Small cells are a boon for mobile network operators, as they easily and cheaply expand wireless network connectivity. However, they also can strain an operator’s evolved packet core (EPC).
“The EPC may be called upon to deliver a significant increase in scale, capacity, and performance beyond that which was required initially to support the macro-cellular network,” noted David Nowoswiat, Sr. Product and Solutions Marketing Manager, Alcatel-Lucent in a recent TechZine posting, Is your EPC ready for the small cells onslaught? He suggests that operators look at three areas when examining if their EPC is up for the challenge.
First, is the network architecture ready for numerous small cells. Two of the options involve the addition of a small cell gateway to aggregate control and/or user traffic from a group of small cells back to the EPC, while a third option brings direct connectivity from each small cell to the EPC.
Adding a small cell gateway reduces the scaling and capacity requirements of the EPC but increases the network and operations complexity, and connecting the EPC directly to each small cell significantly increases its scalability and performance requirements yet keeps the network flat. Each operator will need to assess what makes sense in their particular case.
Second, does the EPC support the scaling and performance of the additional small cells load.
“If it’s directly connected to the small cell network, the biggest impact is on the control plane and the mobility management entity (MME) -- with all of the additional signaling that’s required,” noted Nowoswiat. But the EPC also should support an integrated and operationally simple model.
Third, is the mobile operator to offload data to take some of the load off of the EPC. Local breakout options can be implemented in small cell networks to offload data traffic that brings little value to the mobile operator, thus saving the EPC from added load. In that case, though, the EPC must support the requirements necessary to redirect traffic to the appropriate gateway and packet data network.
Nowoswiat questions whether most EPCs are up to the challenge. Is a virtual EPC a better option and a way to handle the extra load from small cells? While the answer is “it depends,” to learn more about EPC and small cell network choices the whitepaper Evolved Packet Core for Small Cell Networks, which compares architecture options, is a great place to start.
Carriers’ mobile networks are extremely vulnerable to sudden changes in the signaling behavior of popular applications. In fact, Patrick McCabe, Senior Product Marketing Manager, Alcatel-Lucent, devolves into this subject in some detail in a recent blog, Google’s power to impact network signaling. In fact, while Google Cloud Messages provide an example in the blog, the companies recent Mobile Device Report goes into the topic regarding the impact of the top mobile apps on signaling in greater detail.
Google Cloud Messaging for Android, according to the search giant, is a service that allows data to be sent from the App Engine or other backends to users’ Android-powered devices. That could involve the transmission of a lightweight push notification telling an Android application that there is new data to be accessed from the server (like a movie uploaded by a friend) or a message containing up to 4kb of payload data (so apps like IM can consume the message directly).
Such apps and interactions, however, can have a notable and negative impact on both mobile networks and the endpoints connected to them, according to McCabe. And, in the case of Google Cloud Messaging for Android there is ample evidence it already has.
The study by Alcatel-Lucent indicated there was a dramatic increase in signaling traffic from Jan. 12 to Feb. 19 due to the Google Cloud Messaging application. That involved a Jan. 12 signaling increase from 17 percent to 20 percent. Then, on Feb. 4, such signaling went from 21 percent to a peak 23 percent. Signaling relative to this Google application returned to expected levels on Feb. 19, according to Alcatel-Lucent, which added that these variations were not due to any increases in active subscribers.
The reason why Alcatel-Lucent is highlighting this is to increase awareness of the challenges for the signaling network and the mobile network at large, as well as a drain on related user endpoints (in this case Android smartphones) that the explosion in applications is causing.
“Although a rise in signaling share from 17 percent to 23 percent on a single application may appear rather innocuous at first, it does have a significant impact on mobile networks,” writes McCabe, based on information derived from Alcatel-Lucent’s the Motive Wireless Network Guardian for mobile network analysis. “During this period of signaling increase, an average erosion of 6 percent in overall signaling capacity was experienced across the networks that were analyzed. This is a costly loss that can place a large strain on radio resources, and it can even cause outages in locations that were already operating close to capacity — or where there was a dominant proportion of Android users.”
Concentration of the impact of the increasingly app-centric use of the network tends to look almost exclusively at traffic in general. However, in order for all of those apps to work with a high quality of service (QoS) the signaling network needs to be able to understand accommodate the spikes the various types of apps can cause. It is why having network visibility into app impact on signaling is so important.
