VOS3000 SIP Response Codes CDR Complete 30-Plus Important Code Reference

VOS3000 SIP Response Codes CDR Complete 30-Plus Code Reference

Understanding VOS3000 SIP response codes CDR data is fundamental for any VoIP operator who needs to diagnose call failures, optimize routing, and maintain high call completion rates. SIP response codes are 3-digit status indicators defined in RFC 3261 that every SIP element generates during call signaling. VOS3000 records the final SIP response code in each CDR, providing a direct view into why calls succeeded or failed at the protocol level. This reference covers all 30+ SIP response codes you will encounter in VOS3000 CDRs, organized by class with troubleshooting guidance for each. Need help analyzing your CDR data? Contact us on WhatsApp: +8801911119966.

SIP response codes follow a class-based structure where the first digit indicates the response category. VOS3000 CDRs capture the final SIP response that determined the call outcome — for successful calls this is typically 200 OK, while failed calls record the error response that caused termination. By analyzing the distribution of SIP response codes across your CDR data, you can identify routing problems, capacity issues, and configuration errors that affect your ASR and revenue.

Table of ContentsVOS3000 SIP Response Codes CDR Complete 30-Plus Code ReferenceSIP Response Code Classes Overview4xx Client Error Codes in VOS3000 CDRs5xx Server Error Codes in VOS3000 CDRs6xx Global Failure CodesSIP Response Codes and ASR CorrelationRelated ResourcesFrequently Asked Questions About VOS3000 SIP Response Codes CDRWhat SIP response code indicates a successful call in VOS3000?What does SIP 503 Service Unavailable mean in my CDRs?How do I reduce 408 Request Timeout errors?Why am I seeing 403 Forbidden in my H.323 gateway CDRs?What is the difference between 486 Busy and 600 Busy Everywhere?Can I change how VOS3000 handles specific SIP response codes?Get Expert VOS3000 CDR Analysis Support Need Professional VOS3000 Setup Support?

SIP Response Code Classes Overview

The six SIP response code classes each represent a different category of signaling outcome. Understanding the class structure is the first step in interpreting VOS3000 SIP response codes CDR data efficiently.

ClassCategoryMeaningCDR Impact1xxProvisionalCall in progress, not finalRarely recorded as final CDR code2xxSuccessCall successfully establishedBillable call — 200 OK most common3xxRedirectionCall redirected to another URIMay or may not result in billable call4xxClient ErrorRequest failed due to client issueNon-billable — configuration or routing problem5xxServer ErrorServer failed to fulfill requestNon-billable — upstream or capacity issue6xxGlobal FailureCall rejected at all locationsNon-billable — should stop failover

4xx Client Error Codes in VOS3000 CDRs

4xx response codes indicate that the request contained bad syntax or could not be fulfilled at the client side. These are the most actionable codes because they often point to configuration problems that operators can fix directly.

CodeNameCommon Cause in VOS3000Resolution400Bad RequestMalformed SIP message from VOS3000Check SIP header settings and dial plan401UnauthorizedAuthentication credential mismatchVerify username/password on gateway403ForbiddenIP not authorized, account blockedCheck IP whitelist, account status404Not FoundDialed number not routableAdd prefix to routing table407Proxy Auth RequiredOutbound proxy requires authenticationConfigure proxy auth credentials408Request TimeoutNo response from gateway within timeoutCheck gateway availability and network480Temporarily UnavailableCallee offline or DND activeCheck callee registration status486Busy HereCallee line is busyNormal — enable busy stop switch487Request TerminatedCall cancelled by originatorCheck for early hangup or timeout

5xx Server Error Codes in VOS3000 CDRs

5xx codes indicate that the server side failed to process the request. These are often outside your direct control but understanding them helps identify which upstream carriers are experiencing problems. For more on failover behavior, see our VOS3000 call routing guide.

CodeNameMeaningAction500Server Internal ErrorGateway encountered unexpected errorContact gateway vendor or check logs502Bad GatewayUpstream gateway returned invalid responseCheck upstream gateway health503Service UnavailableGateway overloaded or in maintenanceRoute to alternate gateway504Server TimeoutNo response from upstream serverCheck network path to upstream

6xx Global Failure Codes

6xx response codes are global failures that indicate the call should not be retried at any other location. When VOS3000 receives a 6xx response, it should stop failover switching and record the code in the CDR. Understanding these codes helps prevent unnecessary gateway switching. For failover configuration, see our VOS3000 routing optimization guide. For assistance, message us on WhatsApp: +8801911119966.

