Home EMEAEMEA 2007 Convergence through hybrid networks

Convergence through hybrid networks

by david.nunes
Yossi Ben-Harosh
Itshak Aisner
Issue:EMEA 2007
Article no.:10
Topic:Convergence through hybrid networks
Author:Yossi Ben-Harosh and Itshak Aisner
Title:(Yossi Ben-Harosh) CEO and President and (Itshak Aisner) VP Product Management
Organisation:Telrad Networks
PDF size:224KB

About author

Yossi Ben-Harosh is Telrad Networkís CEO and President. Mr Ben-Harosh has two decades of experience in telecommunications, operations and management, including over 16 years at Telrad. Prior to serving as CEO, he was Division President of Global Operations, responsible for all Telrad Operations Infrastructure and R&D of OEM/ODM products and solution. Previously, Mr Ben-Harosh acted as Operations Manager in the areas of: Global Supply Chain Management; New Product Introduction & Manufacturing; R&D Engineering Support; and, System Integration Fulfillment. Prior to joining Telrad, Mr Ben-Harosh was a project manager at TEVA Pharmaceutical Industries Ltd. Mr Ben-Harosh holds an MBA from Bar Ilan University and a BSc in Industrial Engineering & Management from Ben Gurion University.

Itshak Aisner is the VP of Product Management at Telrad. Mr Aisner has more than 20 years of experience in telecom, as a SW designer, R&D team leader, R&D department manager and product manager. Mr Aisner has been a Product Line Manager and VP Product Manager for a variety of products based on diversified technologies.

Article abstract

Despite all the publicity about the transition to IP-based, fully converged networks, the reality is somewhat different. Operators are not changing over directly to softswitches and IP networks but using their existing TDM, time-division multiplexing, copper-based networks to evolve gradually into full-scale IP. Today, IP is supplementing TDM. In fact, despite the spin vendors try to put on it, there is evidence that conversion to more advanced networks is driven more by normal replacement cycles than by the technology itself.

