How to connect your TDM and packet networks into one!

With smartphones in every pocket with applications abound,  ultra-fast home or business broadband,  it’s  easy to forget the once cutting edge of Time Division Multiplexing (TDM)  technology. The thirst for unlimited applications and increasing bandwidth are  best quenched by leveraging streamlined packet technologies.

In the age of stressed revenues and associated margins, TDM  is something that’s both a benefit and a burden for network operators. Higher  revenues are a welcomed blessing and curse, as the decades-old TDM equipment used  to provide the service, has or is nearing end-of-life. The pressure to retire  legacy networks isn’t going away, so how can operators continue to cost-effectively  maintain two separate networks? Well, the short answer is they shouldn’t and  don’t have to, if they leverage the very latest modernization solutions available  today. But before I get to network modernization, let’s take a short walk down  TDM memory lane.

TDM Networks

For the last few decades, many TDM-based technologies were  used to deliver switched voice, video, and data services including Digital  Access and Cross-connect Systems (DACS), Add-Drop Multiplexer (ADM), and  Multiservice Provisioning Platforms (MSPP). Although these technologies served  their customers very well, they are definitely showing their age.

Typical TDM Network

What is a DACS?

DACS, or more commonly referred to as Integrated Services  Digital Network (ISDN), is used to digitize voice, text, e-mail, and video data  over copper pairs between the customer and switching office. Over the years, a  major part of the network aggregated and transported private-line services  (PLS) or copper-based pairs to the Local Exchange Connections (LEC) and then to  the switching or data center. Each PLS is continuously connected, and where  necessary, LEC, tandem offices, and Inter-exchange connections (IXC) is used to  connect to the digital fiber-optic network. DACS preforms low- and high-level  grooming (3/1, 3/3).

What is an ADM?

Private or leased-lined services use ADMs as the on/off ramp  to the high-speed network. ADM rings of various speeds, and vendors, multiplex  multiple customers into a single beam of light, carried to the local  office/exchange, demultiplexed, and electrically terminated to a patch panel  for connection to the high-speed network. While popular, these services don’t cost-effectively  scale with the only option of going from T1/E1 to T3/E3. With only multiplexing,  ADM connections did not utilize all the bandwidth transmitting empty  time-slots.

What is an MSPP?

Going several steps forward, Multi-Service Provisioning  Platforms (MSPPs) were developed to consolidate TDM, packet, and optical  services. Common electrical interfaces were supported for private-line, data  and optical – topping out at 10Gb/s OC-192/STM-64 for transport. Both High-Order  (HO) and Low-Order (LO) (VT1.5) grooming were supported, enabling service  grooming and consolidation. In order to support data services, many different  encapsulation protocols, including Generic Framing Procedure (GFP), Packet over  SONET/SDH (PoS), Frame Relay (FR), Multi-Link Frame Relay (MLFR), and Point-to-Point  (PPP) were used to deliver end-to-end data services.

The TDM conundrum

The increasing cost of maintaining a separate TDM network is  becoming more of a burden. Over the years vendor consolidation, often followed  by manufacturing discontinuation of complete product lines, has left very few,  if any, options to fill empty equipment slots or maintain old hardware; worse,  legacy products require different types of control software that can be hard to  update and impossible to integrate with new solutions. Letting these platforms  continue to rust is not viable. It also increases risk, because network  providers may not have the ability to update the legacy security software to  protect the network against modern, sophisticated security attacks.

Leaving TDM equipment to rust, is not a viable option.

Addressing TDM  Network Inefficiency, TDM-to-Packet, and Service Modernization

For today’s data transport needs, network providers use packet  optical networks to offer IP and Ethernet services for residential enterprise  customers to offer broadband, voice, cloud-computing, mobile backhaul, data  center interconnects, and other network services.

While market forces and technology benefits are driving the  shift to packet networking, running parallel networks to meet both TDM and  Packet requirement is too costly and complicated. For operational and business  efficiencies, network providers need a data transport system that can provide  legacy and packet networking services on a single, future-oriented, scalable  foundation. One that supports both small and large network providers transition  DACS, ADM, and MSPP services to packets and deliver broadband services to the  market.

To support TDM services in a packet network, you need to emulate  the circuit using Circuit Emulation (CEM) and transport that CEM with  Pseudowire Emulation Edge-to-Edge (PWE3). Three CEM types are used:  Structure-Agnostic TDM over Packet (SAToP), CEM over Packet Switched Network  (CEMoPSN), and Circuit Emulation over Packet (CEP). SAToP and CEMoPSN  encapsulate payloads on low-speed services, while CEP encapsulates payload  based on Virtual Connections (VCs). All of these encapsulations interoperate  flawlessly with PWE3.

Network Consolidation

Network operators can evolutionize their packet network with  Ciena’s TDM-to-Packet networks solutions. Just a few ports are needed at a  given service end-point and smart Small Form-factor Pluggable (SFP) devices  make use of PWE3 to create a virtual, dedicated lane for TDM business services.  Or when more ports are needed Ciena’s 3926m Service Delivery Platform future-proofs service delivery, from TDM to virtual.

Ciena’s 6500 Packet Transport System (PTS) was purposely  built to address TDM services scale and flexibility, enabling TDM-to-Packet  migration and Ethernet services. With two platforms, 8-slot and 14-slot, the 6500  PTS offers network providers DACS and MSPP replacement, packet  switching and transport, Headend ADM ring consolidation, TDM to Ethernet  Gateway, and network modernization. The 6500 PTS stands out from the pack by  offering up to 5x lower power, 10x space  saving, and 4x more TDM CEM capacity than competing platforms.

While, Blue Planet’s open and  extensible architecture, Blue Planet Manage, Control, and Plan (MCP),  can be used to provide end-to-end lifecycle management and operations. Don’t  know where to start, Ciena can help there too. Start with a network audit and  topology discovery, Ciena  Insights Services have in-house expertise to engineer or plan  migration and modernization TDM networks.

So, get ready to connect all your network services across a single  network, providing a migration to the future for legacy TDM business service,  and enabling new opportunities.

Ask us how Ciena helps Evolutionize  Your Packet Network.