@vishmithathejan154 wrote:
Can you help me by using example? Only if you can. So I can learn...
Sure, although this is now going to overlap with others' replies.
Networks are binary multiple sizes, i.e:
1 = /32
2 = /31
4 = /30
8 = /29
...
256 = /24
and so on.
Addresses, for any particular network, must start on a multiple of that size, for example, given the addresses 0 through 7, a /32 can be any of those; a /31 must be 0, 2, 4, 6; a /30 must be 0 or 4; a /29 can only be 0.
If you allocate any network, it cannot be part of a larger network that would encompass the same address(es). So, for example, if you allocate the /29 for 0..7, you can not allocate any of the smaller networks within 0..7 or conversely, if you allocate any smaller network from 0..7, you cannot use the /29 that uses them.
As network allocations require specific boundaries, you cannot always just allocate the next starting address to a larger address block.
For example, if you allocate 0 and 1 to a /31, you cannot allocate the next starting address, 2, to a /30, because it must start with a multiple of 4. Yet you could allocate 2 and 3 to a /31, and then allocate the next starting address, 4, to the /30, because 4 is a multiple of 4.
You likely know, the first address and last address are not used for host addresses. /31s can be used for p2p links, and /32s can be used both as a host address or network.
Also confusing, 192.168.1.0..7/29 addresses are all within the 192.168.1.0/29 network.
What I wrote about 0..7 can be repeated for 8..15, although now we can have 0..15 as a /28 network.
If VLAN 10 is to support just two users, it would normally, minimally, be assigned a /30 (as @Flavio Miranda showed), addresses 0..3 (2 hosts), but you could use the larger /29, addresses 0..7 (6 hosts).
If VLAN 20 is to support 10 users, it would normally, minimally, be assigned a /28 (14 hosts), but it must start on a multiple of 16, i.e. it cannot start directly after the foregoing /30 or /29, i.e. with either .4 or .8, so it would be 16..31.
To proceed with your other VLAN allocations, you need to understand VLAN 10 and VLAN 20 allocations.
BTW, whether VLAN 10 is allocated as a /30 or /29, it will leave some unused address space between it and VLAN 20's /28. That unused space could be allocated to support other small VLANs, as either /30 (V10), /30, /29, /28 (V20) or /30 (V10), /30, /30, /30, /28 (V20) or /29 (V10), /29, /28 (V20) or /29 (V10), /30, /30, /28 (V20).