Full Article

A lot has been happening in the telecom world in terms of access technologies, as operators continuously look for ways to provide more bandwidth and services at the lowest possible cost. On the other hand, the subscribers donít care how access is provided, as long as it is smooth and easily accessible. Carriers had hoped that IMS, IP Multimedia Systems, architecture would, ideally, resolve many of their access technology issues, since a converged core will allow applications and services to be independent of the access methodology. However, in practical terms, true IMS deployments are still years off, both technologically and in terms of the supporting business case. Furthermore, IMS intends to provide a converged core control layer and aims to deal only with signalling, control and management methods – including the core interface to a variety of access technologies. IMS does not apply to the transmission networks or most of the payload traffic. On the ground, what we are seeing in practice are hybrid and transitional networks, with packet-based networks combined with existing legacy switched networks. Operators are gradually increasing traffic over IP, while continuing to leverage their legacy TDM, time-division multiplexing, infrastructure to maximise return-on-investment, ROI. For carriers to achieve this goal without compromising quality, the gap between TDM and IP must be bridged as smoothly as possible. Thus we see an increasing number of cases where a TDM core network expands its access through IP channels, and vice-versa. There are several key areas in which this can be implemented: ï ethernet over copper; ï voice over WiMAX; ï cellular backhaul over IP; and, ï making the transition from traditional switching to softswitches. In addition to cost incentives, risk-aversion is a major incentive for operators to make a gradual transition. Simply speaking, todayís networks are fully functional, fully configured and extremely complex. No network operator wants to make major changes to the infrastructure because of the risk of degrading existing levels of service. Customers expect to pick up the phone and hear a dial tone. While there is more tolerance for data and for mobile voice, the level of tolerance for wireline voice service is relatively low. Therefore, incumbents are always going to select gradual transitions to new technology in order to avoid mistakes or even temporary loss of service. A gradual transition also allows the operator the time to re-train existing staff on the new technologies. Ethernet over copper We see increasing demand for wireline Ethernet access in locations with a heavily established legacy PDH, Plesiochronous Digital Hierarchy, infrastructure, particularly among small and medium businesses, there can be great value in a hybrid solution. Rather than laying down new cable to each destination, solutions are now available that let the carrier place a small box at each end of the copper line to offer Ethernet access at lower cost and with faster deployment. The main driver for Ethernet over copper solutions is cost reduction. Where the operator owns the infrastructure, or where leasing of E1 or T1 lines is cost-effective, service providers are not replacing the infrastructure. Still, much of the network is currently moving towards IP, and much of the traffic at the edge is in IP format. Itís natural for operators, then, to seek Ethernet over copper solutions to maximise the return on existing infrastructure at the same time they upgrade the networks. In applications where the distances are short, traffic is very high or leased lines are expensive, the move to fibre is going to happen more rapidly. IP wireless backhaul Even in cases where access through TDM remains, carriers can greatly expand access by shifting more of their backhaul for GSM, CDMA and related technologies to a core IP network. By reducing the amount of T1/E1 cable needed to transport their core traffic, mobile service providers can reduce their capital expenditures and gain greater flexibility whilst expanding their cellular access, both in terms of sites as well as bandwidth. Today, as people start to use their mobile devices for email and for additional services, there is a rise in the amount of IP traffic running over the wireless networks. In most areas, web surfing and email are not yet mass-market mobile applications. However, with the implementation of fast networks such as EVDO, Evolution-Data Optimized, – a wireless broadband access standard, and HSxPA, High Speed – Downlink or Uplink – Packet Access) there will be a huge increase in the amount of IP traffic over the networks. While the core networks may remain TDM based for quite a while, the backhaul networks in some areas are rapidly moving towards IP-based networks. Other areas are using microwave or other technologies for backhaul. The universal trend among established operators is towards hybrid networks. To keep costs down, all operators need to preserve the existing infrastructure while adding new networks. WiMAX VoIP is another technology that is rapidly growing in popularity, attracting tech-savvy users from the developed world, as well as many enterprises. VoIP is an interesting way to expand telephony coverage to rural and developing areas, through voice over WiMAX wireless broadband. Many carriers in these difficult-to-service areas have particularly strict budget constraints, because of the low average revenue per user, ARPU. Furthermore, initial WiMAX deployments to date have been small – usually just a few thousand users. Ideally, these operators would want to leverage their existing TDM core. Operators need to consider both installations of the IP network and the WiMAX base station, as well as their smooth interoperability with their TDM core. Recently developed technology enables carriers to accomplish this – expanding coverage through WiMAX with high quality and full features (caller-ID, call waiting, emergency services, etc.) without the need for expensive softswitches, making WiMAX a more viable access method in these regions. Typically, an incumbent operator using WiMAX for access deploys the IP network, the WiMAX base stations and end-user equipment before moving on to specific applications such as voice. However, for rural areas where there is no other access method, voice is a crucial application. In such cases, operators can install an access gateway that allows translation of the IP to TDM protocols. This allows existing digital TDM switches to provide all voice provisioning, services and management, while the WiMAX network provides voice access. Incidentally, this is identical to the path that cable operators follow when offering voice services. Before deploying a softswitch, TDM switches through media and signalling gateways enable the initial subscribers. This ensures that cable operators have a critical mass of voice customers before making the investment in a softswitch. From digital TDM to softswitches Incumbent operators are gradually upgrading their systems to IP-based softswitches. The existing digital TDM switches are extremely reliable, fully configured for a range of services and applications, and they represent a huge investment by the operators. For these reasons, the implementation of softswitches is happening gradually. In fact, in many cases, the replacement of existing switches with softswitches is exactly in line with the regularly scheduled replacement cycle for switches, rather than technology-driven changes. Therefore, on the ground, operators are simply building on and expanding their existing networks, without overhauling the basic network. The IP networks are coming in as supplemental to the existing TDM networks. It is not likely that we will see operators initiating a shutdown of existing, working switches just because of the new technology, although the vendors would like to present the change in that way. Within this world of hybrid networks, there will continually be interoperability issues that need to be solved through technologies that allow the different networks to function as a single network. Such technology includes gateways, management systems and transport solutions for heterogeneous networks.

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