Splitting A Class C Network Into 4 Subnets

Uploaded on

Splitting A Class C Network Into 4 Subnets

Splitting A Class C Network Into 4 Subnets

More in: Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads


Total Views
On Slideshare
From Embeds
Number of Embeds



Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

    No notes for slide


  • 1. NAD710 - Introduction to Networks Using Linux Splitting a class C network into 4 subnets February 2,2001 Professor Tom Mavroidis
  • 2. Things to Remember
    • RFC950 - old rules, over 5 years old
    • Still used in some netware servers, if unsure about environment adhere to RFC950.
    • RFC1812 - new rules, simplifies networking, introduces CIDR (Classless Inter-Domain routing).
    • Suse 6.4 supports IPv4.
  • 3. Review-RFC950
    • An IP Address is broken up into three parts: the network portion, the subnet portion (optional), and the host portion. The size of the network portion is determined by the first byte of the address:
  • 4. Rules - RFC950
    • All hosts on the same subnet must agree on the subnet mask. Otherwise, packets actually intended for another subnet may never leave the existing subnet: a host won't give to the router a packet it thinks is destined for the local segment.
  • 5. Rules - RFC950
    • No two different subnets can include the same host address.
    • The top and bottom host numbers are reserved; the bottom one is shorthand for the whole subnet, and the top one is the broadcast address.
    • The bits in the subnet portion cannot be all ones
  • 6. Valid Subnet
    • Network is unique on either side of the Router. 192.168.1 + 192.168.2
  • 7. Invalid Network
    • Same Network resides on both sides of Router. 192.168.1
  • 8. or 11000000.10101000.00000001.00000001
    • Lets break this network down into 4 subnets
    • That means we need to borrow 2 bits from the host octet (byte).
    • Our default subnet mask is or 11111111.11111111.11111111.00000000
    • Borrowing 2 bytes gives us 128 + 64 = 192 or 11111111.11111111.11111111.11000000 or referred to as /26 or in dotted decimal notation
  • 9. List of networks for
    • The four networks we will get are
  • 10. Network Address Calculation
    • Binary and to get the network address
  • 11. Host Address
    • Invert the subnet and do a binary and again to get the host address
  • 12. Broadcast address
    • XOR to get the Broadcast address