Review:OSI vs TCP/IP

Review:Network vs Host

Agenda s/d UAS:

1. IP Addressing & Subnetting

2. Network Layer (1) : Routing algorithm

3. Network Layer (2) : IP

4. Transport Layer (1) : Flow control

5. Transport Layer (2) : TCP & UDP

6. Application Layer : DNS, Email, WWW

7. Network Security : Basic concept

Internet Protocol (IP)

IPv4 (32 bits) vs IPv6 (128 bits)

Packet routing, addressing, ID

The hardware : Router routing

Host ID

One router interface = a network

Two different NW (or more) can do communication using Router

See Simco visualization...

Chapter 8

Advanced TCP/IP

Network Design

IP Addressing

Classfull

Conventional/ Default/ Standard Net Mask

Sub Net Mask

Variable Length Subnet Mask (VLSM)

Classless

Classless Inter Domain Routing (CIDR)

Classful IP Addressing

There are three basic classes of addresses

known as class A, B, or C networks

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

IP address are known as the network prefix,

the net­work number, or the major network

Private IPv4 address spaces

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 hosts per network is too small for most organizations, while a Class B address with its limit of 65,534 hosts per subnet is too large.

Subnetting

Networks grew and needed to be divided or

segmented in order to improve traffic flow.

Routers join two separate net­works.

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

addresses.

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 for the subnet ID.

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 network prefix, subnet mask in binary and decimal, network ID, subnet ID, and host ID

Subnet Masks

Alternative Subnet masks for a Class B

network

Subnet DesignContoh kasus

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. Alamat IP yang dimiliki jaringan toko tersebut adalah 165.32.0.0.

Subnet DesignLangkah-langkah

1. Defining subnet numbers

2. Reserved Subnet Numbers

3. Defining Host Address for a Given Subnet

4. Reserved Host Address

5. Determining if IP Address are Part of the

Same Subnet

Subnet Design (1)

Network Prefix Subnet NumberReserved for

Host ID

Decimal with Extended/ Network

PrefixAssigned Network ID 10100101.00100000 00000000 00000000 165.32.0.0/16

Subnet 0 10100101.00100000 00000000 00000000 165.32.0.0/24

Subnet 1 10100101.00100000 00000001 00000000 165.32.1.0/24Subnet 2 10100101.00100000 00000010 00000000 165.32.2.0/24

... ... ... ... ...Subnet 254 10100101.00100000 11111110 00000000 165.32.254.0/24

Subnet 255 10100101.00100000 11111111 00000000 165.32.255.0/24

1. Defining Subnet Numbers

Subnet Design (2)

2. Reserved Subnet Number

• All zeros subnet

Subnet 0 (165.32.0.0/24) is identical to network ID 165.32.0.0/16

not compatible with classfull router so, it’s reserved

• All Ones subnet

The All Ones subnet ID for broadcasting to all subnets so, it’s

also reserved

Decimal with Extended/ Network Prefix

Assigned Network ID 165.32.0.0/16All-Zeros Subnet 165.32.0.0/24Broadcast 165.32.254.0/16All-Ones Subnet 165.32.255.0/24

Subnet Design (3)

3. Defining Host Address for a Given Subnet

• Consist of 254 Host ID (2 Host ID are reserved)

Extended Network Prefix Host ID DecimalHost 1 10100101.00100000.00000001 00000001 165.32.1.1/24Host 2 10100101.00100000.00000001 00000010 165.32.1.2/24Host 3 10100101.00100000.00000001 00000011 165.32.1.3/24Host 4 10100101.00100000.00000001 00000100 165.32.1.4/24Host 5 10100101.00100000.00000001 00000101 165.32.1.5/24Host 253 10100101.00100000.00000001 11111101 165.32.1.253/24Host 254 10100101.00100000.00000001 11111110 165.32.1.254/24

Defining Host IDs for a Given Subnet

(Subnet 1 165.32.1.0/24)

Subnet Design (4)

4. Reserved Host Address

• All zeros Host ID 165.32.1.0/24

• All Ones Host ID 165.32.1.255/24

Subnet Design (5)

5. Determining if IP Address are Part of the Same

Subnet

Example :

IP Address 192.210.165.13/ 29

First Octet Second Octet Third OctetSubnet Portion of Fourth Octet

Host ID Portion of Fourth Octet

192.210.165.13 11000000 11010010 10100101 00001 101255.255.255.248 11111111 11111111 11111111 11111 000Result Binary from logical AND

11000000 11010010 10100101 00001 101

Result Decimal 192 210 165 8 5

Network ID : 192.210.165.8/29

Host ID : 192.168.210.13/29

Review:

1. Jelaskan yang dimaksud dengan : Network ID, rentang IP host, dan IP broadcast, pada suatu IP address.

2. Untuk semua IP dibawah ini, sebutkan :

Kelasnya

Network ID, rentang IP Host, dan IP Broadcast nya.

175.175.59.95 175.175.50.99 175.175.99.50

195.175.59.95 195.175.50.99 195.175.99.50

20.20.20.2 180.180.180.2 200.200.200.2

20.20.20.1 180.180.180.1 200.200.200.1

Net mask yang digunakan sesuai kelas IP nya (classful IP)

Example :

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 :

NetWk ID : 11000000.10101000.11100000.00000000 = 192.168.224.0

Rng IP Host : 11000000.10101000.11100000.00000001 = 192.168.224.1/20

11000000.10101000.11100000.00000010 = 192.168.224.2/20

.

.

. .

11000000.10101000.11101111.11111101 = 192.168.239.253/20

11000000.10101000.11101111.11111110 = 192.168.239.254/20

Brdcst IP : 11000000.10101000.11101111.11111111 = 192.168.239.255

Limitations of Classful Addressing

and Fixed-Length Subnet Masks

1. Wasted addresses … only one subnet mask

can be used for a net­work prefix

2. A shrinking pool of available IPv4 addresses

Routing protocols such as RIP are unable to

transmit subnet masks or extended network

prefix information along with network IDs and

IP addresses

Limitations of Classful Addressing

and Fixed-Length Subnet Masks

All routers, servers, and workstations within a given network all have the same subnet mask,

A fixed subnet mask implies a fixed subnetsize for all subnets of a given network ID.

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.

Variable-Length Subnet Masks

Variable-Length Subnet Masks

RFP 1009

RFP1009 specifies how a single

network ID can have different subnet

masks among its subnets.

Minimizes the wasted IP addresses

forced by a single subnet mask per

network ID as defined by the original

RFC 950 Subnetting technique

Implementing VLSM

The routers on the network where VLSM is implemented must be able to share sub­net 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 distribution of addresses and definition of subnets

Route Aggregation with VLSM

SubnetConventional vs VLSM

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 supernetting.

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

assigned by the Internet authorities when the

CIDR block is issued.

Implementing CIDR

The net­work 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 reserved for the network ID and leave 14 bits (32–18) for subnet IDs and host IDs.

CIDR Block Capacity

Review:

1. Apa tujuan VLSM?

2. Apa tujuan CIDR?

3. Jelaskan perbedaan classful routing protocol dengan classles routing protocol.

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Jaringan-IP.pptx