Need some help troubleshooting intermittent 408 Request Timeout errors hitting the /api/v2/telephony/providers/edges endpoint during a burst load test. We are simulating 150 concurrent SIP trunk registration attempts using JMeter 5.6 from a Singapore-based instance to match our production latency profile. The initial 100 requests complete successfully with 200 OK responses, but once the thread count spikes above 120, roughly 30% of the subsequent requests fail with a 408 error after exactly 5 seconds. This is happening within the first minute of the ramp-up phase. We have verified that the SIP trunk credentials are correct and that the edge capacity in the Singapore region has available headroom according to the admin dashboard. The issue persists even when we reduce the concurrent threads to 80, suggesting it might not be a raw capacity limit but rather a connection handling bottleneck or a specific rate limiting behavior for registration bursts that isn’t documented clearly. We are using the default WebSocket keep-alive settings in our JMeter script. Has anyone seen this specific timeout pattern during SIP trunk provisioning under load? Any insights on whether we need to adjust the request interval or if this is a known platform API limitation for the Singapore edge? We are trying to finalize our capacity planning model and this inconsistency is making the results unreliable.
Have you tried adjusting the JMeter HTTP Request sampler’s timeout settings specifically for the Singapore region? The 408 Request Timeout often indicates that the client-side timeout is stricter than the server’s processing time during burst spikes, rather than a genuine server-side failure. Since you are hitting 120+ concurrent threads, the network latency from Singapore to the Genesys Cloud edge might be adding up with the API queueing time.
In JMeter, ensure the Connect Timeout and Response Timeout are set to at least 30000ms (30 seconds) to allow for the increased latency. Also, check if you are using the HTTP Request Defaults correctly to avoid repeating parameters.
Here is a recommended configuration snippet for the HTTP Request sampler:
<HTTPSamplerProxy guiclass="HttpTestSampleGui" testclass="HTTPSamplerProxy" testname="SIP Trunk Registration" enabled="true">
<elementProp name="HTTPsampler.Arguments" elementType="Arguments" guiclass="HTTPArgumentsPanel" testclass="Arguments" testname="User Defined Variables" enabled="true">
<collectionProp name="Arguments.arguments"/>
</elementProp>
<stringProp name="HTTPSampler.domain">api.mypurecloud.com</stringProp>
<stringProp name="HTTPSampler.port">443</stringProp>
<stringProp name="HTTPSampler.protocol">https</stringProp>
<stringProp name="HTTPSampler.path">/api/v2/telephony/providers/edges</stringProp>
<stringProp name="HTTPSampler.method">POST</stringProp>
<stringProp name="HTTPSampler.connect_timeout">30000</stringProp>
<stringProp name="HTTPSampler.response_timeout">30000</stringProp>
<boolProp name="HTTPSampler.follow_redirects">true</boolProp>
<boolProp name="HTTPSampler.auto_redirects">false</boolProp>
</HTTPSamplerProxy>
Also, verify if the Singapore endpoint has specific rate limits that differ from other regions. The documentation mentions that burst capacity can vary by edge location. Check the official API docs here: https://developer.mypurecloud.com/api/rest/v2/telephony/
If the timeouts persist, try reducing the concurrent threads to 100 and adding a 500ms constant timer between requests to smooth out the burst. This often helps in identifying if the issue is purely throughput-related or a configuration mismatch.
The root cause here is the strict latency expectations of the JMeter client colliding with the Genesys Cloud edge processing queue during high concurrency. Coming from a Zendesk migration background, I see similar timeouts when bulk-importing tickets via the API without proper pacing. Zendesk handles burst loads differently, often queuing requests internally, whereas Genesys Cloud’s SIP trunk registration endpoints are sensitive to immediate response windows.
The suggestion above to adjust Connect Timeout is spot on, but you also need to extend the Response Timeout significantly. In JMeter, set Connect Timeout to 5000 and Response Timeout to 15000 (or higher) in the HTTP Request Defaults. This gives the Singapore edge enough breathing room to process the 120+ concurrent threads without the client giving up prematurely.
Additionally, consider implementing a Constant Throughput Timer in JMeter. Instead of firing all requests at once, limit the throughput to roughly 50 requests per minute. This mimics a more realistic registration pattern and prevents the edge from hitting its rate limits, which might be contributing to the 408 errors. In Zendesk, we used to stagger API calls using exponential backoff; applying a similar logic here in your test script will likely stabilize the results.
Also, verify that your User-Agent string in JMeter isn’t being flagged by Genesys Cloud’s security policies. Sometimes, non-standard headers can cause unexpected delays or drops. Use the HTTP Header Manager to ensure you’re sending standard headers like Accept: application/json and Content-Type: application/json.
Finally, check the Genesys Cloud monitoring dashboard for any spikes in CPU or memory usage on the Singapore edge during the test. If the edge is overloaded, no amount of client-side timeout adjustment will help. You might need to scale your test infrastructure or reduce the concurrency further. This approach should help you get a clearer picture of the actual system performance rather than hitting artificial client-side limits.