Quick Field Scenarios & Technical Cheat Sheets
Direct calculations, precise engineering metrics, and copyable configurations for CIDR Subnetting, MikroTik PCC Multi-WAN, CCTV NVR Storage, GPON FTTH Fiber Loss, and ZFS RAID Storage.
/32 Subnet Mask (255.255.255.255): Usable Hosts (1), Wildcard & IPv4 Range
Instant /32 CIDR reference: Subnet Mask is 255.255.255.255, Wildcard 0.0.0.0, Total IPs 1, and 1 Usable Hosts. Ideal for OSPF/BGP Router Loopback & Single Host Route.
/30 Subnet Mask (255.255.255.252): Usable Hosts (2), Wildcard & IPv4 Range
Instant /30 CIDR reference: Subnet Mask is 255.255.255.252, Wildcard 0.0.0.3, Total IPs 4, and 2 Usable Hosts. Ideal for Point-to-Point Inter-Router WAN Link (2 Usable IPs).
/29 Subnet Mask (255.255.255.248): Usable Hosts (6), Wildcard & IPv4 Range
Instant /29 CIDR reference: Subnet Mask is 255.255.255.248, Wildcard 0.0.0.7, Total IPs 8, and 6 Usable Hosts. Ideal for DMZ Public Server Sub-Block & BGP Peering (6 Hosts).
/28 Subnet Mask (255.255.255.240): Usable Hosts (14), Wildcard & IPv4 Range
Instant /28 CIDR reference: Subnet Mask is 255.255.255.240, Wildcard 0.0.0.15, Total IPs 16, and 14 Usable Hosts. Ideal for Small Branch Office & Switch Management VLAN (14 Hosts).
/27 Subnet Mask (255.255.255.224): Usable Hosts (30), Wildcard & IPv4 Range
Instant /27 CIDR reference: Subnet Mask is 255.255.255.224, Wildcard 0.0.0.31, Total IPs 32, and 30 Usable Hosts. Ideal for Department VLAN & PoE IP Camera Segment (30 Hosts).
/26 Subnet Mask (255.255.255.192): Usable Hosts (62), Wildcard & IPv4 Range
Instant /26 CIDR reference: Subnet Mask is 255.255.255.192, Wildcard 0.0.0.63, Total IPs 64, and 62 Usable Hosts. Ideal for 50-PC Computer Lab & Classroom VLAN (62 Hosts).
/25 Subnet Mask (255.255.255.128): Usable Hosts (126), Wildcard & IPv4 Range
Instant /25 CIDR reference: Subnet Mask is 255.255.255.128, Wildcard 0.0.0.127, Total IPs 128, and 126 Usable Hosts. Ideal for Building Floor LAN & Mid-Size Office Wi-Fi (126 Hosts).
/24 Subnet Mask (255.255.255.0): Usable Hosts (254), Wildcard & IPv4 Range
Instant /24 CIDR reference: Subnet Mask is 255.255.255.0, Wildcard 0.0.0.255, Total IPs 256, and 254 Usable Hosts. Ideal for Standard Office LAN & MikroTik Hotspot (254 Hosts).
/23 Subnet Mask (255.255.254.0): Usable Hosts (510), Wildcard & IPv4 Range
Instant /23 CIDR reference: Subnet Mask is 255.255.254.0, Wildcard 0.0.1.255, Total IPs 512, and 510 Usable Hosts. Ideal for Hotel/Campus Hotspot & Dual /24 Supernet (510 Hosts).
/22 Subnet Mask (255.255.252.0): Usable Hosts (1,022), Wildcard & IPv4 Range
Instant /22 CIDR reference: Subnet Mask is 255.255.252.0, Wildcard 0.0.3.255, Total IPs 1,024, and 1,022 Usable Hosts. Ideal for 1,000-User Campus Wi-Fi Supernet (1,022 Hosts).
/21 Subnet Mask (255.255.248.0): Usable Hosts (2,046), Wildcard & IPv4 Range
Instant /21 CIDR reference: Subnet Mask is 255.255.248.0, Wildcard 0.0.7.255, Total IPs 2,048, and 2,046 Usable Hosts. Ideal for ISP PPPoE Subscriber Pool & CGNAT (2,046 Hosts).
/20 Subnet Mask (255.255.240.0): Usable Hosts (4,094), Wildcard & IPv4 Range
Instant /20 CIDR reference: Subnet Mask is 255.255.240.0, Wildcard 0.0.15.255, Total IPs 4,096, and 4,094 Usable Hosts. Ideal for Large Enterprise & Data Center Fabric (4,094 Hosts).
MikroTik Dual-WAN (2 ISP) PCC Load Balancing & Failover Script for RouterOS v7
Production-ready MikroTik RouterOS v7 2-WAN PCC Load Balancing script with FIB routing tables, mangle rules, and recursive gateway failover.
MikroTik 3-WAN (Triple ISP) PCC Load Balancing Script for RouterOS v7
Complete 3-WAN PCC Load Balancing and failover configuration for MikroTik RouterOS v7.
16-Camera CCTV Hard Drive Storage for 30 Days 24/7 Recording (H.265 vs H.264)
How much HDD storage do 16 1080p CCTV cameras need for 30 days 24/7? Compare H.265 (~4.2 TB) vs H.264 (~8.4 TB) NVR requirements.
8-Camera CCTV Hard Drive Size for 30 Days 24/7 Recording
Calculate exact HDD size for 8 CCTV cameras recording 30 days 24/7. Requires ~2.1 TB with H.265 (use a 4 TB HDD).
GPON / EPON PLC Optical Splitter Loss Table (1:2, 1:4, 1:8, 1:16, 1:32) & FTTH Power Budget
Complete PLC optical splitter insertion loss chart: 1:2 (3.7 dB), 1:4 (7.3 dB), 1:8 (10.5 dB), 1:16 (13.8 dB) for GPON/EPON FTTH networks.
4x 4TB ZFS RAIDZ1 / RAIDZ2 & RAID 5 Usable Capacity Calculator
Calculate exact usable storage for 4x 4TB drives (16TB raw) in RAID 5 / RAIDZ1 (12 TB) and RAID 6 / RAIDZ2 (8 TB) on Proxmox VE.