DIY -VoIP – Do IT Your Self
“Reduce bandwidth usage of VOIP route up to 80% .. Start saving money !”
“This SIP calling software has majorly two benefits- first, it helps in bypassing internet firewall and second, it reduces bandwidth consumption by up to 70%…!”
These are the slogans of some VoIP product seller websites.
Do you believe if someone says that there is some technology which reduces 80 % of bandwidth usage on a voipcall which is already encoded with low badnwitdh codecs?. Then why should one wants to pay royaltee fee and use the low bandwidth consumption codecs like g729 and AMR ?.
Low bandwidth codecs are meant for voice packet compression. You can consider that a voice packet is already compressed if you are using a low bandwidth consumption codec .
I am pity on some people who are paying so much money on some useless VoIP solutions.Some VOIP software developers are selling nonsense to the customers by keeping the fact in mind that most of the VoIP customers are non-Tech-savvy .
SIP and RTP headers can be compressed and some of the attributes can be omitted to reduce the packet size .
Imagine if some one is explaining you about a third person like this
“His name is peter , his height is 5.10 , he is wheatish in color “
If the same would be explained like this
“He is peter from india , he is 5.10″ and 60 KG, wheatish complexion. He is married and has 2 kids . He has compeletd his masters degree from university of Delhi. He is an introvert and has great taste in movies . His hobbies are watching movies , playing football “
Obviously the second introduction is more detailed and memorable .
Sip ,RTP protocols are defined in internet standard documnets ( RFC 3261,3550 etc., by IETF ). You can omit some of the attributes in header while developing a sip stack .
You can use silence suppression= on if your equipment/software supports that.
Using low bandwidth codecs will reduce bandwidth coset and improve voice quality.
If you want to by pass VOIP packets through firewall or blocked networks you can use VPN solution like OpenVpn .
Still VPN might be blocked in some coutries… it is not our subject and I can not discuss how to hide VOIP packets from ISP s in those countries.
Recently , we have implemented a openvpn based site to site solution for a customer as he has dynamic internet IP address at one end and also firewalled environment .
This solved 2 problems of his ,One is dynamic public ip problem and the other is bypassing VOIP packets through firewall .
We just need to take care of some VPN optimisation things then it will work without a hitch.