some IP services require what’s called a secure end-to-end connection—IP traffic must be able to move in encrypted form between the sender and receiver
without intermediate translation
Most organizations need public IP addresses only for
two classes of equipment:
Devices that permit organizations to attach networks to the
Internet
Subnetting
When IP address classes were established, networks
were composed of a relatively small number of relatively expensive computers.
As time went on and the PC exploded into LAN’s, the
strict boundaries of the classful addressing address classes became restrictive and forced an inefficient allocation of addresses.
Class C address with its limit of 254 (28-2) hosts per
Subnetting
Networks grew and needed to be divided or
segmented in order to improve traffic flow.
Routers join two separate net-works.
Networks that are separated by routers must
have different network IDs so that the router can distinguish between them.
This accelerated the depletion of IP
RFC 950
RFC 950 gave users a way to subnet, or
provide a third layer of organization or
hierarchy between the existing network ID and the existing host ID.
Since the network IDs could not be altered,
the only choice was to “borrow” some of the
host ID bits.
These “borrowed” bits constitute the subnet portion of the address.
A subnet mask identifies which bits are used
Extended Network Prefix
The extended network prefix is the classful network
prefix (/16 in the case of a Class B address) plus the number of bits borrowed from the host ID
This figure illustrates the network prefix, extended
Subnet Masks
Alternative Subnet masks
for a Class B
Contoh 1: subnetting
Bank XYZ memiliki alamat Jaringan IP 131.179.0.0 Saat ini bank tersebut memiliki 50 kantor cabang.
Dalam 5 tahun ke depan diperkirakan jumlah tersebut akan meningkat menjadi 150 kantor cabang.
Setiap kantor cabang memiliki sebuah subnet, yang
maksimal akan terdiri dari 50 host.
Tentukan subnet mask yang sesuai untuk
Latihan: Langkah-langkah penyelesaian (2)
1. Tentukan kelas IP Address: 131.179.0.0
• Kelas B
• Netmask (default) = 255.255.0.0
2. Hitung jumlah subnet yang dibutuhkan
• 150 kantor cabang = 150 subnet, butuh minimum 8 bit
• 255.255.255.0 (terjawab)
3. Periksa apakah sisa bit memenuhi kebutuhan host
• Tiap subnet butuh hingga 50 host
Contoh 2: Subnetting
• Sebuah jaringan toko eceran, bernama ABC, saat ini
memiliki 80 toko. Diperkirakan perkembangannya adalah 20 toko/ tahun, selama 8 tahun ke depan.
• Setiap hari diperlukan upload data penjualan dari masing-masing toko ke kantor pusat. Dengan begitu tiap toko
memerlukan sebuah router dan sebuah komputer yang terhubung ke router tersebut (tiap toko merupakan
subnet yg butuh 2 host ID).
• Alamat Jaringan IP yang dimiliki jaringan toko tersebut adalah 165.32.0.0
Alamat IP kelas apakah yang dimiliki jaringan toko ABC? Tuliskan representasi binernya.
165.32.0.0
10100101.00100000.00000000.00000000
IP kelas B, sehingga network mask nya
Hitung kebutuhan maksimal subnet jaringan tersebut, hingga 8 tahun ke depan. Kemudian putuskan
subnetting yang paling sesuai (classfull).
80+(8x20) = 240 , jadi toko
membutuhkan minimal
240 subnet
.
Untuk memenuhi kebutuhan tersebut
maka digunakan 8 (2
8) bit subnet mask
255.255.
255
.0, agar mampu
Berapa jumlah host ID minimum yang diperlukan tiap toko. Apakah Jumlah tersebut dapat dipenuhi dengan subnet mask hasil perhitungan sebelumnya ? Jelaskan.
Minimum butuh 2 host ID per toko,
atau 2 host ID per subnet.
Karena tersisa 8 bit untuk host ID per
subnet, berarti jumlah ini sangat
Tuliskan solusi subnet mask tersebut dalam representasi biner. Tunjukkan bagian yang menandakan network ID,
Gambarkan topologi jaringan toko ABC hasil
rancangan anda tersebut berikut detil alamat IP nya.
Misal, 1 router kantor pusat beserta
servernya, dan beberapa router toko beserta PC nya. Cantumkan alamat IP yang relevan.
165.32.0.0/ 24
165.32.1.1 (R), 165.32.1.2 (H) pusat 165.32.2.1 (R), 165.32.2.2 (H) toko 1 165.32.3.1 (R), 165.32.3.2 (H) toko 2 ....
Limitations of
Classful Addressing and
Fixed-Length Subnet Masks
1. Wasted addresses. Only one subnet mask can be used for a net-work prefix
Limitations of
Classful Addressing and
Fixed-Length Subnet Masks (2)
Routing protocols such as RIP are unable to
transmit subnet masks or extended network prefix information along with network IDs and IP addresses
All routers, servers, and workstations within a
given network all have the same subnet mask,
Limitations of
Classful Addressing and
Fixed-Length Subnet Masks (3)
Subnets must be sized to accommodate the
largest required subnet within a given network ID, resulting in wasted host
addresses that cannot be recovered or used by other subnets.