]]>As they move into the cloud era, network operators need a service aware network operations tool to assure virtual network functions (VNF) management. They’ll need it to efficiently perform a variety of network operations tasks, including:
As described in a vEPC post related to converging NMS and VNF manager functions within the ETSI Management and Orchestration (MANO) architecture, operators need to evolve their network operations tools for NFV through tighter coupling the NMS and VNF manager functions. Specifically for VNF assurance, the blog states “Troubleshooting is simplified because traditional NMS faults/events are correlated with VNF related events/faults. The VNFM provides lifecycle management and automates the self-healing of VNFs.”
In addition to the ETSI MANO architecture, progress has been made in the ETSI specification for defining NFV Service Quality Metrics that strives to enable better engineering of VNF user service quality, more efficient fault localization and mitigation, and faster identification of true root cause of service impairment so proper corrective actions can be taken promptly.
As NFV service quality metrics and traditional network service performance are continuously monitored, a service aware infrastructure relationship model within a network operations tool will be important for it to be able to innately correlate events to the true root-cause of service impacting problems, without having to develop and pre-configure volumes of custom handling policy rules and scripts. In addition, this model will allow operators to perform a more rapid service impact assessment for network events under investigation, as well as speed fault isolation and resolution.
And to make this more advanced fault management meaningful for network operators, assurance visualization will help by providing intuitive views for easily understanding how a multitude of events and key quality indicators (KQIs) relate to each other, with clear visibility into the root-cause of problems. It will also insightfully give operators an understanding of the time-line for events and state changes in the network to give a better indication of cause and possible effects.
This blog is the 2nd in a series that discusses the evolution of network and service assurance. The 1st blog gives a general overview on how network operations tools can be more efficient.
ASSURING THE EVER-CHANGING STATE OF THE VIRTUAL NETWORK
VNF configurations will be far more dynamic than with physical network elements (PNF), presenting new challenges for network operations tools to keep pace with many events related to highly dynamic network state changes and elastic scaling.
Manual processes that piece together assurance data from disparate views will not be sufficient to keep pace in this highly dynamic NFV environment. And traditional real-time-only monitoring and assurance views will not be effective when a VNF could be here in 1 moment and scaled down and gone in the next. This means that there is a need for both current and historical events and state information to be intelligently processed with near real-time performance, and at large scale.
Consider how much more meaningful it would be for network operators if assurance views could be made more intuitive for easily understanding how all the network events and MANO related KQIs relate to each other. For example, wouldn’t it be more insightful for operators troubleshooting a service performance issue to have a timeline that shows the service impacting threshold crossing alerts (TCAs) as well as whether orchestration or network events occurred in the same general timeframe?
ENHANCING NFV ASSURANCE WITH SERVICE QUALITY METRICS
As VNF deployments increase, network operations tools will need to evolve with new NFV service quality metric definitions and provide intelligence for correlating the multitude of different events coming from the various types of NFV infrastructure and MANO elements. Specifically related to troubleshooting and root-cause analysis that works in coordination with VNF lifecycle management, operators need service aware visibility and traceability to the various possible service quality impacting layers.
For operations to be effective in a highly dynamic environment with network services that depend on both VNFs and PNFs for underlying network infrastructure, there must be a service aware understanding of the relationships between services and these VNFs and PNFs. And equally important, there also must be a mapping of how service quality events triggered by virtual machines, VNFs, and orchestration layers impact or trigger changes in dependent layers.
For example, when there are issues with virtual network provisioning latency or reliability or diversity compliance, these conditions may trigger actions within the orchestration layer. But as a primary concern of network operators:
Without a network operation tool that can provide this type of intelligence for assuring VNFs, operators will not have the visibility needed to understand whether a problem is within the scope of their control. And this is the type of information would not only be highly valuable for troubleshooting, but even more broadly for clarifying accountability for a localized problem across various organization groups from IT to the different network domain groups.
Operators require a unified network operations tool that has evolved with the intelligence to meet all of these new NFV related assurance challenges. This tool must possess a service aware model that is unified with NFV lifecycle management. It must scale and perform to keep pace with tracking huge volumes of events that reflect the continual state of flux of change across service quality impacting layers. (For more examples of service quality metrics that provide requirements for assuring virtual networks, please refer to the ETSI specification for defining NFV Service Quality Metrics.)
