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Polycom BLF issues: SIP 482 loop detected

Occasional Contributor

Polycom BLF issues: SIP 482 loop detected

Hi all,

we are experiencing a strange issue with BLF with polycom Phone on our IP PBX system.

BLF on polycom phones does not work and the phone return SIP 482 loop detected error on received notify message.


Our system structure:

Opensips balancer ( in the trace)

Freeswitch media server ( in the trace)

the phone has ip address, ext 8752 is trying to monitoring 8666.


Subscribtion seems to be accepted by the freeswitch and the notify is sent to the phone.

This one anyway replys with a SIP 482 errors. Any ideas?

Please find attached a trace and our phone config.


Phone firmware version is UCS 4.0.7. We also tried to downgrade to 4.0.5, 4.0.6 and 4.0.4 without any changes.


Please help.





Message 1 of 4
Occasional Contributor

Re: Polycom BLF issues: SIP 482 loop detected

Hi all,

just to update you about the state of the issue.

The problem was on the Cseq index (inside the notify dialog). It seems that freeswitch reach the maximum value (2^32 unsigned) but for Polycom endpoint the maximum is 2^31: this is why the phone detects the loop and reply as 482.


We are testing a patch on freeswitch (moved from 1.2.23 to 1.2.24).

Let you know about results. Till now everything seems to be fine.






Message 2 of 4
Occasional Visitor

Re: Polycom BLF issues: SIP 482 loop detected

Was this problem ever fixed?


We are getting floods of "482 loop detected" messages in call flows which, upon analysis of the PCAP and the PBX configs, do not show any evidence of actual looping. However, the report of looping from the phones is causing call failures.


We are using Polycom VVX 300s and 400s running 5.5.2 firmware.


Please advise.





Message 3 of 4
Polycom Employee & Community Manager

Re: Polycom BLF issues: SIP 482 loop detected

Hello Dave

The original poster updated the topic with their solution already. This was back in 2014

If you are seeing a similar issue please get this into support

Replied via a mobile device
The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. My official "day" Job is 3rd Level support at Poly but I am unable to provide official support via the community.


Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
Message 4 of 4