August 28, 1998

Voice over IP VOIP: Dream or a Reality

Date 28th August 1998
Voice over IP (VOIP) has been talked about more than SMTP and POP. The proposition which makes this talk so redundant is the fact that many a comparative studies have shown the call charges to fall to over 1/50th of the cost as of today. But there is more to it. This article would cover various issues including the technical, legal and ethical issues behind implementation of this highly talked about technology on Internet and particularly in India.

Technology

Voice over data network is not something new, as Voice over Frame Relay has been very successful for sometime now. However what keeps IP a step ahead, is its ability to address the issues of a global protocol and global accessibility over public data network. Moreover for Intranets also IP has certainly proved to be a better protocol than all the others for WAN networks worldwide.

Unlike the Plain Old Telephone System (POTS), which is a switched network, routing voice over IP has the ability to address some network redundancy and efficiency issues which POTS can’t. IP is built over self learning routing protocols which can actively route traffic over multiple routes to the same destinations in the event of network failure on a particular route. But the more important issue, which IP solves, is the data compression, which occurs at the source router. This allows almost 8 to 15 times more voice channels on the same bandwidth for the same quality. More over the kind of error correction involved in the routers or VOIP equipments at the end point can easily take upto 25% packet loss without much degradation in service.

However the impression that you need to have a multimedia system on every computer to use this technology is wrong. There have been successfully implementations of VOIP, particularly in Singapore and Australia between exchanges, which allows one to continue using POTS equipment at the end points. You may also, alternatively, use your computer’s multimedia to connect to POTS equipment at the other end.

Still VOIP has some issues, which makes it a bit more than far-fetched dream for now. The most important issue that needs to be addressed is the issue of QoS (Quality of Service) possible on the IP infrastructure. IP has a major drawback in its ability to facilitate prioritized traffic. Voice which is a real time traffic needs to get across from one terminal to other within a specific duration of time, after which the data is of no use. This requires the routers in between to recognize this traffic as high priority traffic and allow them through without making them stand in queue. Also if this traffic can’t be let through within a specific time, the routers could be advised to drop the packets altogether as its of no use any way. Though there is a built-in facility of indicating priority within IPv4 using the type of service and precedence bits in the IPv4 packet. However this requires that the initiating application to insert these bits which give about no reason why a certain traffic should not be given high precedence. Which in other words makes the facility redundant. Because of this reason most of the routing technology and applications ignore these bits.

The other way of attacking this problem was by designing a mechanism in which only the Service providers would be provided with the ability to prioritize the packets. RSVP (Resource Reservation protocol) is one such effort by the IETF (Internet Engineering Task Force) to address this issue. The protocol allows high priority channels (similar to virtual circuits in packet switched network) to be created between multiple routers to allow high priority traffic flow. RSVP which is now supposed to be supported by many a routers still faces lots of performance issues which is why companies like CISCO and IBM are going ahead with their own variation of the QoS or Differential services which can do that same job.

It is because of this very important reason along with a few more that most of the VOIP vendors are concentrating more on corporate networks rather than Internet. A Company like Micom, which is heavily VOIP related technology, admits whole heatedly that IP is fine for Voice, but Internet is Not. In other words Internet may not be the only medium to carry IP traffic. Many corporate which have their own high speed Intranets feel its more economical to switch to high efficiency private Intranet IP leased lines than using long distance calls using their local telco. Moreover with the provision to attach many PBXs with routers, its more of a reality which already exists in many companies around the world. Micom it self has sold over ten thousand pieces of VOIP equipments till now.

A reasonable argument suggests that taking everything into considerations the IP industry good wishers would soon be seeing voice traffic over IP in about 1/10 of the normal cost for the same performance.

VSNL and VOIP

For most of the people in India Voice over IP is nothing more than voice transmission going over Internet using their home Multimedia system. There are different companies providing the same service and web-site of most of them have been blocked, thanks to the VSNL ideology. During a interesting debate over this technology at Internet World with Mr.Amitabh Kumar, he admitted that VSNL has been blocking these sites as the products they provide are illegal to use in India. Further it has been informed that closing on a particular port use on the VSNL network has technologically blocked the products they provide. Work around for that exists but that is another story. Among the more interesting details talked about during the debate was the interesting issue whether VSNL has the power/authority of blocking even Web or Email traffic to these sites which is one of the most important resource points for budding engineers in the IP sector. And still more interesting is the fact that though VSNL has been blocking these site for the age old 18th century telecom regulation it has not even taken an iota of step towards blocking even more problematic pornographic sites like playboy, which is also illegal to view under Indian Law. According to its blocking of these sites which would show VSNL in a better light than blocking of Technologically advance sites like Vocaltec which are in fact VSNL’s competitors in a way. If money is the only thing VSNL sees then it may be right, but if VSNL is talking about legal issues then it better complete its job it started or its intentions would be doubted.

However VSNL admits that there is no limitation on off line voice over IP which means that you are not doing any illegal transmission when you send mail with voice attachments.

Moreover VSNL’s current announcement of it having more than 70Mbps is a welcome note, but is far unrealistic if one is thinking of running VOIP applications on it. Hopefully soon we would be seeing multiple Internet backbones (including the DOT national Internet backbone) all connected to each other around the country creating a thick backbone sufficient enough for a more realistic infrastructure for voice calls.

IT Task force has been voicing its concern over this age old law to be struck down with a more flexible self correcting law to enable this highly dynamic industry to make use of everything its got. Allowing VOIP is just another form of liberalization that will happen. If not today, it would tomorrow.

There are some people who are thinking of public interest law suite, to stop VSNL from blocking all IP traffic to VOIP providers, as VSNL does not have power to block or limit use of WEB or Email access to them. I hope issues like these don’t reach that extent, as VSNL has been very cooperative in the past and hopefully would be in the future. All I can say right now is that my IP enabled phone may be a few years late to reach my table top, till then POTS zindabad.