For example, if you. Scalability describes a system’s elasticity. They are as impactful to cloud computing as bookkeeping is to financial reports. Scalability and elasticity are fundamental elements of cloud computing. Start optimizing your cloud infrastructure today! Cost Effectiveness. This could include growing the capacity of a cloud-based system's central processing unit (CPU), for instance, or its storage resources or memory. Scalability and elasticity represent a system that can grow in both capacity and resources, making them somewhat similar. An essential. Scaling out vs. What is the difference between elasticity and scalability in cloud computing. Elastic environments care about being able to meet current demands without under/over provisioning, in an autonomic fashion. Types of Cloud Scalability: Manual vs. 1: horizon- tal and vertical. While the two terms are often used interchangeably, they have distinct differences. Elasticity: A cloud's elasticity refers to its ability to adapt to shifts in demand by scaling resources up or down to provide additional resources during increased workloads and release them when not needed. 4 min read - Organizations worldwide are embracing the power of cloud computing to drive innovation, enhance scalability and improve operational efficiency. If a cloud resource is scalable, then it enables stable system growth without impacting performance. It refers to a system's capacity to handle heavier or lighter loads. Cloud Concepts. fokusfocus • 3 yr. The key difference is, scalable systems don't necessarily mean they will scale up/down - it's only about being able to reach. Elasticity takes it a step further emphasizing the dynamic allocation and deallocation of resources based on. Zilliz is 102x and 65x more cost-effective than Elastic Cloud when processing 1 million vectors with 768 dimensions. vertical scaling Horizontal scaling and vertical scaling are two different approaches used for increasing the performance and capacity of a system. We would like to show you a description here but the site won’t allow us. It requires an engineer to manage scaling up and out or down. Cloud providers can offer both elastic and scalable solutions. ELASTICITY Elasticity Elasticity of Composites Viscoelasticity Elasticity of Crystals (Elastic Anisotropy) Elasticity: Theory, Applications and 5G Network Evolution with AWS€¦ · For the Core Network aspect, 3GPP 1 defines 5G. ”We all know how we scale a highway system—we add more traffic lanes so it can handle a greater number of vehicles. There is often a misconception between Scalability and Elasticity. An elastic system can be used to detect any changes in the workflows and also processes in the cloud. scalability lies in their functions: Cloud Elasticity is a tactical resource allocation operation. At its most basic level, database scalability can be divided into two types: Vertical scaling, or scaling up or down, where you increase or decrease computing power or databases as needed—either by changing performance levels or by using elastic database pools to automatically adjust to your workload demands. What’s the difference? Cloud scalability is not to be confused with cloud elasticity. Elasticity is the ability to fit the resources. vertical scaling Horizontal scaling and vertical scaling are two different approaches used for increasing the performance and capacity of a system. Because these two terms. On-Premise Vs. Cloud elasticity and cloud scalability may sound like synonyms, but from a cloud service standpoint, they mean two different things. The key motivations for people to utilize cloud services are elasticity and scalability [10]. Scalability requires manual intervention, while elasticity is completely automated. Cloud Elasticity While both scalability and elasticity are critical in cloud computing , they serve different purposes. Scaling vertically. Next. external usage – number of customers visiting the websiteBest Practices for Information Architecture Planning. ContentMost asked in [amazon web services]ScalabilityWhat is Cloud Scalability?What is cloud elasticity?What Is Elasticity In Cloud Computing?Infosys Partners With Microsoft to Bolster Global Cloud Adoption Users of an application require network connectivity to the computers that run the applicatio…Vertical Scaling Advantages. For example, we have two types of scaling: HORIZONTAL SCALING (known as Elastic model): Increase memory and storage (etc. It is the ability to fit the computing resources requisite to cope up with workload dynamically with respect to scale out. Load Testing. Let’s talk about the three most important features of scalability in cloud platforms. Elasticity vs Scalability We frequently hear about the concepts of "elasticity" and "scalability" in cloud computing in tandem with each other. Cloud Scalability vs Cloud Elasticity. While elasticity usually involves the dynamic allocation of. While the two concepts sound like the same thing, the key difference between cloud scalability and cloud elasticity is time. Scalable environments only care about increasing capacity to accommodate an increasing workload. ; Upgrading specific components costs less than purchasing a new server. menu. The most expensive AWS instance, with 3. Scalability and elasticity—the ability to add capacity. the ability of a system to adapt to a changing. It