CodeNameMeaningFailover Behavior600Busy EverywhereAll locations report busyStop switching603DeclineCall explicitly rejectedStop switching604Does Not Exist AnywhereNumber does not exist globallyStop switching606Not AcceptableSession description not acceptableCheck codec negotiation

SIP Response Codes and ASR Correlation

Analyzing VOS3000 SIP response codes CDR data alongside ASR metrics reveals which response codes are dragging down your call completion rates. A healthy deployment should show 200 OK dominating the CDR distribution, with error codes representing a small percentage of total calls.

Response Code DistributionHealthy ASRDegraded ASR200 OKAbove 70%Below 50%4xx errors totalBelow 15%Above 30%5xx errors totalBelow 10%Above 20%486 BusyBelow 10%Above 20%

Related Resources

VOS3000 Call Routing Guide

VOS3000 Routing Optimization

VOS3000 SIP Authentication

RFC 3261 – SIP Protocol Specification

Frequently Asked Questions About VOS3000 SIP Response Codes CDR

What SIP response code indicates a successful call in VOS3000?

In VOS3000 CDRs, a SIP 200 OK response code indicates that the call was successfully established and answered. This is the standard success response defined in RFC 3261 that confirms the INVITE was accepted and a media session was established. All calls with 200 OK as the final response are typically billable (assuming they have non-zero duration), and a high percentage of 200 OK responses relative to total calls indicates healthy ASR performance.

What does SIP 503 Service Unavailable mean in my CDRs?

SIP 503 Service Unavailable in VOS3000 CDRs means the terminating gateway or server is currently unable to handle the call due to overload, maintenance, or capacity constraints. This is one of the most impactful error codes because it directly reduces ASR and often triggers gateway failover. If 503 responses are frequent from a specific gateway, that gateway may be under-provisioned or experiencing issues. You can use the Replace Failed Reason feature to change how VOS3000 handles 503 responses for failover decisions.

How do I reduce 408 Request Timeout errors?

SIP 408 Request Timeout errors indicate that VOS3000 sent an INVITE but did not receive a response within the configured timeout period. To reduce these errors, first verify that the destination gateway is online and reachable. Then check network connectivity and latency between VOS3000 and the gateway. You can also adjust the INVITE timeout settings in the softswitch parameters, but increasing timeouts too much will raise PDD for all calls. Also check whether the gateway is silently dropping packets due to firewall or NAT issues.

Why am I seeing 403 Forbidden in my H.323 gateway CDRs?

SIP 403 Forbidden appears when VOS3000 rejects the call because the source IP address is not authorized, the account is disabled, or a specific policy prevents the call. In the context of H.323-to-SIP translation, this code may appear when VOS3000 sends the call to a SIP gateway that does not recognize the originating credentials. Check the mapping gateway authentication settings, verify that the source IP is in the allowed list, and confirm that the account is active and not suspended.

What is the difference between 486 Busy and 600 Busy Everywhere?

SIP 486 Busy Here means a specific endpoint or gateway reported busy, but other locations might still accept the call — VOS3000 can continue failover to alternate gateways. SIP 600 Busy Everywhere is a global failure indicating that all known locations for the called number are busy, and VOS3000 should stop trying alternate routes. The key difference is failover behavior: 486 allows continued switching (unless busy stop switch is enabled), while 600 always terminates the call attempt.

Can I change how VOS3000 handles specific SIP response codes?

Yes, VOS3000 provides the Replace Failed Reason feature in mapping gateway settings that allows you to override how specific SIP response codes are handled. For example, you can change a 503 Service Unavailable to a 486 Busy Here to prevent aggressive failover that wastes CPS capacity. This feature is configured per mapping gateway and affects both routing behavior and the response code recorded in the CDR. See our termination reason replacement guide for details.

Get Expert VOS3000 CDR Analysis Support

Interpreting VOS3000 SIP response codes CDR data correctly is the key to identifying and resolving call quality issues quickly. Our VOS3000 specialists can help you build systematic CDR analysis workflows, set up automated alerting for problematic response code patterns, and optimize your routing configurations to maximize ASR.

Contact us on WhatsApp: +8801911119966

From CDR analysis to routing optimization and gateway troubleshooting, we provide comprehensive VOS3000 support. Reach out today at +8801911119966 and take control of your call quality metrics.

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