MPLS Bandwidth Plan Calculator

Work out mpls bandwidth plan instantly with clear inputs, formula shown and shareable results.

About MPLS Bandwidth Plan Calculator

In a hub-and-spoke MPLS design the hub circuit must carry the share of branch traffic destined for central services, discounted by how many branches are simultaneously busy. Sizing the hub at the sum of branch bandwidths is enormously wasteful; oversubscription of 3:1 to 5:1 is normal. Traffic that stays branch-to-branch is what any-to-any MPLS handles without hub capacity.

Formula

Hub sizing

aggregate branch = sites x per-site bandwidth; hub required = aggregate x hub share x simultaneity; oversubscription = aggregate / hub

Worked example

With the default values below, MPLS Bandwidth Plan Calculator returns Hub bandwidth required of 168.0. Change any input above and every figure here is recalculated in your browser.

Inputs used

Branch sitesminimum 1: 30
Bandwidth per branchminimum 0.001 Mbps: 20 Mbps
Share of branch traffic reaching the hubaccepts 0.1–100 %: 70 %
Share of branches busy at onceaccepts 0.1–100 %: 40 %

Results

Hub bandwidth required: 168.0 Mbps
Sum of branch bandwidths: 600.0 Mbps
Hub oversubscription ratio: 3.57 :1
Branch-to-branch traffic: 72.0 Mbps

Step by step

1Values used
2Hub sizing
3Hub bandwidth required= 168.0 Mbps
4Sum of branch bandwidths= 600.0 Mbps
5Hub oversubscription ratio= 3.57 :1
6Branch-to-branch traffic= 72.0 Mbps

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why not size the hub for full aggregate?

Because branches are never all at peak simultaneously. Statistical multiplexing is the entire economic basis of shared WAN services.

How does cloud migration change hub sizing?

It reverses the flow. Traffic goes to internet-hosted services rather than the data centre, which is why local internet breakout at branches has largely displaced hub backhaul.