is of two types - horizontal and vertical. • High Availability vs Scalability (vertical and horizontal) vs Elasticity vs Agility in the Cloud • Elastic Load Balancers (ELB) • Distribute traffic across backend EC2 instances, which can be Multi-AZ • Supports health checks • 3 types: Application LB (HTTP – L7), Network LB (TCP – L4), Classic LB (old)Содержание Scalability Vs Elasticity: A Comparative Analysis Azure High Elasticity Design For Scalability Vertical Scaling Scale Cloud Resources To Meet Your Example Of Cloud Scalability What Is The Difference Between Elasticity And Scalability? This means they only need to scale the patient portal, not the physician or office portals. Scalable and elastic solutions are both available from cloud providers. Scalability and elasticity are related, though they are different aspects of database availability. Elasticity allows your system to adjust the number and size of components and services based on workload and performance metrics, while autoscaling lets it automatically scale up or down based on. Cloud elasticity vs. The system starts on a particular scale, and its resources and needs require room for gradual improvement as it is being used. To avoid these issues, more lanes are added, and an overpass is constructed. Cloud Security - I ain’t rocket science @ Club. Elasticity in the cloud allows you to adapt to your workload needs quickly. 93 Scalability is the ability of the system to accommodate larger loads just by adding resources either making hardware stronger (scale up) or adding additional nodes (scale out). private cloud Private cloud is cloud infrastructure operated exclusively for one company. Elasticity is a dynamic property for cloud computing. Elasticity. Indeed, utilizing intelligent automation can transform how an organization leverages its. Performance is validated by testing the scalability and the reliability of hardware, software and network. This means. Elasticity. In essence, when demand spikes, additional instances are spawned; conversely, when demand plummets, superfluous instances are terminated seamlessly. Elasticity. Scalability is that feature which allows your system to adjust resources with change in load or demand. In AWS, the process of getting the resources dynamically when you actually require them and then release the resources when you are done and do not need them is known as elasticity. Cloud scalability, on the other hand, is for long-term growth that is strategically planned. Fast response times as there are no synchronized nodes that communicate with each other. At work, three excellent examples of cloud elasticity include e-commerce, insurance, and streaming services. 4. Scalability vs Elasticity. scaling up. A discussion of scalability wouldn’t be complete without mentioning elasticity—a similar metric but one with a slightly different meaning. The recorded information includes the. Scalability and elasticity represent a system that can grow in both capacity and resources, making them somewhat similar. This is 'cloud-friendly': pay per use, match demand, optimized costsCloud providers have LOTS of resources available and generally (sometimes there are resources shortages) you can increase what you need without worrying you are going to bring down the rest of your systems. Test elasticity both up and down, ensuring it will meet requirements for load variance. Customers can simplify application deployment, management, and scalability while improving uptime with the recently introduced flexible orchestration mode. Elasticity refers to the capability of a cloud to automatically boost or shorten the infrastructural resources, depending on the requirement so that the workload can be. What is elastic computing or cloud elasticity? Elastic computing is the ability to quickly expand or decrease computer processing, memory, and storage resources to meet changing demands without worrying about capacity planning and engineering for peak usage. ) without it negatively affecting performance. Meanwhile,. The key to cloud adaptability is the capacity to increase or decrease IT resources according to demand shifts. Cloud computing. Cloud Elasticity can be triggered and executed automatically based on workload. Cloud elasticity enables businesses to swiftly spawn computing resources in no time. EC2 Image Builder. Even when using a single cloud provider, Vance recommends running in different regions, so that if one fails, another is there to back. By Jim Cheshire. e. Session data should be moved off the EC2 instances. Because these two terms. Although they sound similar, cloud scalability and elasticity are not the same things. Most people, when thinking of cloud computing, think of the ease with which they can procure resources when needed. In this sample chapter from Exam Ref AZ-900 Microsoft Azure Fundamentals, author Jim Cheshire covers the benefits of using the cloud, the different cloud services that are available, and cloud models that enable a variety of cloud configurations. There are 9 main types of scalability in cloud computing: 1. 5. Although these two phrases are frequently used synonymously, they are distinct from one another. Cloud Scaling; Cost: The Grand Determinant; What Is Scalability? Scalability describes a system’s elasticity. Picture a restaurant in an excellent. You won’t overpay for off-peak periods. Application. September 13, 2023. 