EVOLVING ASSURANCE WITH ADVANCED FAULT MANAGEMENT
Operators deploying NFV require advanced fault management that provides both current and historical visibility for root-cause analysis, so that active faults can be correlated with past ones as the state of the network changes. This historical fault correlation is essential for pinpointing the root cause of problems in the highly dynamic virtualized network where MANO triggered corrective actions could potentially make intermittently reoccurring customer impacting issues difficult to investigate.
And network and service assurance tools in the cloud /NFV era must scale to track the full history of related service impacting events so network operators can perform both real-time troubleshooting and trend analysis.
Tools also need to have the intelligence to detect reoccurring problems. Specifically, operators require a tool that can help them to assess whether corrective resolutions that were automated are successful, or whether they are failing. And if failing, whether the failures are persistent or intermittent, and whether there is an actionable probable cause against the network infrastructure within the scope of the network operator’s control. And amongst the high volumes of events, there will also be a need to suppress (or filter out) events that do not require an action by the network operations team.
The following video demo offers a deeper dive into an advanced fault management application from Alcatel-Lucent.
RELATED MATERIALS
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From original TechZine article
Can the virtualized evolved packet core (vEPC) be deployed today in large scale, LTE networks? Mobile network operators (MNOs) are increasingly convinced that the vEPC has become viable both financially and technically. And I think so, too, based upon the advances made over the past year that I’ll discuss in this blog.
Advancements in vEPC scaling and performance
Early in 2014, the vEPC proofs of concept and field trials of virtualized mobility management and gateway products were limited in both scale and performance. But as the year progressed, advancements in the design and architecture used network functions virtualization (NFV) tools and capabilities that greatly improved their capacity and performance.
These improvements, together with other software enhancements, such as the Data Plane Development Kit (DPDK), have the vSGW/vPGW approaching the capacity and performance of dedicated hardware platforms.
Converged NMS/VNF manager: The key to seamless vEPC network operations
A lot of progress has been made with enhancements to the ETSI Management and Orchestration (MANO) architecture. However, rather than having separate element management system (EMS) and VNF manager (VNFM) functions, there’s been a move to converge these functions since both are integral to managing the VNFs. (The EMS described by MANO includes both network and element management (NMS/EMS) functions).
By unifying the VNF manager and NMS functions, an MNO can seamlessly manage and orchestrate the vEPC. This makes it easy for an MNO to perform VNF lifecycle management functions from the same NMS that is used on a day-to-day basis for network operations.
When EMS and VNFM are converged:
The traditional NMS Fault, Configuration, Accounting, Performance and Security (FCAPS) management function is now applicable to both the EPC VNFs and the physical network functions (PNF). This enables a common and consistent approach.
This also provides the topology and logical connectivity of the individual VNFs/PNFs and more advanced performance and SLA reporting. A single manager simplifies overall coordination and adaptation for configuration and event reporting between the virtualized infrastructure manager (VIM) and the NMS.
Troubleshooting is simplified because traditional NMS faults/events are correlated with VNF related events/faults. The VNFM provides lifecycle management and automates the self-healing of VNFs. It uses recipes to describe the vEPC VNF, its VNF components (underlying VM instances) and their interdependencies. Each VNF component has its own recipe, which includes a description of how to monitor, self-heal, and scale it.
With coordinated fault management and automated self-healing, the MNO’s operations team will have the visibility and intelligence to understand whether alarms are caused by normal maintenance activities or are indeed an emerging issue that they need to react to quickly. In addition, new advanced NMS approaches to network assurance visualization will speed problem assessment for both VNF and PNFs. These developments will also provide the VNF and network event data to support reporting and analysis.
When the VNFM and the NMS are combined into a single management functional instance, the management and orchestration of the vEPC VNF and integration of the vEPC into the existing OSS/BSS infrastructure is greatly simplified. This is because the VNFM/ NMS has complete knowledge and visibility of VNFs within the physical and virtual EPC network.
Is the vEPC ready for commercial deployment?
Based on the progress made in both the scalability and performance of the vEPC VNFs and the advances made in management and orchestration of the vEPC, 2015 will be the year for vEPC deployments to commence at some Tier 1 mobile operators. The momentum and confidence of mobile operators in NFV will make it a reality.
