Why telecom equipment vendors should worry about wireless backhaul ?

There are a lot of application to count as far as the bandwidth hungry applications are concerned. I am considering the wireless backhaul here and to my understanding following are the key drivers in fueling up the bandwidth demand from backhaul. I am covering the following here;

• IP Multimedia Subsystem (IMS)

• High Speed Downlink Packet Access (HSDPA)

• Mobile TV

• Mobile Virtual Networks

• Mobile Telepathy

• 4G Networks

These technologies will drive the future telecom business to newer speeds and bandwidths. Do post a comment if you have one.

IP Multimedia Subsystem (IMS)

IMS was primarily defined by 3GPP and is intended to make Internet services available to everyone from anywhere, new or old, with best possible performance. It can be viewed as a generic architecture for both multimedia and voice over IP services. It can support multiple access types such as GSM, WCDMA, CDMA2000, WLAN, fixed broadband and other packet data applications.

Some of the possible applications where IMS can be used are; Instant messaging, Multimedia advertising, Multiparty gaming, Videostreaming, Presence services, Web/Audio/Video Conferencing, Full Duplex Video Telephony and Push-to services, such as push-to-talk, push-to-view, push-to-video.

IMS is a set of IP-based services which can be carried over both packet- and circuit-switched networks, irrespective of the mode of transport, in both wireless and fixed access technologies.

High Speed Downlink Packet Access (HSDPA)

HSDPA was developed for W-CDMA. It is a packet based technology with data transmission rates of upto 15 times faster than GPRS and 5 times faster than UMTS while recently it is tipped to deliver upto 14.4 Mbps.

Both institutional and individual users will directly benefit from the increased throughput with connections speeds comparable to the fixed-line broadband access, especially where xDSL connections are still popular. Corporate users can easily migrate to HSPDA for the mobile uses and it will be a great relief from time consuming mail downloads and other corporate information. In addition, consumers can enjoy superior quality for video services, including video streaming, gaming and fast Web browsing.

Mobile TV

Mobile TV is one of the forthcoming trends in the market. It is yet to hit in a big way but sooner or later it will make its way to the mobile devices. With the advent of high data rates available in air 3G and upcoming 4G networks will be able to stream mobile TV. It is to be seen how multicasting of various channels is done to the subscribers.

There are three main contenders in the game of mobile TV broadcast; DVB-H (Digital Video Broadcasting) in Europe, DMB (Digital Multimedia Broadcasting) in South Korea/Japan, and MediaFLO in America. Watching TV using any of these technologies requires a TV -capable handset. Among the three technologies, DVB-H is officially adopted by ETSI and is being watched closely.

Mobile Virtual Networks

Just like Virtual LAN concept in the fixed network counterparts, a concept of mobile virtual network is coming in the wireless arena. It can be viewed as ELAN concept from MEF services, where an operator or company which does not own a licensed spectrum, nor the networking infrastructure but instead resells wireless services under their brand name, using regular telecom operator's network with which they have a business arrangements.

There are Mobile Virtual Network Operator in Europe, America and Australia. They are expanding in Asia and one very well known name in the field of MVNOs is Virgin Mobile. They are expanding at a very high rate. As of now MVNOs are not regulated and yet to reach their full potential. Just like the concept of access network owners and providers is separating, wireless domain is also seeing it in its coming in near future.

Mobile Telepathy

This may be covered as an application offered through MVNs. It is largely useful for the remote and difficult to reach areas. Similar applications have found the place in the rural Tamilnadu, India (to my knowledge) and is found to be very feasible to the end users who are well below poverty line. However, medical help and check up with suitably equipped mobile hospital, it can bring revolution to the medical facilities, especially difficult to reach areas.

4G Networks

4G is the successor for the 3G networks and lot of research is going in this field. It is expected to go under deployment towards 2010 - 2015.

The 3G advances are being driven by video and TV services while the QoS at low cost yet at higher speed, would drive 4G along with the advent of newer services. Another driver of 4G would be convergence of the service and not only the networks. With MVN Operators coming into play, the service domain may completely be different then the access domain or better known as the physical infrastructure domain. With 4G and MVN together would compete with their fixed network counterpart in terms of service models as the high data rates will be available, for data and streaming applications.

It is evident with the growth in last one decade that the mobile terminal usage (laptops, PDAs, high-end phones) is expected to grow exponentially.

Conclusion

One can count of many, as in Software Radio, the mobile advertising etc. but they somehow are inter-related and can be largely covered in the generalized set of above mentioned set of technologies. But one never knows, future may bring lot more applications.

Protection switching in PBB

Well for the PBT network, path redundancy is definitely important. As this is evolving, some of the vendors are suggesting a MPLS like label-switched-path setup where an alternate path is made for every traffic carrying path in either 1:1 or 1+1 (G.8031) fashion. As my previous blog goes, it applies to the management plane implementation of a fully managed PBT networks.

Other way of achieving this, is a control protocol. The challenges for a de-centralized control plane is that it has to understand many specific scenarios which can come up in the deployed PBT network. Being the core, the 50ms resiliency is very important. Existing solution of xSTP is way too slow to respond to this particular scenario. Give that the network may be fully or partially meshed, it would become rather complex to converge everytime and having multiple redundant paths, would only lead to a complex topologies even with low density networks. It goes against the conventional STP and STP like protocols. In addition, as soon as a new node is added into the network, reconvergence of the network topology is started because of new paths are now available for the traffic to move, which may be undesirable for the carriers in their core. Yet another issue could be the fault detection and propagation towards the root node or the responsible node which is chosen to take the corrective actions after the fault is discovered. Latency issues and the complexity of the control plane are the drawbacks for this approach.

It is therefore evident that a control plane driven PBT may end up being more messy and complex then a management plane driven PBT network.

However, a management plane driven PBT network has its own problems to solve. Every time a new node is added, it has to be configured through the same management tool which is used for rest of the network. So, a human intervention is more. A failure of the management tool might have its own issue and it always has to be backed with a redundant management plane software, having its own complexity issues.

So for the time being, it seems, G.8031 is the way to go along with Y.1731 for fault detection, unless there is a better alternative proposed in the area of protection and/or loop avoidance for the PBT network within its QoS parameters.

What is it, a fully managed PBB-TE or with a control plane ?

Debate is going on over the Traffic Engineered PBB to have a management plane which is pre-configured and to have a resiliency time well below 50ms. Another option which is being thought of is having a control plane much like the GMPLS, with a drawback of having resiliency time constraints. The GMPLS control plane is also evolving to give space to PBT under a common efforts to have greater flexibility in the control plane with draft-fedyk-gmpls-ethernet-pbb-te-01.txt and later versions. This calls for a strong OAM&P support. MSTP is expected to be used within the PBB Edge devices with less number of nodes so as to reduce the convergence time, still the handshake is slower than 50ms. It is claimed that PBB-TE with control plane would ensure that the time constraints are met, however this is still a question.