There is evidence to suggest that during the past year, carriers of all sizes are beginning to lean towards dismantling or significantly consolidating their TDM Class 5 assets and transition towards NGN Networks. A crucial and often overlooked aspect of the telecommunication network is the access network. There are different approaches for connecting the access network to the core network and to migrating the V5 TDM based legacy access network to the IP based network. One approach is by introducing a Core Access Gateway that connects remote TDM DLCs to an NGN Softswitch. This article will outline the benefits of extending NGN services to the access network. In addition we will demonstrate why the Core Access Gateway provides the preferred solution for V5.2 TDM Access Networks.
Class 5 Replacement Benefits
TDM Class 5 switches were supplied by traditional voice vendors. Many of these circuit switches are reaching end-of-life status or require software/hardware upgrades to meet technical and/or regulatory requirements, such as local number portability, or lawful intercept.
Designed to replace these aging and monolithic circuit switches, Class 5 alternatives can sometimes be purchased and deployed at a lower total cost rather than purchasing software upgrades from an incumbent equipment maker. Faced with the prospect of making additional investments in aging and inefficient equipment, carriers are turning to Class 5 alternatives. When the first of the Class 5 alternatives emerged a few years ago, the most attractive feature the platforms offered was a significant reduction in footprint and electricity power consumption — as much as 90% in some cases — and a migration path to packet-based voice technology. Rural and independent carriers have quickly begun to realize that they must respond to competitive incursions into their customer base from wireless carriers, MSOs, and Voice over Broadband (VoB) players.
Significant cost savings can be achieved by C5 migration into the carrier NGN:
- Operation and maintenance of one converged network for Data and Voice services
- Footprint saving will result in substantial real-estate cost savings
- Substantial electricity bill savings
- Delivery of new services is more efficient in terms of time and cost
- Service providers will benefit from increased freedom to select multiple vendor solutions
Alternatives for Access Network Transition to IP
Operators deploying NGN must consider the installed base. Indeed, the migration from the legacy network is one of the greatest challenges facing operators. One of the main requirements of carriers migrating their Class 5 infrastructure to VoIP is the ability to reuse all of their access equipment and infrastructure, without disrupting POTS users.
In the next few sections we will concentrate on the carriers’ alternatives for connecting the access network to the NGN Softswitch.
IP in the Loop -Voice Over BroadBand (VoBB)
In this approach, voice migration cannot be considered complete until all legacy telephones have been replaced by IP Phones or multi-media devices (or by installing an IAD at customer premises). This process of moving subscribers to a new device may take decades. Operators will, in fact, begin by offering VoIP to subscribers as a second line service bundled with broadband services, while leaving the existing POTS service intact. ITSPs, MSOs and new emerging service providers (like Vonage/Skype) that do not have a traditional access network will prefer to adopt this path. This fits end users who are keen to make use of new applications as soon as they become available, the “early adopters”.
Core IP Solution- Core Access Gateway
At the other end of the spectrum are the end users who are disinterested in the latest “gizmo” and expect to use their existing phone for an entire lifetime. ILECS, IOCs and rural POTS telephony service providers will choose to use a cost-effective Core solution in which the end user will not “feel” any change.
The Core Access Gateway aggregates E1s/T1s which stem from multiple DLCs, and converts them to IP. The PSTN access protocols are known as TR-0008 and GR-303 in North America and V5.1/V5.2 in the rest of the world. They can be observed in the figure below.
Benefits of the Core Access Gateway Solution
For carriers that have a significant size of legacy standard DLC equipment, upgrading existing access equipment (DLCs, DSLAMs, Muxs, RSUs, WLLs) is not an option due to the enormous cost (high installation costs), high risk and disruptiveness.
Placing a gateway from the DLC to the Softswitch is less disruptive and can be implemented step by step - migrate a span at a time. This way operating companies can gradually retire Class 5 (or capital investment on Class 5) without disrupting current circuit-switch voice users.
The Core Access Gateway solution is clearly most beneficial in a scenario where the V5 access network already exists.
AudioCodes Solution
AudioCodes provides V5.2 Access Core Gateway functionality on a standard MediantTM 3000 highly available gateway. These platforms are equipped with the high density TP8410 blades, providing a carrier grade, cost–effective V5.2 Access Gateway solution.
The Mediant™ 3000, equipped with the high density TP8410 blade is a compact, cost-effective media gateway platform targeted towards low-mid-sized carrier deployments, supporting from 16 up to 63 E1s, multiple V5.2 Interface groups, all-in-one TP8410 Blade (1+1x Redundant Blade configuration is also available), providing telephony services for up to 20,000 lines. At 2U, the small footprint of the Mediant™ 3000 is especially attractive for central office locations where space is at a premium or for installation at remote sites, as depicted in the figure below.
Summary
With this compact cost-effective Mediant™ 3000 V5.2 Access Gateway platform you can expand the Class 5 NGN service to the last mile, and benefit from its achievements, both in capital investment savings and reduced operational costs.
The AudioCodes V5.2 access solution allows you the flexibility to migrate and extend NGN into the access network.