Cloud Workers

Cloud workers are managed SIP testing engines hosted and operated by CallMeter. They require no setup, no deployment, and no maintenance on your part. When you create a test and click Run, cloud workers are allocated automatically to execute your SIP endpoints.

Every CallMeter plan includes access to cloud workers, making them the fastest path from account creation to your first test results.

What "managed" means in practice:

• CallMeter provisions, monitors, and maintains the worker infrastructure
• Workers are automatically updated to the latest SIP engine version
• Capacity is scaled by CallMeter based on platform demand
• You interact with cloud workers only through test configuration --- selecting a region and running your test
• No Docker containers to deploy, no tokens to manage, no servers to maintain

How Cloud Workers Operate

When you start a test that targets cloud workers, the following happens:

1. Allocation --- CallMeter's scheduler examines available cloud worker capacity in your preferred region and allocates endpoint slots across one or more workers.
2. Execution --- Allocated workers register SIP accounts with your registrar, establish calls, transmit media, and collect quality metrics.
3. Reporting --- Metrics stream back to CallMeter in real time and appear in your dashboard as the test progresses.
4. Release --- When endpoints complete, their capacity slots are released back to the pool for other tests.

Cloud workers are shared infrastructure. Multiple organizations may use the same pool of workers, but each test run is fully isolated --- your SIP credentials, media streams, and metrics are never visible to other users.

Regions

When creating a test, you select the region your SIP traffic originates from. CallMeter currently operates cloud workers in one region:

Region matters for latency-sensitive tests: the shorter the network path between the worker and your SIP infrastructure, the more representative the results. If your SIP server is far from EU West, deploying your own worker close to it will give you a more accurate baseline than any cloud region would.

Cloud Capacity by Plan

Cloud worker capacity varies by plan: how many endpoints you can run at once. Your current limits are shown on the plans page in your dashboard.

The endpoint limit applies to concurrent usage rather than to a single test. You can run several tests at the same time, but their combined endpoint count cannot exceed your plan's limit.

What Cloud Workers Can Test

Cloud workers are fully capable SIP testing engines. There is no feature difference between cloud workers and user-owned workers in terms of testing capabilities. Both types support:

• All SIP transport protocols --- UDP, TCP, and TLS, plus AUTO for RFC 3263 DNS-based discovery
• All supported audio codecs --- PCMA, PCMU, G.722, Opus, G.726-32, GSM, Speex
• All supported video codecs --- H.264, VP8
• Custom media files --- Upload your own audio and video content for realistic call simulation
• Caller and callee modes --- Workers can initiate calls, receive calls, or both
• Group configurations --- Multiple groups of endpoints with different settings in the same test
• Full metric collection --- All 60+ VoIP quality metrics across SIP signaling, RTP transport, codec performance, call timing, and network behavior
• Probes --- Scheduled recurring tests with threshold-based alerting
• Multi-group tests --- Different groups targeting different codecs, media files, or call patterns within a single test run

The only difference between cloud and user-owned workers is where they run (CallMeter's infrastructure vs. yours) and what they can reach (public internet vs. your private network).

Best Practices for Cloud Workers

1. Mind the distance to your SIP infrastructure --- Cloud workers run in EU West, so a SIP server in Frankfurt is a short network path away and a SIP server on another continent is not. If distance is distorting your results, deploy your own worker next to the infrastructure you are testing.

2. Schedule large tests during off-peak hours --- If you are running high-endpoint-count tests on shared capacity, consider scheduling them outside business hours (UTC) to minimize contention.

3. Use probes for ongoing monitoring --- Cloud workers are excellent for continuous monitoring probes that run periodically against public-facing SIP endpoints.

4. Start with cloud, then add user-owned --- Begin testing with cloud workers to validate your test configuration. Once your tests are dialed in, deploy user-owned workers for private infrastructure testing.

5. Compare cloud vs. on-premise --- Use cloud workers alongside user-owned workers in the same test to measure external versus internal call quality.

Limitations of Cloud Workers

While cloud workers are powerful and convenient, they have inherent limitations:

Cannot Reach Private Infrastructure

Cloud workers run in CallMeter's infrastructure and can only reach SIP servers accessible from the public internet. If your PBX is behind a firewall, in a private VPC, or on an internal network, cloud workers cannot connect to it.

Workaround: Deploy user-owned workers inside your network.

