CPE Architecture: When Does All-IP Equal All-in-One? The telecom world is going All-IP. Meanwhile, service providers must select network-access technologies based on price, bandwidth, and geographic coverage for their evolving SME offerings. For customer premises equipment, multibox (modem + router + gateway) and single-box (IAD) solutions must be evaluated. So, what are the pros and cons?
Contents Introduction...3 CPE architecture options...3 One...3 Multi...3 Market Segmentation Economies of scale...4 Access Technology Trends...5 Logistics...5 One-box Solutions...5 Two-box Solutions...6 Service Evolution...6 Security Considerations...6 Equipment Cost...7 Conclusion...7 Authored by Ramon Felder Business Development Executive, Patton-Inalp Networks Edited by W. Glendon Flowers Product Marketing Manager Patton Electronics Co. Copyright 2017, Patton Electronics Company. All rights reserved. About Patton...7 About the author...8 Printed in the USA. 2
Introduction The telecom world is going All-IP. Such aspects as service quality, security, and reliability are under heavy scrutiny. Equipment vendors, service providers and consultants are developing and promoting solutions to these open and ever-evolving challenges. This article explores the topic from the perspective of service providers making crucial decisions about physical and functional network architectures on the customer premises. The available options for this architecture have a far-reaching impact on the logistics, flexibility and technological risks of All-IP deployments as well as the business plan for the venture. CPE architecture options Figure 1 provides a visual overview of the options for CPE architecture, shown as a set of schematic diagrams. There are essentially two basic approaches to the question of CPE architecture: one-box and multi-box. One The one-box solution integrates as many functions as possible into a single device. Such a device is commonly known as an Integrated Access Device (IAD). This means L1/2 transmission technology, L3/4 routing and security features as well as higher layer service functions such as media gateways and signaling are built into the same box. Multi Multi-box-solutions divide different network functions as described by seven layers in the Open System Interconnection (OSI) model among separate devices. The two most common ways to make that division are: 1. Include a router and transmission modem in one box, and provide a dedicated VoIP mediagateway or esbc in a second box. 2. one provides a simple transmission modem (acting as a bridge), while box two combines Layer-3 routing, QoS and security Figure 1 3
functions, and media-gateway or esbc functions. So, which approach is better? One-box or multibox? From the perspective of logistics, installation and management, the intuitive answer would seem to be fewer boxes is better. However, I would say it depends. Here s why. Market Segmentation Economies of scale First, not all customers are the same. Customarily the telecom market can be roughly segmented into three categories: residential, large enterprise, and small-to-medium enterprise (SME). Residential. The residential market is characterized by large volumes with a highly-standardized service offering. Service deployment, management and maintenance are designed for process-oriented procedures. Chipmakers and equipment vendors have developed highlyintegrated and extremely cost-effective solutions that focus on these requirements. Because the large volumes justify the up-front investment, one-box solutions that is IADs dominate this market segment. Large Enterprise. On the other end of the scale, large enterprises typically have proprietary business processes that demand customized network environments. Solutions typically require a project-oriented approach with unique system designs. Solutions providers combine best-ofbreed software, hardware and services to build an ALL-IP solution that satisfies the need. Commercially, equipment cost is less relevant than overall project pricing. The CPE setup may easily include four or five dedicated devices to provide such functions as transmission, routing, firewall, bandwidth-optimization, media gateway and signaling. SME. Between residential and large enterprise spaces, the SME market presents specific challenges. On one hand, system requirements and company sizes can vary wildly; on the other hand, there are relatively high volumes that call for process automation and standardization. For the SME environment, there are several arguments that favor a two-box or multi-box solution. Figure 2 4
Figure 3 Access Technology Trends Transmission technologies for network access and their availability are still rapidly evolving. This is true for wired and wireless solutions. In the SME space, asymmetric (ADSL, VDSL) and symmetric (SDSL, EFM) technologies are both relevant. On a roughly two-year cycle, improved standards emerge that increase the bandwidth capacity of legacy copper lines even further. More and more fiber deployments continue rolling out from city centers to suburbs and industrial areas. Meanwhile, wireless (4G, 5G) connections gain importance as fall-back, or even primary, Internet access links. This CPE architecture corresponds to the Modem & Router/Gateway column in figure 1 on page 3. Service providers must select which access technologies to employ in their SME offerings based on price, bandwidth, and geographic coverage. Rolling out a new access technology represents a costly, long-term infrastructure project. Service offerings, on the other hand, can evolve more rapidly. Under these circumstances it can make sense to separate the access transmission functions (OSI layer 1 and layer 2) from the routing and service functions (layers 3 to 7), provided by two separate devices. Such an approach eliminates dependencies, increases flexibility in designing services, and expands geographic coverage. Logistics Let s assume a service provider wants to offer business services for SMEs ranging from 4 to 30 voice calls with varying subscriber interfaces and over three different access networks. Let s consider how many box types the provider must purchase, stock, manage and maintain for each approach: one-box and two-box. One-box Solutions If IADs are deployed, the provider needs a different box for each case, as shown in table 1. Or, more abstractly, for n access technologies and m SME segments, the provider will need n x m stockkeeping units (SKUs). Table 1 Access VDSL EFM Fiber 4 FXS 1 7 13 8 FXS 2 8 14 2 BRI 3 9 15 4 BRI 4 10 16 1 PRI 5 11 17 SIP 6 12 18 5
