Understanding QCI
What is QCI?
QCI (QoS Class Identifier) is a technical value used in LTE/4G/5G networks that helps mobile operators prioritize traffic. For example, voice traffic typically receives a higher priority than regular data.
In local SIMs, operators may assign different QCI values depending on the plan or use case — e.g., business vs. consumer traffic.
Does Simbase limit or deprioritize traffic?
No. Simbase does not apply throttling or artificial prioritization restrictions on your SIM card.
Our SIMs are standard roaming SIMs — not limited “IoT-only” variants.
They can initiate emergency calls, and behave like any international SIM used by frequent travelers or global businesses.
We provide full access to available 2G, 3G, 4G, and 5G bearer types, where supported by the network, and strive for multi network support for all countries.
You’re getting direct access to the radio network, just like any other SIM.
Why are QCI values irrelevant in a roaming setup?
When a device roams on a foreign network:
The visited carrier applies its own policies and overrides many values signaled by the home network.
The home operator (in this case, Simbase) cannot enforce or expose QCI values per carrier.
No roaming provider — not even the largest ones — can provide a complete list of QCI values per network.
Even if available, QCI is not a reliable indicator of real-world performance, especially for data-heavy applications.
Why might a native SIM feel faster?
In some cases, a native SIM from Verizon, AT&T, or T-Mobile may:
Break out to the internet locally (e.g., California → California), reducing latency.
Have guaranteed bandwidth or SLA-based prioritization.
Benefit from carrier-specific optimizations for local devices.
Simbase SIMs, like all roaming SIMs, break out in globally distributed locations(e.g., Virginia, USA, Dallas, USA, Frankfurt, DE, Sydney, AU) and rely on IP tunneling back to that location. This can increase latency slightly in some regions.
So what’s the best use case for Simbase SIMs?
Simbase SIMs are designed for resilient global connectivity where broad coverage, commercial flexibility, and independent network selection are key.
They are particularly suited for applications that:
Can tolerate latency in the range of ~100–250ms
Require redundancy across multiple networks in the same country
Need IP breakout consistency for logging, security, or compliance reasons
Are not dependent on carrier-specific QoS (QCI) agreements
Why is multi-carrier access better?
Unlike local SIMs which lock you into a single operator, Simbase SIMs can:
Dynamically select from multiple carriers per country based on signal strength and availability
Avoid local outages or congested towers by switching networks
Operate with broader radio technology support (2G, 3G, 4G, 5G, LTE-M, NB-IoT) depending on the SIM profile and device
This results in:
Better geographical coverage
Improved network reliability
A smoother roaming experience for mobile and stationary devices alike
What are the technical trade-offs?
Latency
100–250ms (IP breakout remote)
20–80ms (local breakout)
Bandwidth
Depends on local network load; no artificial throttling
May have higher burst throughput
QCI / QoS control
Not exposed or guaranteed (roaming)
Possible (carrier-specific)
Network access per country
Multiple carriers
Single carrier only
IP breakout location
Centralized (e.g., Virginia, USA)
Local
Failover / redundancy
✅ Built-in via multi-IMSI & carrier support
❌ Limited to one carrier
Summary
If your application can tolerate the normal roaming characteristics of non-local breakout and does not depend on guaranteed per-carrier QoS, Simbase offers a highly flexible, scalable solution with excellent coverage and global reach — without compromising bandwidth or reliability.
For latency-sensitive, region-locked, or QoS-guaranteed requirements, a native SIM may be more appropriate — but for everything else, Simbase gives you global control without local constraints.
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