We need solutions....
Classless addressing and Variable-length subnet
TCP/IP Network Design
1. Network design with Classfull IP
Addressing
2. Classless Addressing and
Variable-Length Subnet Masks
RFP 1009
RFP1009 specifies how a single
network ID can have different subnet
masks among its subnets.
Implementing VLSM
The routers on the network where VLSM is
implemented must be able to share sub-net masks and/or extended network prefixes with each router advertisement.
Routing protocols such as OSPF and IS-IS do this,
whereas RIP and IGRP do not.
RIPv2 (RFC 1388), added support for VLSM to RIPv1.
All routers supporting VLSM must support a longest
match routing algorithm.
The implemented network topology must match the
Route Aggregation with VLSM
Dipecah jadi 254 subnet Dipecah jadi 254 subnet
Subnetting
Contoh 1: VLSM
Alokasi network =
128.25.0.0/21
Tentukan alokasi subnetwork untuk :
a) Network A terdiri dari 31 PC
b) Network B terdiri dari 255 PC
c) Network C terdiri dari 100 PC
d) Network D terdiri dari 525 PC
Analisis alamat jaringan IP
128.25.0.0/21
Range network : 128.25.0.0/21 - 128.25.7.255/21
128.25.0.0 = 1000 0000 . 0001 1001 . 0000 0000. 0000 0000 128.25.7.255 = 1000 0000 . 0001 1001 . 0000 0111 . 1111 1111
/21 = 1111 1111 . 1111 1111 . 1111 1000 . 0000 0000
Tentukan kebutuhan subnet
Subnetwork A : 31 + 2 = 33 64 6 bit
Masking /26 atau 255.255.255.192
Subnetwork B : 255 + 2 = 257 512 9 bit
Masking /23 atau 255.255.254.0
Subnetwork C : 100 + 2 = 102 128 7 bit
Masking /25 atau 255.255.255.128
Subnetwork D : 525 + 2 = 527 1024 10 bit
Masking /22 atau 255.255.252.0
Subnetwork E : 10 + 2 = 12 16 4 bit
Urutkan dari masking terbesar ke terkecil!
D, B, C, A, E
Contoh 2: VLSM
Alokasi network =
192.168.0.0/20
Tentukan alokasi subnetwork untuk :
a) Network A terdiri dari 1000 PC
b) Network B terdiri dari 555 PC
c) Network C terdiri dari 320 PC
d) Network D terdiri dari 130 PC
e) Network E terdiri dari 750 PC
Tentukan kebutuhan subnet
Subnetwork A : 1000 + 2 = 1002 1024 10 bit
Masking /22 atau 255.255.252.0
Subnetwork B : 555 + 2 = 557 1024 10 bit
Masking /22 atau 255.255.255.0
Subnetwork C : 320 + 2 = 322 512 9 bit
Masking /23 atau 255.255.255.254
Subnetwork D : 130 + 2 = 132 256 8 bit
Masking /24 atau 255.255.255.0
Subnetwork E : 750 + 2 = 752 1024 10 bit
Masking /22 atau 255.255.252.0
Subnetwork F : 10 + 2 = 12 16 4 bit
Urutkan dari masking terbesar ke terkecil!
A, E,B,C,D,F
Range NW awal : 192.168.0.0/20 - 192.168.15.255/20 Subnetwork A (1024):192.168.0.0/22 -192.168.3.255/22
Classless Inter-Domain Routing
(CIDR)
CIDR
was announced in September
1993 and is documented in RFCs 1517,
1518, 1519, and 1520.
CIDR is also sometimes referred to as
Implementing CIDR
CIDR addresses are issued in blocks known
as CIDR blocks.
“The first octet” is meaningless in
determining how many subnets or host IDs can be defined for a given CIDR block.
The only factor that determines the capacity
of a CIDR block is the network prefix
Implementing CIDR
The net-work prefix issued by the Internet
authorities indicates the number of bits used for the major network ID.
These bits are reserved and cannot be used
by the end users for subnet IDs or host IDs.
For example, if a CIDR block were issued
with a network prefix of /18, that would imply that the first 18 bits from left to right were
Contoh 1: CIDR
Jawaban:
IP : 192.168.235.1/20
Alamat IP : 11000000.10101000.11101011.00000001 = 192.168.235.1
Subnetmask : 11111111.11111111.11110000.00000000 = 255.255.240.0
Maka :
NW ID : 11000000.10101000.11100000.00000000 = 192.168.224.0
Rng Host ID : 11000000.10101000.11100000.00000001 = 192.168.224.1/20 11000000.10101000.11100000.00000010 = 192.168.224.2/20
. .
. .
Review:
1. Apa tujuan VLSM?
2. Apa tujuan CIDR?
Terimakasih
