IP Pool Size When You Run Ten Mobile Lines Instead of One

A question that comes up in every fleet planning conversation: if one line gives me a certain number of addresses, do ten lines give me ten times as many? The honest answer is no, not quite, and understanding why helps you size a fleet properly. A line draws addresses from the carrier's regional pool in its metro. Ten lines in the same metro on the same carrier draw from the same pool. This article gives realistic expectations, explains repeats, and shows a simple way to measure it yourself.

What a pool is here

When a line rotates, the SIM reconnects and the carrier assigns it a public address from the range it uses for that region. The range is the pool. It is the carrier's, not ours; we do not own addresses, we own the devices and SIMs that are handed addresses. The pool for a metro is large, typically many thousands of addresses across several blocks, but it is finite, regional and shared with every subscriber of that carrier in the area.

A line that never rotates sees one address for as long as the carrier keeps it, which is often hours and sometimes days. A line that rotates every ten minutes sees up to 144 addresses in a day, minus repeats. The pool does not change because you rotate more; you just sample it more often.

How many addresses one line sees

In practice a line that rotates a few times an hour collects new addresses quickly at first, then sees repeats more and more often as the month goes on. The exact count depends on the carrier, the metro, the time of day and the size of the pool the carrier uses there. We do not publish a single figure because it would be wrong for half the lines; measure it on your own line with the method below.

Two things make the count lower than the number of rotations. First, the carrier sometimes hands back the same address the SIM just released. Second, the carrier's assignment is not random across the whole pool; it favours blocks that are near the gateway the SIM is attached to, so a line tends to orbit a subset of the pool.

What ten lines add

Ten lines in the same metro on the same carrier draw from the same regional pool, so over time their address sets overlap. On any given minute, though, ten lines hold ten different addresses, which is the thing most teams actually need: ten accounts or ten clients each on their own address at the same time. Over a month, ten lines will together see more distinct addresses than one line, but less than ten times as many, because of the overlap.

To widen the set of addresses rather than deepen it, spread the lines. Ten lines across three carriers in the same metro draw from three pools with no overlap between carriers. Ten lines across several metros draw from several regional pools. A fleet planned for breadth looks like a grid of carriers and metros, not ten identical rows.

• Same carrier, same metro: ten simultaneous addresses, overlapping sets over time.
• Three carriers, same metro: three pools, no cross-carrier overlap.
• Several metros: several regional pools; state-level geolocation changes with the metro.

Repeats are normal

Teams sometimes report a repeat as a fault: a line rotated and came back with the address it had an hour ago, or two lines in the fleet held the same address a day apart. Both are expected. The pool is finite and the carrier recycles addresses. A repeat does not mean the two lines are linked, and it does not mean anything about the address has changed; it is the same shared crowd address it was before.

If an immediate repeat is inconvenient for a task, rotate again. Each rotation is a fresh assignment, and the second attempt almost always lands elsewhere.

Measuring it on your own fleet

The measurement is simple and worth doing once per metro and carrier you use. Pick a line, call its rotation link on a fixed interval, and after each rotation record the exit address from an IP lookup. Run it for a day. Count distinct addresses and count how many were repeats. Do the same on a second line in the same metro and compare the two sets. The size of the intersection is the overlap you can expect across the fleet.

Keep the interval sensible; a rotation every minute does not give you more pool, it gives you more repeats. Ten to fifteen minutes is a reasonable sampling interval for a measurement, and most real work rotates far less often than that.

1. Choose one line and note its carrier and metro from the dashboard row.
2. Call the rotation link every ten minutes and record the new exit address each time.
3. After a day, count distinct addresses and repeats.
4. Repeat on a second line in the same metro and compare the two sets.
5. Decide whether to add lines on another carrier or metro based on how much the sets overlap.

Sizing a fleet from the numbers

Most teams do not need the widest possible address set. They need enough separate lines that every account or client has its own address at the same moment, and they need those addresses to be consistent in state and carrier type. That is a count of simultaneous lines, which is simply how many things must run at once. The pool size matters only for work that wants many different addresses over time from one line, and for that, rotation on a schedule plus a second carrier is the practical answer.

Every line costs the list price, so adding a line is a decision about separation, not an attempt to buy addresses in bulk. If the measurement shows heavy overlap between two lines you intended for breadth, move one of them to another metro for free and measure again.

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