This hub covers the maths behind running networks and infrastructure: IPv4 subnetting, bandwidth and data budgets, storage arrays, and data-centre power, cooling and redundancy. It's used by sysadmins, network engineers, MSP techs and home-lab builders who need a fast sanity-check rather than a full design tool. The tricky part is matching units and layers to your actual question — bits versus bytes, a subnet's host count versus its usable range, or throughput ceilings set by latency and window size rather than raw link speed.
Subnetting and IP addressing
Start with the Subnet Mask Calculator to derive the mask, network and broadcast from a CIDR; use Subnet Hosts for the usable-host count and IP Range when you only need the first/last address of a block.
Bandwidth, data and download budgets
Convert link speeds with Mbps to MB/s, size a transfer with Download or Upload Time, and track a monthly quota with Data Usage, Data Cap or the Streaming estimator; VoIP Bandwidth covers concurrent call planning.
Throughput tuning and latency
When a fast link underperforms, check the Bandwidth-Delay Product and MTU/MSS for framing and window limits, use Network Latency for round-trip estimates, and Link Aggregation or Switch Port Utilisation when the bottleneck is the fabric.
Data-centre power, cooling and redundancy
Size the rack with Rack Power Draw, then UPS Runtime and Server Room Cooling for backup and heat load; PoE Power Budget and PoE Voltage Drop cover powering switches and endpoints over Ethernet.
Storage arrays and availability
Use RAID Capacity for usable space after parity and RAID IOPS for read/write performance under a chosen level; the Uptime / SLA calculator turns a nines target into allowable downtime.
Passwords and security
Generate a strong random secret with the Password Generator, then gauge its strength in bits with the Password Entropy calculator before settling on a policy.