16, we focused on scale, pushing the limits of Elasticsearch to make search even faster, memory less demanding, and clusters more stable. ) without it negatively affecting performance. Cloud computing solutions can do just that, which is why the market has. This is different from scalability, or, if you. While scalability helps handle long-term growth, elasticity ensures flawless service availability at present. Both scalability and elasticity are related to the number of requests that can be made concurrently in a cloud system — they are not mutually exclusive; both. It provides the necessary resources and capacity required for the current. Cloud scalability and cloud elasticity allow you to efficiently manage resources. Submit Search. The key to cloud adaptability is the capacity to increase or decrease IT resources according to demand shifts. Scalability means to increase from 5 to 50 instances. Now that we have an understanding of elasticity and scaling from the AZ-900 Series Part 2: Scalability and Elasticity post, let’s talk about another benefit which cloud computing provides – high availability. The terms scalability, high availability, performance, and mission-critical can mean different things to different organizations, or to different. Availability of cloud storage and its scalability features is a key component of storage resources planning. Elasticity. The key difference between scalability and elasticity is the level of automation. If every 1,000 users you get, you need 2x the amount of servers, then it can be said your design does not scale, as you would quickly run out of money as your user count grew. Cloud providers can offer both elastic and scalable solutions. Scalability and Elasticity both are essential characteristics of cloud computing & Now, it is clear that the ability of a system to scale down or scale up is fundamental, but it is entirely different from its capability to respond quickly. It majorly affects RAM, bandwidth, and storage as the workload changes. Cloud Concepts. Here are few basic points. Cloud elasticity is required for short-term bursts, such as a spike in website traffic as a result of a sales promotion. An elastic cloud service increases or decreases the available resources dynamically to match an organization’s needs. On the other hand, scalability tackles an application’s varying. I read from the book of T. Over-provisioning is when more resources are allocated than are required, and it should be avoided, particularly in a cloud model because the service provider must pay for all allocated resources, which can increase the cost. 89 TB of RAM and 128 CPUs. Customers can also gain greater. One of the most important considerations when migrating to cloud computing may be cloud. . 8:17 pm. private cloud Private cloud is cloud infrastructure operated exclusively for one company. Related Readings:Powered by Higher Logic. There are two kinds of scaling: horizontal and vertical. Let's look deeper into these terms. Cloud Elasticity vs Scalability. Scalability is used to meet the static increase in the workload. If we ask Wikipedia for a definition, it tells us, “Scalability is the property of a system to handle a growing amount of work by adding resources to the system. A successful WordPress website must host itself elastically on multiple servers, to avoid the pitfalls of single server hosting and vertical scaling. It refers to a system's capacity to handle heavier or lighter loads. With scalability in the cloud you can move in lots of directions, so you can scale up or scale out. While the magnitude of these aspects is extremely important when it comes to cloud infrastructure, there are a few other areas that have. Cloud Elasticity. this. Microsoft Azure Elastic Storage provides high availability, scale-out capacity, data protection and redundancy for data. Indeed the notion of elastic resources in the IT supply chain is so desirable that Amazon named their cloud platform. While. Microsoft Azure Elastic Storage provides high availability, scale-out capacity, data protection and redundancy for data. Cloud Scalability vs Cloud Elasticity: Here’s How They Differ It adds (but doesn’t subtract) its static amount of resources, based on however much is demanded of it. Scalability refers to the growing or shrinking of workflows or architectures in pre-built infrastructures without impacting performance. e. calability V/S Elasticity - Overview | A Comprehensive Guide | Cloud Interview Questions | #AWS #Azure #GCPLink to the Blog: means the system can bring on other resources (ie add databases, cpus, caches) or deactivate them based on traffic demand. 6/21/2019. You can match the number of resources allocated with the number of resources required at any given time, thanks to cloud elasticity. Cloud Elasticity. Most cloud providers solve the problem of having to choose between the two, as any cloud is capable of having elasticity and scalability. While the two concepts sound like the same thing, the key difference between cloud scalability and cloud elasticity is time. Typically, a private cloud is hosted on-premises, behind the client company’s own firewall, but it can also be hosted on dedicated cloud provider or third-party infrastructure. {"matched_rule":{"source":"/blog(([/\\?]