CCAP: The Evolution of a Network

Transcription

1 SPECIAL REPORT CCAP: The Evolution of a Network By Monta Hernon Sponsored by

2 Special Report CCAP: The Evolution of a Network The emergence of over-the-top (OTT) streaming services like YouTube, Hulu and Netflix, combined with the prevalence of mobile devices accessing the network is creating a surge in data demand especially as consumers are becoming more accustomed to the idea of content anytime, anywhere. Current networks still have substantial bandwidth capacity potential that can be further enhanced through key changes-- conversion to all-digital lineups to reclaim spectrum, or utilizing switched digital video, for example. However, to provide enough bandwidth to support future growth, operators are putting the cogs in place for an eventual evolution from MPEG-based video delivery to IP video transport. In the meantime, one of the limiting realities of today s networks is that video and data infrastructures are deployed across separate platforms. Cable modem termination systems (CMTSs) are needed to provide services such as Internet or voice over IP, while edge QAM (quadrature amplitude modulation) technology is the format by which digital video channels are encoded and transmitted. Suffice it to say, headends are crammed with large racks of units that use a lot of power and occupy a lot of real estate. It stands to reason Figure 1. CCAP will help operators meet bandwidth demand driven by OTT streaming and multiscreen video. that eliminating duplicate engineering efforts would increase efficiency and reduce space and power requirements. With both at a premium, doing so has become a strong driver for cable operators. Enter the Converged Cable Access Platform. CCAP proposes to combine edge QAM technology and the CMTS technology in one device. The unified platform will support 2 BTR Special Report: CCAP: The Evolution of a Network sponsored by

3 CONNECTING PEOPLE, NETWORKS, AND TECHNOLOGY CommScope has played a role in virtually all the worldʼs best communication networks. We create the infrastructure that connects people and technologies through every evolution. Our portfolio of end-to-end solutions includes everything our customers need to build high-performing wired and wireless networks CommScope, Inc. All rights reserved.

4 universal carrier channels for both video and DOCIS, and the resultant integration of broadcast and narrowcast QAMs as well as DOCSIS 3.0 downstream and (eventually) upstream interfaces, will maximize spectrum and eliminate the need for most of the combiner functionality in the headend. Specifically, estimates show a fully converged CCAP platform could provide as much as 50 percent savings in rack space and 60 percent in power costs. It is, indeed, a solution that can save space and power, while providing immediate assistance in meeting bandwidth demand. Yet, CCAP also has the potential to be a key driver for the industry s evolution to an all-ip world. CCAP: A Brief History The concept of combining video and data into one platform was not born as CCAP. Operators had the idea on the back burner for years, until two dominant tracks emerged: the Converged Multiservice Access Platform (CMAP), which was backed primarily by Comcast, and the Converged Edge Services Access Router (CESAR), which was promoted by Time Warner Cable. Both CMAP and CESAR had the same end goal, but varied on the finer points, like service group size, for example, and whether encryption should be integrated or stand alone. In June 2011, CableLabs blended CMAP and CESAR, dubbing the new architecture CCAP. The differences were settled by allowing for varying service group size, accommodating multiple interfaces, and supporting a modular and integrated approach. The first CCAP products were announced at Cable-Tec EXPO in Lab and field trials occurred throughout 2013, with the first deployments appearing about halfway through the year. Implementation Although CCAP calls for full convergence of video and data, this is not happening from day one. Operators are either entering the CCAP arena from the CMTS side of the spectrum or from the Edge QAM side. The major CMTS vendors each have introduced a CCAP-ready chassis that performs the function of a CMTS, with plans to integrate edge QAM elements later. While operators are saying they would not pull out equipment that is still serving them well, they are opting for these CCAP-ready devices when it is apparent a legacy CMTS device can no longer meet demand. The trigger point seems to be a need for more than eight bonded or non-bonded downstream DOCSIS channels per serving group or node. Instead of installing another stand-alone CMTS, they are deploying a CCAP chassis which offers four to six times the density of a typical CMTS platform at a lower cost per QAM. Coming at CCAP from a different perspective, Edge QAM manufacturers are introducing chassis built around a dense Edge QAM with the idea that CMTS functionality will be added down the road. Operators currently require approximately 28 QAMs per service group or node. This is projected to increase over the next few years especially as the deployment of more narrowcast services, like VOD, SDV, and commercial DOCSIS data continues to grow. 4 BTR Special Report: CCAP: The Evolution of a Network sponsored by