Shared Capacity

Cloud workers serve multiple customers. While test isolation is complete, capacity is shared. During high-demand periods, you may experience:

• Slight delays before test execution begins
• Reduced maximum concurrent endpoints below your plan limit

Workaround: Deploy user-owned workers for guaranteed, dedicated capacity.

No Control Over Network Path

When using cloud workers, you cannot control the network path between the worker and your SIP infrastructure. Factors like internet routing, ISP peering, and geographic distance affect results.

Workaround: Deploy workers in your own datacenter or co-located with your SIP infrastructure for controlled network conditions.

Limited Geographic Options

Cloud workers are available in CallMeter-operated regions only. If you need to test from a specific location not covered by our regions (e.g., a particular office, datacenter, or country), cloud workers cannot fulfill that requirement.

Workaround: Deploy user-owned workers at the exact location you need.

SIP and RTP Traffic Traverses the Internet

All SIP signaling and RTP media between cloud workers and your SIP infrastructure travel over the public internet. For organizations with data residency or compliance requirements, this may be unacceptable.

Workaround: Deploy user-owned workers to keep all SIP/RTP traffic within your network boundary.

When Cloud Workers Are Sufficient

Cloud workers are the right choice for many common testing scenarios:

• SIP trunk testing --- Validate connectivity and quality to your SIP trunking provider
• Cloud PBX evaluation --- Test hosted PBX services, UCaaS platforms, and cloud-hosted telephony systems
• Codec comparison --- Compare audio and video quality across different codecs over real network conditions
• Baseline establishment --- Establish quality baselines for internet-facing SIP services
• Quick validation --- Run a fast test to verify that a SIP service is responding correctly after a change
• Probe monitoring --- Schedule recurring health checks against public SIP endpoints
• Load testing public infrastructure --- Stress test SIP servers designed to handle internet traffic

If all of the following are true, cloud workers will serve you well:

1. Your SIP infrastructure is reachable from the internet
2. You do not have data locality compliance requirements
3. Your concurrent endpoint needs fit within your plan
4. You do not require tests from a specific unlisted location

Dedicated Cloud Workers

For organizations that want the convenience of managed infrastructure with dedicated capacity, CallMeter offers dedicated cloud worker packages:

Three packages are offered -- Dedicated-1, Dedicated-3 and Dedicated-5 -- differing in how many dedicated workers they provision and therefore in total reserved endpoint capacity.

Dedicated packages are quoted rather than published: ask us or your account manager for the current figures. The number in each name is the number of workers the package provisions.

Dedicated cloud workers provide:

• Reserved capacity --- Your endpoints are guaranteed, no contention with other users
• Priority scheduling --- Tests start immediately without queuing
• Managed by CallMeter --- No Docker deployment or maintenance required
• Automatic updates --- Always running the latest SIP engine version

Contact support@callmeter.io or your account manager to add dedicated cloud workers to your plan.

When to Move Beyond Cloud Workers

Cloud workers are the starting point for most users, but there are clear signals that indicate it is time to deploy your own workers:

The transition costs you nothing. You can use cloud workers and user-owned workers in the same project, even in the same test. Different groups within a test can target different workers, allowing you to compare cloud-path quality against on-premise quality in a single run.

Monitoring Cloud Worker Usage

You can monitor cloud worker utilization from within the platform:

1. Navigate to your project's Workers page
2. Cloud workers appear with the label Cloud and their assigned region
3. During test execution, the Capacity Used column shows how many endpoints are currently allocated to your test

Cloud workers show status ONLINE when available and DRAINING when completing work. You do not see cloud workers in OFFLINE state --- they are managed transparently by the platform.

Cloud Workers and User-Owned Workers Together

A common and powerful pattern is to use both worker types simultaneously:

• Cloud workers test the external path --- how your SIP infrastructure performs when reached from the internet
• User-owned workers test the internal path --- how your SIP infrastructure performs from within your own network

By running both in a single test with different groups, you can directly compare external versus internal call quality. This helps identify whether quality issues originate in your infrastructure or in the network path between the internet and your SIP servers.

Next Steps

• Deploying Your Own Workers --- When cloud workers are not enough, deploy Docker workers in your infrastructure
• Capacity and Scaling --- Understand capacity limits and how to scale beyond them
• Plans and Pricing --- Compare plan tiers and their cloud worker allocations