. Although they’re often mentioned in the same breath and even used synonymously, cloud elasticity and cloud scalability aren’t quite the same thing. Types of Scalability in Cloud Computing. Horizontal scaling vs. Learn more about the differences between cloud scalability and cloud elasticity, the benefits of the […] Cloud Scalability vs. While scalability frequently entails the delivery of new servers to accommodate static demand growth, elasticity typically entails the dynamic allocation of CPU and memory resources. Elastic environments care about being able to meet current demands without under/over provisioning, in an autonomic fashion. Scalability handles the increase and decrease of resources according to the system's workload. Cloud scalability, on the other hand, enables you to add or remove resources within existing infrastructure to meet the changing needs of an application. At its most basic level, database scalability can be divided into two types: Vertical scaling, or scaling up or down, where you increase or decrease computing power or databases as needed—either by changing performance levels or by using elastic database pools to automatically adjust to your workload demands. Differentiate between elasticity and Scalability and how they are ensured in Cloud computing ecosystem. Cloud solutions architects should ideally “build today with tomorrow in mind,” meaning their solutions need to cater to current scale requirements as well as the anticipated growth of. Scalability vs Elasticity: Many people confuse these 2 terms as one and the same thing, when they are discussed in the context of cloud computing, though they are not. Scalability can either be vertical (scale-up with in a system) or horizontal (scale-out multiple systems in most cases but not always linearly). Understand cloud concepts. Cloud scalability and cloud elasticity allow you to efficiently manage resources. I interprete elasticity as the capability to react to more or less daily variation in resource needs. Elasticity refers to a system’s ability to grow or shrink dynamically in response to changing workload demands, like a sudden spike in web traffic. Conclusion of Cloud Elasticity in Cloud Scalability. Azure Elastic SAN is a cloud-native service that offers a scalable, cost-effective, high-performance, and comprehensive storage solution for a range of compute options. When reading about cloud scalability, you have probably come across the term “cloud elasticity. Elastic workloads, however,. One of the most common and effective ways to measure the scalability of your cloud application is to perform load testing. Elastic environments care about being able to meet current demands without under/over provisioning, in an autonomic fashion. As the most popular model of cloud computing services, the public cloud offers vast choices in terms of solutions and computing resources to address the growing needs of organizations of all sizes and verticals. If you are looking for Rapid Elasticity In Cloud Computing – digitalpictures you’ve came to the right web. Scalability: Adjusting capacity to meet demand. Public clouds offer services at low costs and in turn offer a product that can be utilized by a wide audience. The ability to acquire resources as you need them and release resources when you no longer need them. Cloud load balancing is defined as the method of splitting workloads and computing properties in a cloud computing. the ability of a system to adapt to a changing. i. The term “elasticity” describes a system’s capacity to expand or contract dynamically in response to shifting workload needs, such as an unexpected increase in web traffic. Cloud scalability, on the other hand, is for long-term growth that is strategically planned. Elasticity is the ability of your IT system to automatically adjust the resources allocated to it based on the current demand. The real difference lies in the requirements and conditions under which they function. It provides an overview of services, including: Ideal usage patterns. For example, if you have a sudden spike in your web. Elasticity is the capability for a cloud-based program to require more or fewer resources, to put it simply. Horizontal and Vertical Cloud Scaling Similarities. Scalability. Learn how azure elasticity and scalability Concepts works, this lecture is part of the Azure AZ-900 Exam. Cloud elasticity. How they work together and the difference between the two. In this sample chapter from Exam Ref AZ-900 Microsoft Azure Fundamentals, author Jim Cheshire covers the benefits of using the cloud, the different cloud services that are available, and cloud models that enable a variety of cloud configurations. Auto-Scalability and elasticity both refers to an "automated jobs", so I think the correct answer is here "elasticity". Published: 20 Sep 2022. Ensure scalability and flexibility for future growth. It’s the more cost-saving choice and it’s useful for tasks and environments where the workload is stable and has a predictable capacity and growth planning. Step 3 – Click on the ADD button to add a new triggers. But cloud elasticity and cloud scalability are still considered equal. 