5 CCAPs are cheaper and better. Vendors are not developing new CMTS and new CCAP platforms, because they think operators may buy either. All vendors are developing CCAP, because as any MSO needs to expand, it will do so with CCAP. Jorge Salinger, VP of access architecture, Comcast. Traditionally, adding more QAMs has meant installing new so-called pizza box units in the headend, and more equipment equals more rack space and more power. On the other hand, the Edge QAM components of the new CCAP platforms are extremely dense. However, this density is pay-as-you-go. An operator can start out with a small number of QAMs and increase as necessary using a software key and a predefined price per QAM. Yet, moving forward in a converged world, density is not the only thing that matters when it comes to the Edge QAM. Looking at the traditional design once again, each service-- linear broadcast, SDV, VOD, DOCSIS, etc.--has required a separate block of pre-configured QAMs. Multiple chassis have to be hardwired to provision and deliver these blocks in a specified slot of bandwidth within the 1 GHz spectrum. To re-provision the blocks, the hub or headend has to be physically rewired. This hampers the ability for operators to quickly roll out new CommScope: CCAP for Today and Tomorrow Recognizing that CCAP is not just another box, but an industry evolution, CommScope designed its Converged Services Platform (CSP) to address the most urgent requirements of operators--increased density, lower power, less real estate-- but also to adapt to and even drive the technological advancements of tomorrow. Our vision is to ride with cable operators in terms of what they want, but also to figure out where they need to be. We want to skate to where the puck is going and the puck is going toward an IP to the home architecture, Sunil Frida, director, global business development, CommScope, said. CommScope feels that the downstream CCAP race is still being fought in the sense that even the operators do not necessarily know what their next step will be--docsis 3.1, EPON, Remote PHY, etc. The CSP, therefore, was built to serve multiple endpoints, depending on which direction the operator chooses. There are pros and cons to each approach so it s still unclear which architectures operators will use and which they will skip. We wanted a solution that was the most flexible and didn t limit operator s options so we built a CCAP product that supported a different blade for each architecture, Frida said. The CSP was launched as an ultra highdensity wideband universal Edge QAM. A 9-RU chassis supports up to 12,800 continued on page 6 5 BTR Special Report: CCAP: The Evolution of a Network sponsored by

6 services or alter QAM channels in response to service group changes. In the new CCAP chassis, Edge QAM vendors are using universal QAMs, meaning the MSO chooses what service they want and the software assigns a QAM. No constraining blocks. Instead, any channel can be provisioned individually for any video, voice or data service based on need instead of available spectrum. Looking to the Future While CCAP deployment is underway, operators and vendors already are looking to the future. There are a number of other technologies and architectures being discussed that could affect the way CCAP is implemented. Distributed architecture, also known as Remote PHY or Virtual CCAP, for example, would take the media conversion component out of the CCAP chassis and place it in the field, most likely at the node. Converting the MPEG video to QAM further out in the HFC network, could have several major effects. First, by taking the intelligence closer to the customer, the service group can be smaller and the operator can become more targeted with things like advertising. Second, distributed access essentially slices the CCAP chassis into two parts and connects them with a Layer 2 Ethernet pipe. This eliminates the need for an expensive analog transmitter in the headend. An Ethernet transmitter, costing a couple hundred dollars instead of a couple thousand dollars, can be used. And third, remote PHY stands to improve the modulation error (MER) limitation and, therefore, the link from the headend to the customer premise. Operators believe Remote PHY could enhance performance, density and operational efficiency as they move to higher orders of downstream QAMs and a 14-RU chassis supports up to 28,160 downstream QAMs, all of which can be configured for any combination of DOCSIS, broadcast video, SDV, or VOD and can be assigned at any frequency across the 1GHz spectrum. Our QAMs are universal...the growth curve might be steeper on data QAMs than video QAMs,...We sell the QAM and the operator decides how to best deploy it, Frida said. The next major iteration of the CSP is an optical line terminal (OLT) with Gigabit Ethernet and 10 Gigabit Ethernet Passive Optical Network line cards. Operators can serve the commercial data services market immediately, but also look toward the rollout of technologies like DOCSIS provisioning over EPON, 10Gig EPON, and EPOC. PON as a standalone has gained a lot of traction with cable operators today. We see the ability to migrate from QAMs to native IP over PON as really compelling so, we designed our CCAP solution to support PON blades. Today, operators can use our standalone PON for business services and at some point evolve to residential services over either the standalone or CCAP platforms, Frida said. In the meantime, replacing separate pizza box units for broadcast, VOD, SDV, data, etc., with one CCAP device, has made redundancy extremely important. CommScope says its CSP solution is fully redundant, from the power supply and ports, to the line cards and processing components. Our box has been built from the ground up by a bunch of guys that came from the telco side, where redundancy has been a huge requirement (because of lifeline services)...everything (in the CSP) is redundant so that if anything goes down, it switches over quickly, Frida said. 6 BTR Special Report: CCAP: The Evolution of a Network sponsored by

