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CCAP: More than just box replacement

Sun, 04/29/2012 - 9:22pm
Jorge Salinger, vice president of access architecture, and Ty Pearman, director of access engineering, of Comcast

Early lessons from Comcast's operational readiness trial.

Many people have by now heard of the CCAP, so here is a quick summary of what CCAP is and does:

  • CCAP stands for Converged Cable Access Platform.
  • It combines the functions of the CMTS and edge QAM into a single platform.
  • It eventually implements all narrowcast and broadcast QAMs.
  • It offers many operational features for scaling an all-digital network.

CCAP DS Port AssignmentsFigure 1 shows how a single port of a CCAP includes all of the QAMs for a given service group, including MPEG-TS for broadcast and narrowcast video services, and for DOCSIS applications.

CCAP was specifically architected to support growth in the number of QAM channels used for narrowcast services, such as video-on-demand and switched digital video, the expansion of HDTV content, and the availability of channel bonding in DOCSIS 3.0 to support newer and higher-bandwidth data services.

And as MSOs continue to reduce the size of service groups to make more efficient use of their networks and deploy advanced services such as IP-based video and network DVR, even more QAM modulators are needed. CCAP devices will provide the necessary QAM-per-RF-port and port-per-chassis density needed to support this growth, while requiring less space and power than currently available equipment, reducing capital and operational costs, and simplifying operations.

There are many reasons for CCAP’s success amongst MSOs, even before the equipment becomes available. The key ones are included in Figure 2.

Key drivers for CCAPBut supporting the growth in the use of narrowcast QAMs is the key reason. Figure 3 depicts this expected growth.

Narrowcast growthRedefining operations
CCAP has the potential to redefine how operators deploy, scale and manage edge network access.

Video QAM and CMTS equipment is currently deployed across a multitude of separate platforms, and edge capacity is managed manually through multiple tools and is configured mechanically by connecting the various wires to the signal combining network, which is operationally inefficient.

One aspect of the CCAP is that it will allow MSOs to streamline the ability to bring new video, voice and data services to market quickly. CCAP can generate all QAMs used in the cable network, and any QAM can be used for either broadcast, narrowcast MPEG-TS video or DOCSIS. The use of each QAM within each service group is simply configured via the operational support system interface. A QAM can be changed from broadcast video to narrowcast video to DOCSIS – literally instantly – via a change in the CCAP configuration.

Operational readiness trial
Is the deployment and operation of CCAP equipment the same as that of a CMTS and/or an edge QAM with more QAMs?

The best way to know is to conduct an operational readiness trial (ORT). And the early findings from the ORT being conducted by Comcast show that the migration from current equipment to CCAP will involve operational changes. Some changes were known, but others are being found during the trial.

The concept is to have an ORT of a CCAP-like network to better understand the technical/operational issues and prepare accordingly. Given that CCAP equipment is not yet available, the idea is to emulate how a CCAP would operate in the network, mostly looking at the DS where things are changing. The focus is not on evaluating the equipment itself, but to establish the operational and network readiness for deploying CCAP devices.

The objective of the ORT is to understand the impact in the following areas:

  • Operational processes – monitoring, management, troubleshooting.
  • Tools – configuration, monitoring, capacity management, etc.
  • Network engineering requirements and options.

The scope would be small but meaningful. The ORT targets four high-speed Internet and three VOD service groups across eight nodes. Of course, extensive testing will take place before the small-scale deployment trial starts, which will include lab testing (Comcast CCAP pre-certification), headend internal technical testing and, finally, migrating trial participants.

The trial will be conducted in two phases:

  • Phase 1: Isolated test network environment to evaluate equipment.
  • Phase 2: Roll out to actual subscribers in production network.

Trial success is defined as: a CCAP-like network operating with real subscribers, carrying converged services for weeks and achieving a majority of the defined tasks.

ORT lessons
While the ORT is not completed yet, it has been underway for several months, and the results already show that some operational changes will be needed to deploy and operate CCAP devices.

Network operations
It will be necessary to get the network operations organization and processes ready to support CCAP devices. To that end, the CCAP ORT is keenly focused on ensuring that engineering and operations teams for the various services, which have traditionally worked independently given the different equipment they have managed, operate together and coordinate activities around CCAP's unified platform.

Today, many services are delivered through devices isolated by the services they deliver. Most MSOs separately configure and manage services, including linear video, VOD, voice and data. Services are segmented from a network infrastructure perspective, and they leverage different tools for each service.

With CCAP, one of the biggest challenges will be to more closely coordinate configuration, maintenance, troubleshooting and upgrade activities so as not to impact other services provisioned on the platform. Traps and alarms will also need to be correlated across the platform since the CCAP will have the ability to create alarms for multiple services, which could be destined for a variety of support tools and groups within the operator’s environment. Controlling access and privilege levels within the CCAP will be crucial to the management of services since multiple groups could be working on the platform at the same time. This could prompt a review of the roles and responsibilities of many of the support organizations that will manage the platform.

Combining the services within a CCAP box opens up the dilemma of which of the current service organizations will manage the CCAP management traffic. There will be one “reset button” in the end, and its use will have to be coordinated.

Operational support systems
The trial also takes a deep dive into backend systems, including how CCAP services will be configured, monitored and managed. Due to the number of services planned to be configured on a single CCAP platform, service configuration processes will need to be implemented, which will aid in the initial configuration, in any periodic changes in configuration to support changes as required and in realignment of services as new narrowcast services are expanded.

There are many systems that will need to be adapted, such as creating XML interfaces for configuration, modifying SNMP interfaces for monitoring, changing alarm receivers and adapting trouble ticket systems, to name a few. Additional tools for augmentation will be required, and existing tools will need to be modified.

Acquisition, deployment and growth
When CCAPs become available depends upon vendors’ equipment readiness, but some gear should be ready in time to start modest deployments in 2012, and much more through 2013. Deployment of CCAPs will likely follow a cap-and-grow approach, with purchases migrating to CCAPs while current equipment is relocated, as has been done with many other evolving technologies in the past.

This brings us to yet another aspect that changes with CCAP. Who will buy CCAPs, who will pay for CCAPs and who will deploy CCAPs will be yet another set of operational decisions moving forward.

In the past, if DOCSIS QAMs were needed, those would usually be purchased from the HSD growth budget. And if VOD QAMs were needed, those would be purchased from the video growth budget. And, likely, different groups within an MSO would carry out those purchases and the subsequent deployments.

Moving forward, when a CCAP is purchased and deployed, one group within the MSO will have to carry out the tasks. And when capacity augments require it, service group segmentations will require the addition of a CCAP port for all services. So these tasks will likely result in organizational and budgeting process changes.

Planning ahead
For all of the above reasons, MSOs planning to take advantage of the CCAP benefits as soon as the equipment becomes available might choose to address the operational changes that could be required as soon as practical. We hope that this summary helps identify the specific areas where coordination of activities and/or procedural changes could be required.

Emails: jorge_salinger@cable.comcast.com | ty_pearman@cable.comcast.com

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