How to configure Grandstream VoIP GRP2601P with BSNL FTTH

[amohan78]

I have successfully bridged the VoIP VLAN to my router and one of the LAN ports is now giving the VoIP IP Address. BSNL VoIP is based on DHCP unlike Airtel which is based on Statis IP.

Now I want to connect a IP Phone like Grandstream 2601 to that LAN port and more away from my analog FXS based system. In BSNL Telephony configuration, the Outbound Proxy URL and Port are mandatory, and Outbound Proxy needs to be enabled. I was about to purchase this model.

before that I thought of looking at some configuration videos and I saw that the SIP registration page does not have explicit fields to mention the port of the outbound proxy. BSNL has a Proxy Address URL like wb.ftth.bsnl.in and a port like 5080 along with it. Nowhere I find that the port number field is present.

Has anyone connected a IP Phone with BSNL FTTH and can anyone let me know how you have dealt with the Grandstream VoIP phone configuration ?

 

[amohan78]

Everyone, I ultimately could configure Grandstream GRP2601P as BSNL VoIP phone. Butthe journey has been quite a difficult one.

See the experience point by point.

1. There is no adaptor except for the base model of GRP2601. Since all are PoE devices from base+1, I had to buy a PoE injector.
2. The SIP and Outbound Proxy port need to be defined at the start. The SIP port assumes port number 5060. But the Outbound Proxy port did not assume it ! I had to give FQDN:5060 as per the document shared by @hariselio in this thread. So to reiterate, the SIP Address must not have the port number. The Proxy port must have the port number.

Till this point, it was easy. I could dial from the VoIP to my mobile and back from mobile to VoIP. I could also dial my friend's PSTN number as well. Then came the real challenge. I could NOT dial any BSNL Landline number that was given via BSNL FTTH. So at my father's place, I have converted from the PSTN to Bharat Fiber and the landline was converted from Copper line to Bharat Fiber based Landline. The moment I dialled that number, I got a message that the subscriber is not picking up any calls at the moment. I enquired at my father's place and there was no incoming call that has come to his place yet.

Now this was a harrowing experience. What I came to know,

• BSNL uses different IMS cores across regions (e.g., wb.ftth.bsnl.in, upe.voip.ims.bsnl.in).
• Mine was ktd.ftth.bsnl.in
• If your call is routed between two different IMS cores, and one doesn’t properly forward SIP INVITE or ACK packets, the call may fail to mature (ring or connect)

• Grandstream phones typically default to G.711 (PCMU/PCMA), but BSNL’s IMS might expect G.729 or other codecs
• Also If SIP ALG is enabled on your router, it may be modifying SIP headers in a way that breaks the call setup

So, I did the following things,
Enabled all Codecs
made the NAT Traversal as Keep Alive
Disabled all SIP ALG from my TP-Link ER605 as well as VSOL ONU

NO LUCK.

Then I realised that my father and myself are in the same IMS core. So I tried with Zoiper and it worked jolly well.

it only means that, if Zoiper connects and completes the call, but the Grandstream 2601P fails—especially for intra-core landline calls—then we’re dealing with a device-specific SIP signaling issue, likely tied to how Grandstream handles headers, NAT traversal, or codec negotiation.

1. Disabled codec iLBC
2. This one was weird. Mark the parameter "P-Asserted Identity Header" = YES

This one made the trick. The intra-IMS core calls matured and it has started to work now. !

 

[amohan78]

Marking the thread as complete NOW.

SOLVED

 

[hariselio]

I thought you were using Mikrotik hex s? That should have poe out in port 5 and i guess you can power hex s using poe injector's power supply which is supposed to be around 48v. And connect eth5 to voip phone. In this way you can reduce one power supply

 

[amohan78]

@hariselio
Already gave an attempt. The Eth 5 is a passive PoE out port. VoIP Phone requires a PoE input that is compatible to IEEE 802.af PoE. Passive PoE out port of Microtik's Eth 5 is not compatible to IEEE 802.af. I had already tried it, It was showing a red colour on the LED telling that it is not compatible. I turned on Forced ON as well. It did not work.

 

[hariselio]

@amohan78 Did you use the power adapter given with your poe injector or the default one came with hex s? Hex-s power adapter is 24v rated and it won't work for voip phone, but if you power the hexs using the adapter which came with your poe injector, it should work ideally.