Friday 6 November 2009
Inter-Layer Communication Primitives
Sunday 14 June 2009
Verizon's bold step towards IPv6
As CircleID blogger and Pennsylvania State University senior systems programmer Derek Morr notes, the adoption of IPv6 is going to be particularly important for wireless carriers that are expecting a surge in mobile data traffic in the next few years, as they will need a fresh batch of Internet addresses to handle the multitude of wireless devices that will hook onto their networks.
Verizon is planning to launch its LTE services commercially in 25 to 30 U.S. markets in 2010. The network will be the first mobile broadband network in the United States to be based on the LTE standard, which is the latest variation of Global Systems for Mobile Communications (GSM) technology that is used for 3G High-Speed Packet Access (HSPA) networks. AT&T and T-Mobile have also announced plans to commercially launch LTE networks after 2010, while Sprint has already commercially launched its high-speed mobile WiMAX network.
One of the biggest drivers for carriers upgrading their mobile data networks to 4G technologies is the expected explosion in demand for mobile video services. A recent Cisco study on Internet traffic trends projects that 64% of mobile data traffic will be for video by 2013, vs. 19% for data services, 10% for peer-to-peer and 7% for audio. The study also says that the projected video traffic will increase four-fold between now and 2012
Wednesday 25 March 2009
Difference between SDU and PDU
Going back to the basics, a protocol stack consists of many different individual protocols. Protocols can be simply described as set of rules that allow communication between peer entities or they can also be described as set of rules that facilitate horizontal communication. Now these protocols are arranged in layers as can be seen in the figure above. In the transmitter side, a layer N receives data from layer N+1 and this data is called the SDU or Service Data Unit. This layer will modify the data and convert it into a PDU or a Protocol Data Unit. The peer entity in the receiver is only able to understand this PDU.
In simplest form, this modification by layer N of the layer N+1 SDU contains encapsulation. In encapsulation, the SDU is preserved as it is and an additional header is added by the layer N protocol. The modification can also perform concatenation (where more than one SDU is combined in a single PDU), segmentation (where a SDU can be split so that different parts of it end up in different PDU) and padding (where SDU is so small that filler bits are added in the end to complete the PDU).
In the receiver side, the peer entity receives the PDU from layer N-1 (its actually layer N-1 SDU) and convert it back into SDU(s) and passes it to layer N+1.
Second Figure Source: 3G Evolution - HSPA and LTE for Mobile Broadband, Erik Dahlman et al.
Saturday 22 March 2008
Healthcare using BWA (Broadband Wireless Access)
Thursday 6 March 2008
IPv6! One small step for man, one giant leap for mankind
3G Americas has published a whitepaper urging wireless service providers to start making a transition plan asap.
Anyone who has studied TCP/IP in their studies would know the basic problem with IPv4 is that the address is only 32 bits long and this allows a theoretical maximum of 2^32 addresses. Ofcourse practically the number would be far less because some of the address are either reserved or wasted due to the way the networks are designed (Subnets, etc).
To transition to IPv6 or not? A critical question for many service providers is when to transition to IPv6. As pointed out earlier, IPv6 has several benefits which will result in a simpler, more powerful and more efficient network. The sooner a service provider achieves these benefits, the sooner it will be at a competitive advantage compared to service providers who delay transition. The risks of delaying the transition are the following:
Managing a dwindling IPv4 address space will become increasingly expensive. Address
allocation requires careful planning; previously assigned address blocks may need to be
recovered, which is a complex process; and the management of additional devices such as
Network Address Translation (NAT) devices add to the cost.
services as service providers that have made the transition to IPv6. The ability to support
always-on and peer-to-peer services is impaired when traffic has to traverse NAT devices.
For example, always-on services require that a user is always reachable and therefore
cannot share a pool of public addresses with other devices. This can be mitigated through
address and port translation, but also that has its limitations.
unattractive as a roaming partner to service providers who have made the transition. The
same may be true in retail/wholesale relationships.
In the end, we believe that service providers don’t have the option to delay IPv6 introduction. The exhaustion of IPv4 addresses will force a transition to IPv6, and as pointed out earlier, address exhaustion may become a reality within the next five years. From that point on, service providers will face an increase in operations cost, if not because of introduction of IPv6, then due to the complexity of running an IPv4-only network with a diminishing pool of addresses.