Alcatel-Lucent at Mobile World Congress
Alcatel-Lucent will have a large presence at Mobile World Congress in Barcelona. I will take part in a panel discussion on “Unifying Network IT and Telco IT” on Thursday, March 5th from 11.30 – 13.00.
We will also be demonstrating our vEPC at our booth. There you will be able to see the dynamic scaling of our Virtualized Mobile Gateway and the operational elegance of our NMS/VNFM system. I look forward to seeing you there and discussing how our vEPC solution can meet your NFV evolution plans.
Related Material
To contact the author or request additional information, please send an email to techzine.editor@alcatel-lucent.com.
]]>By: Kevin Landry, Product Marketing Manager, Alcatel-Lucent
From original TechZine article
Assurance visualization can prepare network operations tools to meet the demands of increasingly complex networks. And the limitations of today’s tools are indeed a cause for concern.
As networks evolve to next-generation IP/optical technologies, cloud networking, software defined networking (SDN), and network functions virtualization (NFV), network operations tools need to evolve, too.
The Network Operations Tools Evolution
Innovation is happening and better technologies are emerging. Among them, network assurance visualization is useful for enhancing network monitoring, troubleshooting, and analytics.
NFV and SDN require network management systems (NMS) to meet the new performance monitoring and assurance visualization challenges created by these rapidly changing virtualized network environments. And big data analytics and new web software frameworks have unlocked the potential for new assurance visualization approaches that will radically change network operations tools.
The end result will be a dramatically enhanced, more visually insightful approach for assuring networks and services that enable operators to utilize a wealth of real-time and historical data in a meaningful and effective way.
This blog is the first in a series that discusses network assurance visualization in the context of gaining efficiency in addressing various network operations challenges.
Traditional Fault Management Can Impede Efficiency
Even the most seasoned network operators find it challenging to diagnose the problems in a network with high fault volumes. To manually interpret alarms within an alarm list and isolate problems efficiently, you need to identify the relatively smaller number of root causes quickly and focus on investigating the highest priority problems first.
Some of the better fault management and network operations tools in the industry simplify and automate this process through alarm de-duplication, suppression, and correlation. This de-clutters the alarm list by lowering the number of alarms that network and service operators have to filter and sort through.
“Service aware” network operations tools go further by performing alarm correlation between services and underlying infrastructure, out-of-the-box. There’s no need to develop custom configurations or scripts to map out the many relationships needed to link the volumes of individual services to all the underlying network infrastructure layers and network resources. Service aware network operations tools are also able to correlate alarms network-wide across end-to-end services composed of multiple service segments – even if they use different service types or span different network technology domains.
Despite some of the latest network operations software technology advancements, operators can still find it difficult to know where to start when there are many active faults – especially when using the more traditional fault management approach that involves navigating alarm lists. It is also not uncommon for operators to sometimes lose their bearings as they open many windows when troubleshooting faults across multiple different views and forms.
It is often difficult and time-consuming to uncover and prioritize all the root problems from symptomatic alarms. This can mean that operators only address the root cause of problems on a best-effort basis. Alarms unrelated to the particular fault being investigated may tend to move operators in the wrong direction when troubleshooting a specific problem – and this increases the mean time to resolution (MTTR).
Service Aware Fault Management with Assurance Visualization
Many traditional network operations challenges can be alleviated by adding assurance visualization to fault management workflows within a service aware NMS.
For the most effective assurance visualization, it is fundamental to use service aware network operations tools that possess a high performing, scalable framework for alarm and event correlation. This will insure a highly optimized environment for efficient traversal of relationships across the managed network and services model in-memory. And that’s exactly the prerequisite to be able to pinpoint root causes with speed and at scale, while also enabling their isolation from downstream network infrastructure impacts.
With this advanced service aware fault management, issues are automatically isolated down to the root cause to enable the delivery of assurance visualization. Assurance visualization enables network operations to detect emerging problems faster and accelerate the troubleshooting process to reduce MTTR. It achieves this by giving network operators intuitive, holistic views so they can:
RELATED MATERIALS
To contact the author or request additional information, please send an email to techzine.editor@alcatel-lucent.com.
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