Friday, January 13, 2012

DPI, Policy and Charging

I am particularly impressed by the amount subscriber management that 3GPP has provided. Per packet flow treatment per subscriber is super cool. However the implementation on mobile gateways is quite complex and need a lot of cpu and memory cycles. In simple words we really need powerful hardware sitting in edge with a efficient software to correctly enforce the policy and perform corresponding charging actions.  
Just to point out, 3GPP allows service provider to treat each subscriber differently based on the subscription. A subscriber may be allowed to use certain traffic or block certain traffic, certain traffic may be treated with higher priority and bill him based on the application or location etc. The limit is endless. A very good business model is needed to make it happen though. So to allow or block certain traffic from a subscriber the gateways need to look deep into the packets, detect the flows, apply policies and report to the billing system. This is quite a lot of pressure on the gateways.
I was doing a study of various telecom plans available across the world. Interestingly some service providers were offering services like free Facebook or free sport channel at a flat monthly rate or free email etc. This makes me wonder why we even need these plans with LTE. These plans are efficient when there is sever crunch of radio resources and subscriber doesn't  have fancy handsets, but with LTE the spectrum has widened and fancy handsets are becoming cheaper and cheaper. Will these plans still hold well?
For e.g a plan like free facebook will need the mobile gateway to look at all the packets  flowing from subscriber, zero rate it and then inform the same to the billing system. This churns a lot of bandwidth in term of cpu and memory cycles on the gateway. More over the software on the gateways needs to be highly efficient.
But there is other side to it. A subscriber may be offered limited data over a period of time but as token of appreciation allow a service free. For e.g I would be very happy if “Google Maps” is offered free along with my monthly of say 200 meg. I mean truly free here, that is actually look at the Google Maps traffic and zero rating it. But service provider may not want to do, so he may allow another 50 meg of additional quota and call it token of appreciation.  Duh!
In a nutshell, 3GPP subscriber management is amazing and I believe the broadband forum agrees. DPI, Policy and Charging are cool features on mobile gateways from engineering stand point. There are several other issues with DPI as people really don’t want service provider to look at their data. Anyway the service is available and I will leave it to the marketing to decide :-) 
I would like to hear from you. Would you like certain services to be free along with your subscription or would you like service to be free for a low monthly or weekly rate or any other plans you want to see in the market?


Cassio Sampaio said...

Hi Santosh, you bring up a fascinating discussion which I have been quite involved for the last five years. I have observed a huge trend towards offering data plans that offer subscriber the killer application in mobile - price certainty.

Subscribers want the peace of mind created by service offerings that enable them to consume data without the need to translate bytes into Dollars/Euros/Pounds. The other very powerful angle as you touched briefly is data sponsorship access better illustrated by some of the e-book readers and some digital cameras where the bandwidth required to consume the services provided by the device is funded by a third party.

The technology required to enable those types of services exist today and as you highlighted there are challenges around the implementation of such directly in the packet gateway but also other challenges related to the fact that many service providers offer more than one type of access type (3G, LTE, CDMA, WiMax, etc) and harmonizing the services across all different gateways would be a rather daunting if not impossible task. In even a more simple note, implementing the same plan in two different access gateways (several carriers have a dual-source vendor strategy), particularly if they depend on correct application identification can be rather difficult if not impossible.

I touched upon some of these points in a recent webinar archived here:

I hope you will find some if useful.

Rakesh said...

It will be really cool to have those services free of charge if customer agrees in the contract of certain type.

eg. i ended up paying $15 more this month only because i used google maps alot while travelling and push services were by default enabled on FB so new year wishes overflown using the 3G crossing the monthly limit.

I guess this was happened with many of us recently. customer will definitely ask for certain data plans that will some of the unlimited services.

The integrity of the data can still be kept even using the DPI.


Santosh said...

Thanks Cassio & Rakesh for the comments!

Eric A. Smekens said...

Hello, Santosh,

Your analysis is very good, and I share it.

At the end, what's the value of the money.

Nevertheless, MNOs have a huge growing concern: getting stuck on their air interface, due to limited bits per hertz, and still limited hertz-bands, even with the new 4G ones. So, there is the problem.

It appears that 40% of the users use 70% of air interface bandwidth, impacting quality of experience of the other users.

PCC is a tentative answer to this problem, although controlling the up-link traffic still remains a problem, as PCC primarily controls the down-link traffic?. Also, central control on traffic will not avoid to have a congestion on local BTS. This is why I see PCC vendors putting now PCC-like control elements behind BTS. It only makes the complexity even worse.

Kind regards,

Eric A. Smekens

Santosh said...

Hi Eric

I agree with you. Uplink is stil a problem. While you cannot control what UE is sending in uplink, I believe there is some effort going on in 3GPP/operator community to control congestion on eNBs.

Thanks, Santosh

madhuri said...

IN physical layer (UMTS), why am using 10,20,40 and 80 ms radioframe.PLZ send me a reply.