Roaming: home routing vs local breakout
Two roaming architectures: send traffic home or exit near the device. What each changes in path, control, measurement and the rules that apply.
Home routing sends roaming traffic back to the home network; local breakout sends it to the internet from the visited network. Home routing centralizes policy and adds a return path. Local breakout shortens the path and distributes control and obligations. Choose the architecture before you compare latency.
Key facts
- Home routing sends roaming traffic back to a gateway in the home network; local breakout exits in the visited network.
- Home routing centralizes policy and adds a return path; local breakout shortens the path and multiplies local arrangements.
- Local breakout is an architecture, not a SIM type: 3GPP local breakout keeps the home subscription, while a local or multi-IMSI profile is a separate way to get a local exit.
- Neither architecture changes the speed of light; the distance floor applies to both.
After this module you can
- Describe where the user plane is anchored in each architecture.
- Explain what local breakout removes and what it leaves in place.
- Choose the question that decides the architecture before any latency comparison.
On this page
Home routing sends the traffic back
Home routing sends the user plane back to the home network. The visited network carries the radio and tunnels the session to a gateway in the home network, which assigns the address, applies policy and exits to the internet. The path is longer than the distance between the device and the content, and the extra length is the trombone.
Home routing centralizes control: one address pool, one policy, one logging point and one place to change the APN. That helps a fleet that must look the same in every market. It also puts the home gateway and the inter-operator link in the path of every session, so a fault there affects every device, wherever it is.
The subscription stays visibly foreign. The visited network sees a roaming subscriber, and the home network remains the anchor. That is a policy fact, not a performance one: the traffic still crosses the distance twice.
The tunnel is not one link. It crosses an interconnect between two operators, and the return path can be asymmetric. Each hop adds a small delay, and a congested interconnect adds a large one. That is why a home-routed path can be slower than the distance alone predicts.
Where the user plane is anchored
Home routed
- Handset
- Visited network
- Mobile core
- Home network
- PGW / UPF
- Internet
- Handset
- Visited network
- Mobile core
- Local breakout
- Internet
Text description
In the home-routed state, the device attaches to the visited network, and the session is tunnelled to the home network's gateway before it reaches the internet. In the local-breakout state, the device still authenticates against the home subscription, but the user plane exits through a gateway in the visited network. The home network keeps the subscription and the policy anchor in both states.
Local breakout exits near the device
Local breakout exits near the device. The visited network carries the radio and provides the gateway that assigns a local address and sends the traffic to the internet from that country. The device still authenticates against its home subscription; the user plane does not travel home.
The path is shorter, so the distance part of the delay falls. What does not change is the rest: the speed of light, the route between the local gateway and the destination, the queueing and the application's own round trips. Local breakout removes the trombone, not the physics.
Local breakout multiplies arrangements. Each market needs a configured gateway, a roaming agreement that permits the exit, and APN or policy settings that allow the visited-network gateway. The device keeps its home subscription. A local or multi-IMSI profile with a local identity is a separate alternative that also gives a local exit, plus the operational work behind it.
The address changes with the anchor. A home-routed device can carry an address from the home pool and resolve names through the home resolver, so a content network may send it to a distant cache. A local breakout gives it an address in the visited country, which changes how local services, allowlists and geo-checks see it.
The distance floor, on a log scale
40 ms
| Value | What it means |
|---|---|
| 10 ms | Regional path |
| 40 ms | Regional path |
| 130 ms | Intercontinental path |
| 400 ms | Queues or a long path |
Text description
The ruler runs from 1 ms to 1000 ms. Marks at 10, 40, 130 and 400 ms show same-metro, regional, intercontinental and long or queued paths. The 130 ms mark is the round-trip great-circle floor for the Mexico City–Shanghai pair at a 1.0 path factor. The tool below applies the scenario's 1.5 path factor, which raises the floor. A measured round trip includes the route and the equipment, so it is always higher.
What changes and what does not
The path changes. Home routing adds a return leg between the visited network and the home gateway. Local breakout removes that leg and exits in the visited country. The size of the change depends on where the destination is, not on the name of the architecture.
Control changes. Home routing keeps the address pool, the policy, the logging and the APN in one place. Local breakout distributes them across markets, so each market needs its own configuration and its own operational owner. Central control is simpler to run; local control is closer to the traffic.
Measurement does not change. In both architectures, measure the round trip from the device to the destination the application uses, at the busy hour, and record the route. A public speed test measures a different path and cannot tell you which architecture is in place.
The regulatory question does not change either, but the answer may. The anchoring point decides which market sees the traffic and which rules may apply. A local exit can bring local registration, retention or lawful-intercept obligations into scope; a home-routed subscription can look like permanent roaming. The rule is per market and changes, so confirm it in writing with counsel.
Choose the architecture before the number
Choose from the application and the market, not from a general preference. A video call, remote control or point-of-sale authorization that keeps a person waiting is sensitive to the extra round trip. A fleet that sends everything to one home-hosted platform may prefer the single policy point.
Do not compare a home-routed latency with a local breakout latency unless the source, the destination and the measurement window are the same. A single ping to a public endpoint in another country measures that endpoint, not the architecture. Compare the anchor, the route and the round trip together.
Write down the anchor point, the APN, the address pool and the market rule for each fleet. A mix is normal. An undocumented mix is the problem: the next person cannot tell which device uses which path, and a change in one market breaks an assumption in another.
Test both paths with the transaction the application actually performs. A login, a payment authorization and a video frame have different round-trip counts. A ping to a public endpoint is a starting point, not the answer, because it does not exercise the application or the policy on the gateway.
Check your understanding
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A device in Brazil talks to a server in Germany: which path is it on, and how would you know?
It can be on either. Check the egress address and the route: an address from the home gateway in Germany points to home routing; an address from the visited gateway in Brazil points to local breakout. The APN policy and a traceroute confirm it.
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What does local breakout change, and what does it not change?
It removes the return leg to the home network and can shorten the path. It does not change the speed of light, the route to the destination, the queueing or the need for a local agreement.
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Which question do you ask before choosing?
Where is the destination, what does one extra round trip do to the application, and which market's rules apply to the traffic? The architecture follows those answers.
Answers are revealed on request. Nothing is scored, stored or sent.
FAQ
Which is faster?
Does local breakout need a local SIM?
Can we mix the two?
Terms you'll meet
Related
- Permanent roaming, country by country
How long a foreign SIM may roam before it needs a local profile, for Brazil, Mexico and Colombia, with the decision path to the right product.
- SGP.32 for IoT devices
What SGP.32 changes for IoT fleets, which devices qualify, and why SGP.02 devices cannot be upgraded over the air.
- eUICC identifier (EID)
The eUICC identifier, separate from the subscription.
Related products
Put this to work
Tell us the traffic, the destination and the measurement you need; we reply with the next step.