Posted on April 18th, 2009 by linux
Network Bits: 16
Network bits available ( x ):10xxxxxx xxxxxxxx hosts hosts this leave us with 14 bits designated to the number of networks. Since there are two possible bits to play with ( 1 or 0 ) the range of network is 2^14 = 16384. We need to subtract broadcast and network ID and the number of networks available is 16382.
RANGE: 10000000 - 10111111 -> 128 -191
Hosts:The number of available hosts can be calculated from a remaining 16 host bits. 2^16 = 65,536 subtract network ID and broadcast adress and this gives us 65,534 hosts available for CLASS B Network.
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Posted on April 18th, 2009 by linux
CLASS A RANGE:
Network bits available ( x ): 0xxxxxx
Networks: 8 bits. First bit from the network must by 0 so it give us 7 bits to play with. The number of networks which can be created is therefore 2^7 which is 128. However IP address 0.0.0.0 is used as a default gateway and 127.0.0.1 is used as a loop back. Therefore, we need to subtract those 2 addresses which gives as 126:
NETWORKS RANGE: 1- 126
Hosts: 24 bits ( 3 bytes ) can create 2^24 = 16,777,216 hosts in the single network. However we can not use a IP address of all host bits turned off for example 10.0.0.0 which is a network ID and furthermore we can not use a address which has all hosts bits turned on for example 10.255.255.255 which is a broadcast address. So the valid range for class a hosts is ( ( 2^24 ) -2 ) = 16,777,214
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Posted on April 18th, 2009 by linux
The following Internet layer protocols are required to remember for a ccna exams:
- IP ( Internet Protocol ): IP is a connectionless protocol and provides network address ( IP address ) and routing via internetwork.
- ARP ( Address Resolution Protocol ): This protocol resolves a hardware address ( Media Access Control - MAC ) to an IP address.
- RARP ( Reverse Address Resolution Protocol ): This protocol does exact opposite of ARP. It resolves a IP address from hardware address ( MAC )
- ICMP ( Internet Control Message Protocol ): This protocol provides a network troubleshooting messages such us “Destination Unreachable”.
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