Secure Egress Cost per GiB

APN vs SASE vs SD-WAN

Compare APN, Internet+SASE/ZTNA, and SD-WAN backhaul on a single normalized metric: secure egress $ / useful GiB (after tunnel/encryption overhead).

POCLAB TCO STUDIO · Network & Zero Trust Economics

Formula ($recurring + $usage + $egress) ÷ usefulGiB

Overhead includes tunnels, encryption, headers

Inputs by path

Enter payload GiB per month per path plus recurring and per-GiB costs.

Option A

Payload volume before overhead

GiB / month

Overhead tunnels, headers, loss

% of payload

Recurring monthly fees APN, head-end, licenses

$ / month

Carrier data rate $ / GiB rated

$ / GiB

Backhaul / egress MPLS, IXC, cloud

$ / GiB

Secure egress — $/GiB

Monthly: — Useful GiB: — Lost to overhead: —

Option B

Payload volume full-tunnel or split

GiB / month

Overhead TLS, full-tunnel

% of payload

Recurring monthly fees SASE + underlay

$ / month

Underlay data rate 5G / DIA / BB

$ / GiB

POP → app egress cloud egress / IX

$ / GiB

Secure egress — $/GiB

Monthly: — Useful GiB: — Lost to overhead: —

Option C

Payload volume before hairpins

GiB / month

Overhead double tunnels, QoS

% of payload

Recurring monthly fees SD-WAN licenses, hub

$ / month

Underlay data rate per GiB (both legs)

$ / GiB

DC / cloud egress final exit

$ / GiB

Secure egress — $/GiB

Monthly: — Useful GiB: — Lost to overhead: —

What this is calculating

1. You give monthly payload GiB before overhead plus all recurring and per-GiB costs for each path.

2. The tool derives useful GiB that reach the app after overhead, and the monthly total spend per path.

3. It then computes a normalized secure egress $/GiB for APN, SASE and SD-WAN and compares them.

Comparison

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OptionWaiting for inputs…

Lowest secure egress $/GiB

Option	$ / secure GiB	Monthly total	Useful vs payload
APN Option A	— secure egress $/GiB	— per month	— useful / payload
SASE Option B	— secure egress $/GiB	— per month	— useful / payload
SD-WAN Option C	— secure egress $/GiB	— per month	— useful / payload

How to use in a customer call:

Show how tunnel overhead taxes “unlimited” plans on each path.
Contrast APN vs SASE when traffic volume scales but endpoint count doesn’t.
Highlight when SD-WAN backhaul becomes a “hairpin tax” vs direct SASE egress.