What does /30 means in Networking?

Question

Please try give me an answer for networking and explain how many host can I get from /30

Answer 1

In networking, /30 is a CIDR (Classless Inter-Domain Routing) notation that indicates the subnet mask and the number of usable IP addresses within a subnet.

Subnet Mask for /30

1. A /30 subnet uses 30 bits for the network portion and 2 bits for the host portion.
2. This results in a subnet mask of 255.255.255.252.
3. In binary: 11111111.11111111.11111111.11111100

How Many Hosts Can You Have?

To calculate the number of usable hosts, use the formula:

2^n - 2, where n is the number of bits for the host portion.

1. For a /30 subnet, n = 2
2. So, 2^2 - 2 = 2 usable host IP addresses

This means a /30 subnet provides 4 total IP addresses:

1. 1 Network address
2. 2 Usable host addresses
3. 1 Broadcast address

Summary Table

CIDRSubnet MaskTotal IPsUsable HostsTypical Use
/30	255.255.255.252	4	2	Point-to-point connections between routers