7 modulation permitted by DOCSIS 3.1. They caution, however, that any implementation of Remote PHY needs to be transparent to back office and CPE devices. CCAP and Remote PHY are complementary, with the latter requiring an Ethernet port on the CCAP chassis. Remote PHY specifications are in progress, and the expectation is they will be Comcast Deployment Underway The largest operator in the United States, Comcast Eventually as we deploy new service groups and has played a major role in the development of we are using CCAP devices, (DOCSIS and video CCAP and is now in the process of widely groups) would naturally align. In retrofitting, we deploying CCAP devices. Jorge Salinger, VP of wanted to minimize the changes in the network access architecture, declined to confirm current to make the migration easier, Salinger said. numbers, but did say the transition is occurring in When Comcast will complete the migration places where more QAMs are needed. of its network to CCAP is unclear. Salinger The (process) is being triggered by normal compared it to the rollout of DOCSIS 3.0, growth...the need for more DOCSIS QAMs, which started four years ago and is just more video QAMs or both Either of these reaching the point of completion. events is triggering the deployment of CCAP It will be the same with CCAP. It will equipment just like it would have resulted in take a while to deploy. We will only replace more CMTS equipment before, Salinger said. equipment when we need capacity and that In places where Comcast has an integrated takes a while, Salinger said during the CCAP CMTS and needs to go from eight to 16 breakfast at the Cable Show in June. DOCSIS QAMs, the company is migrating to More recently, he assured that CCAP is here the CCAP platform, which it intends to use to stay. It not only offers the benefits of higher for integrating video. In the places where density, lower cost, and less rack space, but Comcast has deployed a modular CMTS is directionally aligned with the migration to architecture, when it needs more DOCSIS IP video. A CCAP platform can migrate any or video QAMs, it will utilize a high density video QAM to a DOCSIS QAM, which is what Edge QAM platform that can support both needs to be done in order to provide IP video. video and data, Salinger said. That is why vendors are developing (CCAP Comcast s CCAP deployment began after a seven platforms) and MSOs are deploying them. month trial, that included working out integration, CCAPs are cheaper and better. Vendors are management and configuration issues. The not developing new CMTS and new CCAP company wanted to avoid service group platforms, because they think operators may alignment by using a feature called replication. buy either. All vendors are developing CCAP, Making the service groups the same would because as any MSO needs to expand, it will mean changes in the way the network is wired. do so with CCAP, Salinger said. 7 BTR Special Report: CCAP: The Evolution of a Network sponsored by

8 completed by the end of the year, with devices coming on the market in Ready for DOCSIS 3.1 DOCSIS 3.1 is also coming soon. CableLabs released the specifications last fall, and products are expected either later this year or early An included update to the PHY layer could bump up spectral efficiency by 60 percent and orthogonal frequency division multiplexing (OFDM) will narrow the QAM carrier from 6 MHz to 25 khz-50 khz wide. The component of 3.1 that will perhaps have the most impact, however, is a new method of forward error correction (FEC) called lowdensity parity check (LDPC). The resultant higher resilience to noise, will mean a plant that previously could run 256-QAM will be able to run 1024-QAM. The improved MER offered by Remote PHY might provide the headroom for 2048-QAM or possibly even 4096-QAM. The downstream line cards in the new CCAP chassis are being implemented with field programmable gateway arrays (FPGA) that are upgradable to DOCSIS 3.1. Additionally, the initial CCAP platforms are capable of supporting at least two OFDM blocks of channels, necessary for DOCSIS 3.1. PON Today, EPOC tomorrow A passive optical network (PON) uses unpowered optical splitters to enable a single optical fiber to serve more than one premise, in a point-to-multipoint configuration. CCAP chassis that include PON blades allow operators to offer Ethernet PON services right away for high-end business customers, and to roll out IPbased residential video services in the future. Figure 2. CCAP has the potential to be a key driver for the industry s evolution to an all-ip world. In fact, there is another standard being developed at the Institute of Electrical and Electronics Engineers (IEEE), that would make it easier for operators to do so. The aptlynamed EPON protocol over coax (EPOC) would allow Ethernet packets to be delivered over coax for the so-called last mile to the home without requiring an IP set-top box. With PON compatibility in the CCAP chassis, therefore, an operator is prepared not only for EPON, but for EPOC as well. The bottom line is that CCAP is an architectural change for operators that will provide bandwidth relief in the short term as well as increased channel density, a lower power requirement and reduced headend footprint. However, CCAP also has the potential to drive the evolution to IPbased video delivery. To do so, the platform must be flexible enough to accommodate whatever technology an operator chooses to get there. Monta Hernon is a collaborating writer for BTR 8 BTR Special Report: CCAP: The Evolution of a Network sponsored by