Monday, February 5, 2007
IP Addressing: One
Binary to decimal conversion
-----------------------------------
1000 0000 = 128
1100 0000 = 192
1110 0000 = 224
1111 0000 = 240
1111 1000 = 248
1111 1100 = 252
1111 1110 = 254
1111 1111 = 255
Hex to decimal conversion
------------------------------
A 10
B 11
C 12
D 13
E 14
F 15
Coversion:
----------------
128 64 32 16 8 4 2 1
192(128+64) 1 1 0 0 0 0 0 0
240(128+64+32+16) 1 1 1 1 0 0 0 0
** Put 1 in the corresponding places, else 0
IP Addressing:
-----------------
1)Numeric identifier assigned to each machine on the n/w
2)Designates the specific location of a device in the n/w
3)S/w add(logical add) hard coded in NIC
4)used for routing in n/w layer
5)32 bit
Terminilogy
-------------
1)bit(1/0)
2)byte(8bit)
3)Octet(8bits grouping)
N/W Address:
-----------------
Designation used in routing to send pkts to a remote n/w
All 0 in host part
e.g.: 10.0.0.0/172.16.0.0/192.168.0.0
Broadcast address:
---------------------
-Used by applications and hosts to send info to all nodes on a n/w
-All 1's in host part
-Routers will do bradcast only when it has an update in its routing table.
-e.g:
255.255.255.255: all n/w + all nodes
172.16.255.255: all subnets and hosts on n/w 172.16.0.0
10.255.255.255: broadcast to all subnets and hosts on n/w 10.0.0.0
** IP addressing : hierarchial
MAC: flat
3 methods:
-------------
-32 bits
@ Dotted decimal: 172.16.30.56
@ Binary: 10101100.********.********.********
@Hex: AC:10:1E:38
Classification:
---------------
ClassA: N.H.H.H
ClassB: N.N.H.H
ClasssC:N.N.N.H
ClassD:Multicast
ClassE: Reasearch
**Unicast/braodcast/multicast
ClassA:
---------
First bit of first byte n/w add must always be off(0)
i.e. 0XXX XXXX
0000 0000::: 0
0111 1111::: 127
(0-127)
ClassB:
----------
First bit of first byte n/w add must always be 1 Second bit always off(1) i.e.
1000 0000:::128
1011 1111:::191
(128-191)
ClassC:
----------
First 2 bits 1
3rd bit 0
i.e.
1100 0000:::192
1101 1111:::223
(192-223)
ClassD & E
-----------
(224-255)
224-239: ClassD: Multicast
240-255: ClassE (Reserved)
Reserved IP:
---------------
1) N/W add of all 0s (this n/w)
2) N/W add of all 1s (all n/w)
3) N/W 127.0.0.1 (reserved for loopback testing, allows the node to send a test pkt to itself without generating n/w traffic)
4) Node add of all 0s (n/w address)
5) Node address of all 1s(all nodes, 128.2.255.255 means all nodes on n/w 128.2(B))
6)Entire IP add set to all 0s (used by cisco router to designate the defaulr route)
7)Entire IP add set to all 1s (Broadcast to all nodes on the current n/w)
all 1s broadcast (limited broadcast)
255.255.255.255
Class A Address:
--------------
N.H.H.H
e.g: 49.22.102.70 (49:: n/w address, 22.102.70::node address)
@NW add of all 0's (0000 0000) is reaserved.
@Address 127 is reserved for diagnostic
i.e. we can use 1-126 to designate class A n/w
i.e Actual number of usuable class A n/w add=128-2=126
24 bits for node address
i.e 2^24=16777216 unique combinations
case 4 and case 5:: Actual number: 16777212
(A huge number)
Valid host IDs :
All host bit off:: n/w address:: 10.0.0.0
All host bit on:: broadcast address: 10.255.255.255
i.e between 10.0.0.1<=>10.255.255.254
Class B address:
-------------------
N.N.H.H
e.g: 172.16.30.56 (172.16:: n/w address; 30.56:: node address)
2^16 unique combinations of n/w address
but class B n/w address to start with 1/0, so 14 positions to play
i.e 2^14=16384 unique class B n/ws
Node: 2^16-2=65534 node address
valid host ID:
All host bit 0:: n/w address: 172.16.0.0
All host bit 1:: broadcast:: 172.16.255.255
i.e 172.16.0.1<=>172.16.255.254
ClassC address:
------------------
N.N.N.H
e.g:
192.168.100.102 (n/w address is 192.168.100; Node add:: 102 )
as first 3 bit portions are always 110
i.e 24-3=21:: 2^21=2097152 n/w
2^8-2=254 node address
valid host id:
192.168.100.1 <=> 192.168.108.254
Private IP address:
------------
can be used in a primvate n/w
not routable through internet
CLASS A: 10.0.0.0 _ 10.255.255.255
Class B: 172.16.0.0._ 172.31.255.255
Class C: 192.168.0.0 _ 192.168.255.255
Subnetting:
--------------
Subnet address:
----------------
@ Every machine on the network must know which part of host address will be used as subnet add. This is done by assigning a subnet mask to each machnie.
@32 bit value that allows the receipnt of the IP packet to distinguish the n/w ID portion of IP add from the host ID portion of IP address.
default:
A 255.0.0.0/8
B 255.255.0.0/16
C 255.255.255.0/24
e.g:
255.255.0.0/21
1111 1111.1111 1111.1111 1000.0000 0000
255.255.248.0
CIDR:Classless Inter-Domain Routing
---------------------------------------------------
CIDR is a new addressing scheme for the Internet which allows for more efficient allocation of IP addresses than the old Class A, B, and C address scheme
Why Do We Need CIDR?
------------------------
With a new network being connected to the Internet every 30 minutes the Internet was faced with two critical problems:
@Running out of IP addresses
@Running out of capacity in the global routing tables
Link to IP Addressing: Two
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