97/hour. Elastic computing plays a pivotal role in managing the cloud servers in cloud computing. Page 1 of 2. Although these two phrases are frequently used synonymously, they are distinct from one another. Scalability manages an application's shifting requirements within the constraints of the infrastructure by statically adding or removing resources as necessary to fulfill application demands. Elasticity therefore builds upon scalability and expands on it by adding the notion of automatic resource management. Scalability pertains to the amount of the number of machines you can throw at a problem, and having multiple machines to solve it. Demand includes . This adaptability enables organizations to deal with a variety of situations. Elasticity is used to meet dynamic changes, where the resources need can increase or decrease. Difference Between Elasticity And Scalability In The Cloud. 4. Automatic Scaling. Many of the services in AWS are scalable by default, which is one of the reasons that AWS is so successful. GCP leads the pack with its largest instance, 3. Cloud elasticity vs. Cloud Scalability vs. #scalability #cloud #azurecloud scaling up offers elasticity. If you dabble with computing, you have likely read these words before. This refers to how well your cloud services are able to add and remove resources on demand. The easiest way to explain these two is that cloud scalability involves adding/deleting computing-resources within the existing cloud. Measured service. Scalability is the ability of a system to handle increasing or. Delivery of services like compute, storage and networking over the internet is known as Cloud Computing, and the provider of such services is known as Cloud Provider. Cloud Scalability Versus Cloud Elasticity. . Similar to cloud scalability, cloud elasticity refers to a system that can respond to workload demands in both directions, expanding and contracting like a rubber band. It allows you to scale up or scale out to meet the increasing workloads. It is a long-term event that is used to deal with an expected growth in demand. on December 13, 2022, 6:35 AM PST. Most people, when thinking of cloud computing, think of the ease with which they can procure resources when needed. 2: Elasticity is used to meet dynamic changes, where the resources need can increase or decrease. While these two terms sound identical, cloud scalability and elasticity are not the same. They are highly desired, after all! There are distinct differences between elasticity and scalability. An elastic system should immediately detect this condition and remove nine machines and release them to the cloud. A reliable service continues to respond to customer requests when there's a high demand on the service or when. There is often a misconception between Scalability and Elasticity. Cloud elasticity vs. Cloud Scalability vs. Cloud Scalability vs Cloud Elasticity. ” even though these terms are similar and are often used interchangeably, they have distinct differences. Scalability vs. Elasticity is related to the dynamic use of current resources, whereas scalability is the accommodation of larger workloads without the transformation of complete existing infrastructure. Elasticity is vital if you use a. Businesses are investing heavily in cloud computing resources, and professionals with the right set of skills are much in demand. enabling the hypervisor to create. Resource pooling. Erl (if I have understand it correctly) that scalability is the ability of a resource to increase or decrease by demand, and that elasticity is the automatic scaling of a resource by demand of a resource. In contrast, elasticity refers to daily/hourly capacity changes–when usage goes up and down. ” Well, cloud elasticity and cloud scalability are both fundamental elements of the cloud. High Availability. the “application level”), whereas “cloud elasticity” relates to infrastructure as a whole (i. While they are often used. Elasticity The purpose of Elasticity is to match the resources allocated. elasticity? Cloud scalability is the ability of a cloud computing system to handle increased workloads by adding more resources. For. Cloud elasticity combines with cloud scalability to ensure both customers and cloud platforms meet changing computing needs as and when required. Cloud provides you with solutions for improved scalability, efficiency, and productivity. So in cloud Virtual machine scale set you get automatic scale up and down of your VM instances. Here are some key similarities between horizontal and vertical cloud scaling. Elasticity. Agility refers to the ability to deploy new applications and services quickly. Scalability vs. For example, scalability enables you to go from one to a. It can be horizontal scaling, like adding more servers, or vertical scaling, like increasing a server's capacity. Multitenancy in Cloud computing: Multitenancy is a type of software architecture where a single software instance can serve multiple distinct user groups. Scalability is the ability of a system or network to handle increased load or usage. When it comes to cost management with elasticity vs scalability, elasticity optimizes more for off-peak times. There is a significant amount of confusion among buyers about storage scalability, elasticity and on-demand. Cloud Elasticity Cloud Scalability; 1: Elasticity is used just to meet the sudden up and down in the workload for a small period of time. Cloud computing introduces two essential concepts, scalability and elasticity, often used interchangeably but with distinct characteristics. Very soon, this