Two-box Solutions Covering the same services and access technologies with a two-box solution, only n + m SKUs are required, as table 2 shows. Table 2 L1 2 Modem VDSL 1 EFM 2 Fiber 3 VDSL 1 EFM 2 Fiber 3 In view of these observations, it makes sense to implement the separation between access and services on customer premises, as well as in the provider network. This approach provides clear demarcation points between transmission and services (see figure 4). Service level agreements (SLAs) and management domains can be clearly associated regardless of whether the two domains are separate companies or separate divisions within the same company. L3 7 Router/ Gateway 4 FXS 4 8 FXS 5 2 BRI 6 4 BRI 7 1 PRI 8 SIP 9 Service Evolution Core expectations for an All-IP implementation include: All services over the same IP network Efficiency gains in deploying and operating the single IP network New, enhanced and flexible IP-based services As ALL-IP solutions proliferate and evolve, services become increasingly decoupled from the underlying network infrastructure. This decoupling can be viewed from a business as well as a technology perspective. The trend becomes more and more apparent as we consider recent developments, including: Hosted services OTT Providers, including Skype, Netflix, Apple, Whatsapp, and others White-label service platforms operated by overthe-top (OTT) service providers, branded by incumbents and access providers Figure 5 Security Considerations From a service-provider perspective, the additional IP/Ethernet interface between the two boxes on the customer premise may be considered a potential entry point for malevolent or unintended use (see figure 5). Two key points on that topic: Attacks on the carrier s network infrastructure are far more likely to come from the WAN than from a subscriber s site. The transmission network can be protected in such a way that the potential damage on Layer 2 is individual and local. Figure 4 6
Equipment Cost Transmission technologies, including Fiber, DSL, Cable, and others, are hardware-based by nature, and available as mass-produced chip sets. A pure transmission product, which acts as an Ethernet bridge with limited intelligence and configuration flexibility, can typically be produced at very low cost. A simple media converter, for example, that translates optical Ethernet to the ubiquitous RJ-45 CATx cabling typically costs some $20 to $40 when purchased in volumes. A simple VDSL modem bridge runs about for $50 to $60. A Layer-3 IP router that provides IP security, management and routing features requires more CPU performance, memory, and so forth, so it goes up in price. VoIP CPE devices also implement complex protocols and features that require a similar hardware infrastructure to deliver router functionality. In terms of pricing for a given performance level, the different CPE architectures outlined above may look like table 3. Table 3 suggests the following cost considerations: From a purely equipment-cost perspective the IAD is probably the least expensive approach When splitting functions into multiple devices, splitting off basic L1-2 transmission is a cost effectve approach (only one high-performance CPU/Memory/DSP unit) Total equipment cost does not reflect Total Cost of Ownership (TCO). Maintenance costs, operating costs, and logistics costs among others need to be evaluated and factored in. Conclusion Selecting between single-unit or multi-unit CPE architecture requires considering multiple factors, including provider network architecture and customer type (consumer, SME, large enterprise). As our intuition suggests, a one-box IAD solution typically offers the lowest equipment cost per unit. That is not the whole story, however. Upon deeper investigation, we discover that total cost of ownership (TCO) including logistics, operation and maintenance expenses is likely to be lower with a two-box solution, especially for SME subscriber services. For All-IP service providers that serve a range of SME segments, multi-box solutions can provide some important advantages: Simplicity lower number of SKUs to install, troubleshoot, operate, and maintain Best fit naturally suited for decoupled All-IP services Flexibility especially in the face of ever-evolving access technologies and IP services For SME service providers, the advantages of a multi-box solution, as summarized above, typically translate into a lower TCO with higher return on investment (ROI). Table 3 Architecture 1 Functions & Cost 2 Functions & Cost Total Cost IAD All-in-One $600 Not Applicable $600 Router Modem + Media Gateway L1/2 Modem L3 Router $500 VoIP SBC and/or $300 Gateway $800 Modem + Gateway Router L1/2 Modem $50 VoIP Gateway & Router $600 $650 7
About Patton Patton is all about connections. It is our joy and mission to connect real-world customer challenges with high-quality, right-priced solutions complemented by unrivaled customer service and technical support. Incorporated 1984, Patton has built everything from micro-sized widgets that connect "this-withthat," to carrier-grade Telecom gear that connects subscribers to service-providers. Patton's specialty is interconnecting legacy TDM and serial systems with new-generation IP-based voice, data, and multi-media technologies. Headquartered in Gaithersburg, MD, USA, Patton equipment including VoIP, Ethernet extension, and wireless router technologies is up-and-running in carrier, enterprise and industrial networks worldwide. Patton works in connection with a growing network of technology, business, and sales-channel partners. To connect with local-market requirements, Patton operates training and support centers in Switzerland, Hungary, Lebanon, Australia and the USA. Patton Let's Connect! About the author Ramon Felder Business Development Executive, Patton-Inalp Networks Ramon Felder is the business development executive for Patton-Inalp Networks in Switzerland. Previously he has served Patton-Inalp over 18 years in different roles as CEO, COO and product manager. Mr. Felder graduated in 1996 from the Swiss Federal Institute of Technology in Lausanne and holds an Master degree in Business Administration from the University of Rochester. About the editor W. Glendon Flowers Product Marketing Manager, Patton Electronics Co Glendon is responsible for creating corporate marketing and technical content including press releases, web copy, white papers, case studies, educational and tutorial pieces as well as other publications. He serves as editor in chief for Patton's email newsletter and other outbound communications. He holds a Bachelor of Science in Computer Science from UMUC and a Bachelor of Music in percussion performance from UMCP. 7622 Rickenbacker Drive Gaithersburg, MD 20879 USA tel: +1.301.975.1007 fax: +1.301.869.9293 web: www.patton.com email: marketing@patton.com Document: 07M-CPEARCH-WP