10G has been around for a long time, and finally we are starting to see implementations of 10G in data centers. However with bandwidth hogging applications on the rise, such as cloud computing, IP TV, Video on demand, etc, most telcos around the world are starting to upgrade their backbone to 40G and some have even begin testing 100G. Some of you might recall news on Verizon Business doing a successful trial of 100G optical service with JANET, a UK National Research and Education Network. IEEE has released a draft IEEE P802.3ba for both both 40G and 100G. Let's see what it contains.
IEEE P802.3ba draft has specified a single architecture for both 100G and 40G Ethernet. Other than increase in data rates to 100G and 40G, there will be no other change at the MAC layer, which means characterstics such as frame size and format, full duplex operation will be the same as in the previous architecture.
A PHY device connects MAC layer to the media. This device has a PMD, PMA and a PCS sublayer. PCS or physical coding sublayer is responsible for encoding and decoding of data bits into code groups and vice-versa from PMA. It also ensures clock transition density along with transportation of control signals and frame delineation. Also PCS uses the same coding scheme 64B/66B as used in 10G. PMA (Physical Medium Attachment) sublayer performs functions such as reception, trnamission, clock recovery and connects PCS with PMD sublayer. The draft also defines a common physical interface PPI (Parallel Physical Interface) for both 40G and 100G with the only difference being the number of lanes supported.
Each lane in PPI operates at 10 gigabit per second, so incase of 40G, there will be four transmit and four receive lanes, similarly for 100G there will be 10 transmit lanes and a smaller number of recieve lanes of 10 gigabits per second. The final version of the standard is expected by 2010. More details about the standard can be found at http://www. ieee802. org/3/ba.
The long talked about technology PLC or Power line communication has finally become a reality. As the name shows, PLC technology uses electric power lines for transmitting digital data. Since electric voltage and data signals waves operate at different frequences, there is no interference between them. This technology uses Wavelet-OFDM modulation and the maximum data trasmission claimed is upto 210Mbps. Currently this has been used largely to build smart homes. Just like most new network technologies, PLC initially did not have any standard and various PLC devices faced serious issues when communicating with each other. In Dec 2008, IEEE has released IEEE P1901 draft for Power line communications which defines medium access control and specifications of physical layer.
|DIGILINK's Plans for Next-Gen Networks|
1)What is the state of adoption of 10G by enterprises in India?
2) Standards for 40G and 100G are expected to be finalized by next
year. How do you see this space evolve ?
3) What is DIGILINK doing in this space?
According to IEEE, this is to create a new standard for high speed (>100 Mbps at the physical layer) communication devices via AC power lines, called Broadband over Power Line (BPL) devices. IEEE claims this standard will use transmission frequencies below 100 Mhz and will be usable by all classes of BPL devices, including BPL devices used for the first-mile/last-mile connection (<1500 m to the premises) to broadband services as well as BPL devices used in buildings for LAN and other data distribution networks(<100m between devices). More details about this can be found at www.hd-plc.org or http://grouper. ieee.org/groups/ 1901/
In FMC there are a few options available for enterprises such as PBX-centric, IMS-VCC, Unlicensed Mobile Access (UMA) etc. UMA allows carriers to provide mobile services over WiFi networks as defined by 3rd Generation Mobile Group (3GPP). With UMA users having UMA-enabled dual-mode cellular/Wi-Fi mobile handsets, they can roam as well as easily handover between wireless and cellular networks.
In a PBX-centric model, when a user's mobile comes within the range of
enterprise WiFi, VoIP or PBX-centric client software on the user mobile, it will
automatically connect to PBX, and the mobile acts as the client of enterprise
PBX and incoming calls shall automatically be directed to the user's
Another framework getting pouplar for Fixed-Mobile Convergence is IMS-VCC (IP-Multimedia Subsystem-Voice Call Continuty), which is defined under 3GPP release 7. It provides usage of a phone number or a SIP identity between cellular and WLAN.
The advantage of this system is that it can work with most cellular technologies such as GSM, CDMA and UMTS. It also supports seamless integration with VoIP networks.