two-lane highway is filled with cars, and accidents become common. When deciding which cloud service to use, it ultimately depends. . Overall, Cloud Scalability covers expected and predictable workload demands and handles rapid and unpredictable changes in operation scale. Cloud Elasticity Vs. Cloud scalability. Scalability, High Availability, and Performance. Essentially, the difference between the two is adding more cloud instances as opposed to making the instances larger. It is an ongoing process and not an end result. Содержание. There are two main types of scaling in cloud computing: vertical and horizontal. Cloud elasticity refers to the ability to quickly and temporarily adjust resources in response to sudden or seasonal changes in workload trends. Scalability is the measure of a system's ability to handle varying amounts of work by adding or removing resources from the system. Flexibility: change resource types when needed; Cost-Effectiveness: pay as you go, for what you use; Scalability: accommodate larger loads by making hardware stronger or adding additional nodes; Elasticity: ability to scale out and scale-in when needed; High-availability and fault-tolerance: build across data centersScalability vs. Scalability and elasticity in cloud: Scalability can be defined as the cloud's ability to manage workloads by increasing or decreasing resources per the demand. A company hosts everything in-house in an on-premise environment, while in a cloud environment, a third-party provider hosts all that for you. Cloud Elasticity can be automatic, without need to perform capacity planning in advance of the occasion, or it can be a manual process where the organization is notified they are running low on. Simply put, scalability is the ability to add or subtract computing resources as needed. Cloud Monitoring. Elasticity in Cloud Computing ☁️ Let's Simplify! 📈 Scalability: Often a manual process, it's about increasing capacity to handle growth - It can be: ** Vertical Scaling. The cloud gives you more options for building and deploying applications. Cloud elasticity vs. Elasticity pertains to individual machines and how much RAM and processing power it will need or use. “cloud scalability” is used in reference to shorter-term traffic demands. Elasticity The purpose of elasticity is to match the resources allocated with actual amount of resources needed at any. One of the most important considerations when migrating to cloud computing may be cloud. Elasticity vs. scale-out for storage, consider factors such as data growth expectations, budget, criticality of systems and existing hardware. scalability; elasticity; Laur155 155. Scalability vs Elasticity Scalability and elasticity are both important concepts in building a flexible and responsive system. ago. Scalability and Elasticity both refer to meeting traffic demand but in two different situations. Scalability. Elasticity is the degree to which a system can adapt to workload changes by provisioning and de-provisioning resources in an automated fashion [12]. Elasticity is best defined as a cloud computing service's ability to dynamically adapt to meet an organization's changing demands. Also, how elasticity is reliant on. Although many people tend to use these technical terms interchangeably, there are several contrasting differences between. Learn more about the differences between cloud scalability and cloud elasticity, the. Cloud Elasticity is a tactical resource allocation operation. JoaoPauloPereiraBarbosa-4539 5. This article will help shed some light on the difference between cloud elasticity and scalability in cloud computing and help you better choose which one is more useful to your needs. In fact, Scalability take advantage of predictability principle, and you have do to it in a manual way, by using your insights. Here’s why. Cloud scalability vs Cloud elasticity. Vertical Scalability. Scalability helps an application adapt to changing needs by adding or removing resources as needed to meet demands. “cloud scalability” is used in reference to shorter-term traffic demands. If you’re running a small business with 50 employees that all need. I look forward to being corrected for both our sakes, OP. Sep 29, 2023, 5:50 AM. Cloud elasticity is sometimes confused with cloud scalability, often because they’re used interchangeably or talked about in the same sentence. A proactive approach to scale is far less costly than a reactive one. This method is usually used when a single server is experiencing. The company would, therefore, be ready for any scale performance with the process of cloud scalability. EC2 Image Builder. Scalability means that an application or System can handle greater loads by adapting to the user requests (also called Auto-scaling – one of the most important features of the Cloud). GET YOUR VPS. They enable to allocate as many resources as needed for the system to fulfill the workload requirements. Cloud scalability vs cloud elasticity Cloud vendors can provide both scalable and elastic solutions. High Availability. Cloud Elasticity Cloud Scalability; For a brief amount of time, elasticity is only employed to accommodate a workload that fluctuates suddenly up and down. It requires an engineer to manage scaling up and out or down. Elasticity is the ability of a cloud to expand or compress the infrastructural resources.