Devices function at Layers

Teaching Topology

SUBNETTING The highly dreaded….

Subnetting Why Subnet? What You Need How to Subnet Example (ie Easy Example) Real Life (ie Hard Example)

Why Subnet? IP Address

Millions of Addresses Available –Over 16,000,000 Efficiency –Non-subnetted networks are wasteful –Division of networks not optimal Smaller Network –Easier to manage –Smaller broadcast domains Why Subnet?

What You Need Understand Address System Understand Classes of Networks “Two-Tums” Table –Formulas –Magic Numbers –Subnet Mask “ANDing” Process

Network is Different from MAC MAC (Media Access Control) Individual Machine Assigned at Factory NAME IP (Internet Protocol) Address Assigned by Central Body Classes May Change for Individual PC Network & Host ADDRESS: City & Street

What is an Address? _ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _ (Digital) (Decimal)

What is an Address? CLASS A: _ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _ CLASS B: _ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _ CLASS C: _ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _

Dissecting the Address > Classes < CLASS RANGES: –A: 0 – 127N. H. H. H –B: 128 – 191N. N. H. H –C: 192 – 223N. N. N. H _ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _ (Digital) (Decimal) CLASS B

TWO-TUMS MAGIC NUMBERS: SUBNET MASK:

Magic Formulas Number of Usable Subnets 2 n – = = = = = = = = 4 Number of Usable Hosts/Subnet 2 h-n – = = = = = = = = 4 n = # borrowed bits h = # bits available in host address

Subnet Mask What is a Subnet Mask? –“Extended Network Prefix” –Indicates extent of the Network numbers _ _ _ _ _ _ _ _ Why is it needed? –Used by router to determine Network Address How? –Uses “ANDing” to compare Mask to IP Address

ANDing Process MASK: IP: Network Address:

How to Subnet? * Subnet: Borrow _ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _._ _ _ _ _ _ _ _ (Digital) (Decimal)

Easy Example

Set Up Subnets Subnets What is the Subnet Mask? What are the Network Addresses? What is the Broadcast Domain What IP Addresses are available?

Steps…. 1.What is the CLASS? 2.How many BITS do we need to borrow? 3.Determine Subnet Mask 4.Determine “Magic Number” 5.Set up Table for IP Address (“Wire”), Range & Broadcast Domain 6.Fill in Table 1.C [Range: 192 – 223]] 2.5 Subnets 3 [ = 6] Use Subnet Mask # Borrow 3 Bits Wire Range BC 6.

Table WIRERANGEBC

Table WIRERANGEBC Class C Borrow 5 Bits

Table WIRERANGEBC Magic Number

Table WIRERANGEBC Subnet Mask

Table WIRERANGEBC

Table WIRERANGEBC Broadcast Domain

Table WIRERANGEBC

Table WIRERANGEBC – – – – – – –

Table WIRERANGEBC – – – – – – – Reserved for Network Addresses Reserved for Broadcast Addresses

Table WIRERANGEBC – – – – –

Set Up Subnets

Set Up Subnets What is the Subnet Mask? What are the Network Addresses? What is the Broadcast Domain What IP Addresses are available? * Needs 500 Subnets

Steps…. 1.What is the CLASS? 2.How many BITS do we need to borrow? 3.Determine Subnet Mask 4.Determine “Magic Number” 5.Set up Table for IP Address (“Wire”), Range & Broadcast Domain 6.Fill in Table 1.____ 2.____ Subnets ____ Borrowed Bits 3._____._____._____._____ Use Subnet Mask # Borrow Bits 4. _____

Table WIRERANGEBC