Wednesday, September 22, 2010

Difference Between VC Based Multiplexing And Logical Link Control Encapsulation in ATM?

I have been stumbling since last week to understand the concept behind AAL5Snap and AAL5Mux encapsulation. Finally I made my self clear by reading RFC 1483 which explicitly depicts about the difference and usage of both Atm Adaptation Layer 5 encapsulations. These encapsulations techniques are used when user willing to carry the multiple protocol traffic over PVC. It is defined in two ways:-
1. VC based Multiplexing (AAL5Mux)
2. Logical Link Control Encapsulation (AAL5Snap)

VC based Multiplexing (AAL5Mux) is used to carry one protocol per PVC. e.g. If we want to forward IP and IPX over ATM, in this case we need to define two dedicated PVC. One PVC will carry IP and another will carry IPX. As the number of protocols will increase, PVC will also increase.

Logical Link Control Encapsulation (AAL5Snap) is used to carry multiple protocols in single PVC. In this case user multiplex all the protocols in one PVC. To differentiate PDU, Logical Link Control header is added.
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Thursday, September 2, 2010

3G Services Licence Issued

The Government on Wednesday allocated spectrum for third generation (3G) mobile services to operators including Vodafone Essar, Reliance Communication and Tata Teleservices.
Mr Syed Safawi, CEO - Wireless Business, RCom “By releasing the 3G spectrum as promised, the Government has paved the way for the next revolution in mobile telecommunications. Reliance Communication is fully geared to bring alive this superior 3G experience to all its consumers.”
Tata Teleservices Ltd spokesperson said “We are delighted to have received 3G spectrum for commercial use in nine telecom crcles after the amendment in the UAS Licence. As announced earlier, we have already placed orders for 3G network equipment. We will now closely work with our partners NTT DoCoMo, acknowledged as the world leaderin telecom technology development, to put our network and content in place. We look forward to speedy rollout of world-class 3G services which will redefine the telecom experience in India.”
Licence disputes
“We are pleased to receive the spectrum today. Our implementation is on schedule and we will launch 3G services for our customers in a few months, “said Mr Samaresh Parida, Director Strategy, Vodafone Essar.
However, Aircel and Idea Cellular's plans to roll out third generation (3G) mobile services in Chennai and Punjab respectively could get delayed with the Department of Telecom caught in a technical issue with respect to licensing. While in the case of Aircel having two separate cellular licences for Tamil Nadu and Chennai is coming in the way, for Idea Cellular having overlapping licences in Punjab is the problem spot.
Under the old cellular services regime, Chennai and Tamil Nadu were divided into the two separate circles. As a result, Aircel had got two separate mobile licences. However, when it came to 3G auction, the DoT considered Tamil Nadu and Chennai as a single unit. Post-the auction, the DoT is issuing amendment to those bidders who already have a licence incorporating the new 3G guidelines.
In Aircel's case, the Tamil Nadu cellular licence does not include Chennai; therefore, the DoT cannot amend service conditions for Chennai to include 3G services.
Idea Cellular may have to surrender one of their licences in Punjab. Idea had got its own licence for Punjab, but also acquired Spice Cellular which had operations in the same circle. The company has been seeking a refund for surrendering the licence.
Source Hindustan Business Line

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