1. Chabot College
ELEC 99.05
Why Subnet?

2. Why Subnet?
Security / Access control
Broadcast control
WAN links

3. Security / Access Control
Given one class C network,
3 subnets allow access rules to be different for each workgroup:
Senior Managerment subnet
Sales subnet
Engineering subnet

4. Security / Access Control
Access Rules:
Engineering & Sales can’t access Sr. Management subnet.
Senior Management subnet
Sales subnet
Engineering subnet

5. Security / Access Control
Access Rules:
All departments can access Intenet
Senior Management subnet
Sales subnet
Engineering subnet

6. Broadcast Control Given the class C network: 200.35.15.0 /24
3 subnets connected by a router
3 small broadcast domains
/27 subnet
/27 subnet
/27 subnet

7. WAN Links Given one class C network: 200.35.15.0 /24 No subnets.
WAN link uses up the only network.
(One IP address on each end of WAN link.)
No networks available for other segments:
Headquarters
Branch Office
/24 net

8. WAN Links Given one class C network: 200.35.15.0 /24 Subnet /27
WAN link uses only one of several available subnets:
Headquarters
Branch Office
/27 subnet
/27 subnet
/27 subnet
/27 subnet