Network Engineering

Outbound Bandwidth & Egress Transfer Calculator

Estimate monthly gigabytes transferred and required network uplink speeds based on email volume and payload size.

Monthly Egress Transfer
275 GB
Total data over the wire
Peak Required Bandwidth
101.8 Mbps
Sustained wire throughput
Recommended Port Uplink
Standard on all AutoSMTP nodes
Cloud Egress Cost (AWS SES/EC2)
$24.75 / mo
$0 in AutoSMTP (Included Unmetered)
Network Uplink Recommendation
For dispatching 5,000,000 emails/month with a 55 KB payload within a 6-hour daily window, a dedicated 1 Gbps unmetered port provides more than 9x headroom over peak requirements (101.8 Mbps), eliminating TCP queue latency.
Get 1 Gbps Unmetered Dedicated Outbound Uplink
Every AutoSMTP cluster includes unmetered 1 Gbps to 10 Gbps enterprise uplinks.
Deploy Dedicated MTA →

Network Architecture & MIME Payload Optimization

Email network overhead isn’t just HTML body text. Base64 encoded attachments, inline images, and multi-part MIME headers expand raw data transfer by 33% over wire protocols.

Base64 Expansion Factor
Binary images and files encoded into standard email bodies expand by approximately 1.33x in byte size. Always host heavy media on external CDNs rather than embedding inline attachments.
Cloud Egress Surcharges
AWS, Google Cloud, and Azure bill between $0.08 and $0.12 per gigabyte of outbound internet transfer. On dedicated bare-metal infrastructure, all bandwidth is unmetered.
TCP Window Scaling (RFC 1323)
Enable net.ipv4.tcp_window_scaling = 1 in Linux sysctl to maximize throughput across trans-continental SMTP hops without artificial latency bottlenecks.