With careful planning, the risk of early adoption can be mitigated significantly.
Tuesday 13 November 2007
Carrier Ethernet Transport (CET)
Another technology being discussed nowadays is Carrier Ethernet Transport (CET). Though this is not a wireless technology as such, it would still be very important as (can be seen from the diagram) the user data will be carried over this to the core.
A simple and straightforward explanation was not as easy to find but here are some more details which will give you a good idea.
Good source of introduction is this article from Meriton Networks:
A good introduction is an article in Lightwave titled, "Carrier Ethernet transport: No longer 'if,' but 'how'". There are some very good diagrams explaining the concept and its difficult to reproduce them here.Carriers around the world are increasingly being pressured to provide new services while reducing their costs to remain competitive with changing regulations and new, non-traditional entrants into the marketplace. As carriers migrate to next-generation networks (NGNs) to reduce their costs and improve their ability to support high bandwidth-intensive services with guaranteed SLAs, they need a flexible, scalable optical transport
infrastructure – especially in the metro network – that efficiently supports
Ethernet and minimizes operational complexities.
Carrier Ethernet Transport (CET) is an architectural approach to building scalable transport infrastructure for supporting Ethernet and the evolution to NGNs* Carrier Ethernet Transport integrates intelligent WDM (ability to do multi-degree switching at wavelength and sub wavelength levels) with
Ethernet Tunnels, such as PBB-TE and T-MPLS .
* Carrier Ethernet Transport (CET) provides the simplicity and cost-effectiveness of native Ethernet with the reliability and power of WDM to deliver unparalleled flexibility, efficiency and cost savings
* Note that “Carrier Ethernet” comprises two distinct sub-segments: “Carrier Ethernet Services” and “Carrier Ethernet Transport”
Carrier Ethernet Transport is an architecture for NGNs based on wavelength networking. Services from both wireless and wireline access networks are simultaneously carried on a single network infrastructure. Three levels of embedded transport networking switching capabilities (wavelength, sub-wavelength, and Ethernet tunnels) provide a cost-effective transport network that can support services with guaranteed service level agreements (SLAs).
Another article in Converge! Network Digest suggests that CET is not the only way and there are alternative technologies available. The main advantage with CET is that it can reduce complexity compared to its main rivals.
CET offers the following direct benefits to carriers as they migrate to NGN:
- Maximizing the amount of Ethernet traffic that can be switched and routed without leaving the optical transport layer
- Reducing the load on expensive MPLS systems and precious LSPs
- Reducing the number of expensive optical ports required at metro/core hub points
- Providing a circuit-orientated transport model similar to SDH/SONET – which has great benefits from an OSS and operational perspective
Finally the article that made me curious about this subject was this article from Telecommunications Online (Part1 Part2) which is an interview of a Nokia-Siemens manager. Some interesting points as follows:
Telecommunications: You mentioned CET. Although it’s still an early concept, how are service providers responding to the idea at this time?
Bar-on: The perspective is very positive. CET is optimized transport Layer-2 carrier packet traffic. Traffic is growing tremendously. Sometimes you hear a number of 100 percent per-year growth in some carriers, but the average number would be about 70 percent. Everyone realizes the infrastructure needs to be packet-optimized. The way we present CET is it’s a combination of Ethernet and WDM. This has been positively received when looked at by carriers. You can have an argument as to what protocols to use, but CET is the next transport layer. Many carriers are looking for a migration from the current TDM- based infrastructure to a packet
optical-based infrastructure.Telecommunications: Outside of traditional enterprise services, there’s a lot of talk about using Ethernet for wireless backhaul. Albeit it’s still early, are your carrier customers investigating Ethernet for that application?
Bar-on: We do see a strong requirement from carriers doing wireless backhaul over Ethernet. It’s driven by two elements happening in the market:
1. Base Station Migration: The base stations themselves are migrating from TDM/ATM to 4G or Ethernet. We have the luxury in that we manufacture both the base station and the transmission equipment. We have a dedicated solution because we understand both ends of the market. It’s quite clear that Ethernet will play a role in 4G deployments.
