FAQ-IPV4's Netting# INTERVIEW PREP GUIDE ABOUT SUBNETTING & SUPERNETTING OF IPV4
'Practical term used in professional training'
🔹 What is subnetting ?
Subnetting is the process of dividing one large IPv4 network into multiple smaller logical networks called subnets.
🔹 Why is subnetting required ?
To improve IP address utilization, enhance security, reduce broadcast traffic, and organize networks efficiently.
🔹 Which classes are used for normal networking ?
Class A, B, and C.
🔹 What are the two parts of an IP address ?
Network ID & Host ID.
🔹 What is CIDR notation ?
Classless Inter-Domain Routing format written as /24, /16, /8.
🔹 What does /24 mean ?
It means 24 bits are used for the network portion.
🔹 What is a network address ?
The first IP in a subnet that identifies the subnet itself.
🔹 What is a broadcast address ?
The last IP in a subnet used to send data to all hosts in that subnet.
🔹 What is a host address ?
An IP address assigned to devices like PCs, servers, routers, etc.
🔹 Why do we subtract 2 in subnet calculation ?
Because one IP is reserved for network address and one for broadcast address.
🔹 What is the formula for host calculation ?
2ⁿ – 2 (where n = host bits).
🔹 What is the formula for number of subnets ?
2ⁿ (where n = borrowed bits).
🔹 What happens if subnet mask increases ?
Number of hosts decreases.
🔹 What happens if subnet mask decreases ?
Number of hosts increases.
🔹 What is a default subnet mask of Class A, B, C ?
255.0.0.0 255.255.0.0, 255.255.255.0.
🔹 What is subnet increment ?
The block size between subnet networks (Formula: 256 – subnet mask value).
🔹 What is supernetting and another name of it ?
Supernetting is combining multiple smaller networks into one larger network and another name is Route aggregation or route summarization.
🔹 Why is supernetting used ?
To reduce routing table size and improve routing efficiency.
🔹 What protocol supports supernetting ?
CIDR-based routing protocols like OSPF, EIGRP, BGP.
🔹 What is route summarization ?
Combining multiple routes into one summary route.
🔹 What is the main advantage of supernetting ?
Smaller routing tables and faster routing decisions.
🔹 What condition is required for supernetting ?
Networks must be contiguous and have the same prefix.
🔹 What does contiguous mean ?
IP networks must be sequential without gaps.
🔹 What is a supernet mask ?
A shorter prefix mask than original subnet masks. Example:Combining four /24 networks → /22.
🔹 What is the main difference between subnetting and supernetting ?
Subnetting divides networks; supernetting combines networks.
🔹 Can subnetting and supernetting be used together ?
Yes, in hierarchical network design.
🔹 How does subnetting improve performance ?
Reduces broadcast traffic.
🔹 Why is subnetting important for network security ?
It separates departments and limits broadcast domains.
🔹 What is the real-world example of subnetting ?
Dividing a company network into HR, Finance, IT departments.
