4351 CUBE SRST consultative transfer no audio

[Kenneth Mohammed]

Hello Gang,

Its been a good minute since I have posted here.

I have a 4351 CUBE that is currently in SRST (ESRST). All is working fine, with the exception of consultative (warm) transfers.

When we call in from the PSTN, the receptionist answers, and attempts a warm transfer. After consulting with the transferee, she hits the transfer button. The transferee's phone rings, and he answers, but the PSTN caller hears no ringback, and upon answer, hears no audio. However, the transferee can hear the PSTN caller. Blind transfers work fine.

We also notice this happens with ad-hoc conferences. The receptionist will conference a PSTN caller and an internal caller, but once the receptionist drops, the conference stays up (as it should), but still the PSTN caller cannot hear the internal user.

This isnt a routing issue, as the CUBE and the phones are all on the same subnet.

IOS is 16.06.05. Bug maybe?

[Roger Kallberg]

I don’t know if it is a bug or not, but 16.06.05 is a very old release train of IOS. I would recommend to update to something more current, like 17.6.4 as that is a stable and well proven release.

[Nithin Eluvathingal]

As @Roger Kallberg  mentioned, you must upgrade the version to 17.6.4 and recreate the issue. 

[Jonathan Schulenberg]

The OP needs to sort out CUBE Smart Licensing before they upgrade beyond IOS-XE 16.9 to avoid an outage 90 days after the upgrade. CiscoOne with SWSS, L-CUBE with SWSS, or a current A-FLEX-3 annuity offer are viable paths forward; FL-CUBEE-xx will require a new order for A-FLEX-3.

CUBE and SIP SRST co-residency was added in IOS-XE 16.7.1. The OP should consider upgrading to the last 16.9 build to see if it helps. Also review the config guides for this; I believe SIP multi-tenancy is required to make this work.

CUBE Configuration Guide Supported Platforms chapter

SRST System Administrator Guide Configuring SIP Trunking on Unified SRST chapter.

[Kenneth Mohammed]

I forgot to post the fix:

voice class sip-profiles 99
request REINVITE sdp-header Audio-Attribute modify "inactive" "sendrecv"
request REINVITE sdp-header Audio-Attribute modify "sendonly" "sendrecv"
request INVITE sdp-header Audio-Attribute modify "sendonly" "sendrecv"
request ACK sdp-header Audio-Attribute modify "sendonly" "sendrecv"
response 200 sdp-header Audio-Attribute modify "sendonly" "sendrecv"
request REINVITE sdp-header Audio-Attribute modify "inactive" "sendrecv"
request REINVITE sdp-header Audio-Attribute modify "sendonly" "sendrecv"
request ACK sdp-header Audio-Attribute modify "sendonly" "sendrecv"
response 200 sdp-header Audio-Attribute modify "sendonly" "sendrecv"

voice service voip

sip

sip profiles 99 inbound