PGW2200: No ringback tone on ISDN <-> SS7 interworking

[mikima777]

When call is coming from PSTN side through SS7(ISUPv2) and is terminating on ISDN pri-net5(ETS_300_102), which is backhauled to PGW2200(in call control mode), caller(originating side) doesn't hear ringback tone if PBX, attached to ISDN doesn't provide it in-band (i.e. sends sends Alerting with PI=8)

According to paragraph 2.1.4.7 ITU-T recommendation Q.764 destination exchange (i.e. PGW2200) should apply ringback tone to the transmission path to the calling party.

I will appreciate for any comments.

[mikima777]

2.1.4.7 Through-connection and awaiting answer indication at the destination exchange

The sending of the awaiting answer indication (e.g. ring tone) at the destination exchange depends on the type of call. On speech, 64 kbit/s unrestricted preferred, 3.1 kHz calls and calls to an analogue called party the awaiting answer indication is applied to the transmission path to the calling party from the destination exchange on receipt of an alerting indication from the called party or from information contained within the destination exchange that the called party will not or is prohibited from providing in-band tone.

Regardless of whether tones are to be provided or not, the destination exchange will through-connect after the reception of the connection indication from the called party and before sending the answer/connect message to the preceding exchange.

If the destination exchange does not send the awaiting answer indication because the destination user provides for the sending of tones, then the destination exchange will through-connect the transmission path in the backward direction on receipt of the progress indication.

The complete through-connection of the transmission path at answer is covered in 2.1.7.

[mikima777]

I discovered one more problem: When the call are coming from VoIP network through HSI(ver 4.1), MGC(ver 9.4.1) sends to media gateway ringback request, but instead of sending S:G/rt it sends S:rt, i.e. mgc doesn't explicitly points that rt signal is containintg in Generic package. So in order to get a Ringback tone on the line gm-package should be chosen as default mgcp package instead of trunk package on the media gateway

[KONSTANTIN FEDOROV]

This is correctly.

From the MGCP RFC.

If CA send command and doesn't explicitly point

Package name.

Endpoint must understand this via configuring

default package.

"The package name is OPTIONAL for events in the default package for an

endpoint, however it is RECOMMENDED to always include the package

name."

[mikima777]

May be it's not a bug, but it looks like a bug. If, for example, i will need to perform COT testing and MGC will send the signal without package name to MGW? In this case i will have to choose trunk-package as default package and ringback tone on some calls will be lost

[mikima777]

One more problem with PGW2200 and PRI backhauling: if customer configures an ISDN trunk for overlap receiving and sends a setup message with no called party number in order to obtain a dial tone,, PGW2200 doesn't provide it

It seems that either i am completely stupid or PGW2200 is a full of bugs.

[mikima777]

It seems that noboby are using PGW2200 with PRIs

And what about Cisco voice expert engineers/developers? imho they should be aware about how to configure their product :(

[KONSTANTIN FEDOROV]

Hello,

Unfortunately, PGW couldn't generate any tone, because

it doesn't have resources for this.

Could you send me configurations of voice GW, which connected to the PBX which didn't apply ringback tone.

e-mail in my profile.

[mikima777]

PGW already generates(actually not generates, rather sends signals to MGW to generate ringback) ringback tone on VoIP(HSI) -> PSTN(SS7) calls

I will send MGW configuration on your e-mail.

Thanks for response !

Mikheil