2. Pseudowires: On the other side, carriers are looking to reuse their opex to carry 2G and 3G over Ethernet with Pseudowire rather than SONET/SDH networks. We see it mainly coming from competitive carriers that are trying to fight on the backhaul business to fight with traditional ILECs and PTTs. Having said that we at Nokia Siemens are providing a solution that addresses the current scenario where you have 2G, 3G, and a migration for 4G. What you see in both cases is this metro Ethernet network not only has to address not only Ethernet traffic, but also highly sensitive voice traffic over TDM. For that we believe that concepts like connection-oriented Ethernet can provide five-9s reliability for this kind of service. It’s no longer just about Ethernet access.Telecommunications: Earlier you mentioned Carrier Ethernet Transport (CET). One of the emerging debates to come out of the CET concept is the use of Provider Backbone Transport (PBT)/Provider Backbone Bridging-Transport Engineering (PBB-TE). How are these concepts resonating with the service provider community?
Bar-on: We’re seeing that everyone is interested in that and want to see if it’s real. Major carriers in the U.S. are very interested in the technology and are in a position to see that it’s real and it’s working. If you look at the cycle of technology, we are probably in the early beginning of the deployment of this technology at least in the U.S. market. We see other groups in Europe going quicker and are leading the camp here, but no one can really ignore this thing. Even if I look at the RFPs by major U.S. carrier out in the market some of them are including requirements for PBT/PBB-TE. If you think about this now and where we were a year ago that’s a major step.
Friday 9 November 2007
Moving towards IP Convergence
Service providers and enterprises need to differentiate to compete better, add new subscribers, and offer new advanced communications services and applications. For service providers, it means providing customers the services they want, when they want them, from anywhere they are, while consistently delivering a higher quality of experience. For enterprises, it may imply lowering network costs by providing new value and extending the lifecycle of existing network assets.
For carriers, this means being able to review current service offerings and expand or tailor them accordingly. Here are a few examples:
· Migrating from a new standalone service like IPTV and adding mobile TV and VoIP to create a triple-play offer;
· Migrating from fixed VoIP and adding mobility via Fixed Mobile Convergence (FMC); and
· Utilizing IMS to move toward a Service Delivery Environment (SDE), thus enabling access to which with the right underpinnings can be seamlessly blended together in a controlled and sophisticated manner to create a new, compelling experience that assures users service delivery.
1. Excellent support for multimedia applications. Improved connectivity means that devices can be assigned specific tasks; the number of devices required is less which makes installation, deployment, and learning an easier task.
2. A converged IP network is a single platform on which interoperable devices can be run in innovative ways. Since IP is an open standard, it is vendor independent and this helps in fostering interoperability and improving network efficiency in terms of time and cost. The ambit of IP convergence encompasses networks, devices, and different technologies and systems that can be operated on a unified infrastructure.
3. A converged IP network is easier to manage because of the uniform setup in which the system resources operate. Training users is easy.
4. An enterprise can achieve flexibility in terms of moulding its communication patterns to its management practices. This is a dynamic process that can be continually improved with collaboration from network partners. What this results in is the right information to the right person at the right time leading to improved decision making.
5. IP networks have proven to be remarkably scalable and this has been one of the prime reasons that even large enterprises have gone ahead with implementing IP. Applications that run on IP networks are available all over the world; in fact most new business applications include inbuilt IP support.
6. An IP convergent network is capable of making use of the developments in class of service differentiation and QoS-based routing. This leads to better utilization of resources and also allows for capacity redundancy to take care of an increase in the number of users.
7. A uniform environment requires fewer components in the network. Smoother maintenance and management result from this and in turn lead to improved processes. Affordable deployment results from the elimination of multiple networks operating in parallel and manageability improves. In a converged environment, fewer platforms need to be tested and gateways between networks are eliminated.
8. Business applications have different tolerance levels for transit delays, dropped packets, and error rates. IP architecture is capable of handling these so that the QoS reflects the requirements of the different applications.
9. Device integration has the potential to simplify end-to-end security management and at the same time make it more robust. Continuous development is taking place in field of security for IP data communication.