Delivering Applications

Application Delivery Architecture is a crucial aspect of modern software development and deployment. It plays a significant role in ensuring the efficient delivery of applications to end-users. With the increasing demand for high-performance applications and the need for seamless user experiences, organizations are investing heavily in optimizing their application delivery architecture.

In a nutshell, application delivery architecture refers to the framework and infrastructure that enables the delivery of applications to end-users. It encompasses various components, including networking, load balancing, security, and scalability. The ultimate goal is to ensure that applications are delivered efficiently, reliably, and securely, regardless of the user’s location or device.

Example: AVI Networks

Avi networks offer load balancing as a hyper-scale application delivery architecture and optimization service. Hyperscale can be defined as the ability of the architect to scale as demand increases for the system. At the same time, application demand changes, so the system architecture is automatically based on traffic load. The Avi load balancer requires no capacity pre-provisioning, making it a perfect cloud application delivery platform.

When companies buy load balancers ( application delivery platforms ), they buy 2 x 10G load balancer appliances and check they can support x of Secure Sockets Layer ( SSL ) connections—probably purchased without application analytics, causing the appliance to be under or over-utilized. Avi scaling feature enables application delivery services to be elastically scaled out and scaled in on-demand. They are maximizing network resources and enabling hyper-scale application delivery architecture.

Before you proceed, you may find the following useful:

1. Virtual Firewalls.
2. Scaling Load Balancers
3. What is BGP Protocol in Networking
4. Application Delivery Network
5. Full Proxy
6. A10 Networks

Back to basics with a load balancer

A load balancer is a physical or virtual appliance that sits before your servers and routes client requests across all servers. A load balancer has a lot of additional capabilities that can fulfill those requests in a manner that maximizes speed and capacity utilization and ensures that no one server is overworked, which could degrade application performance.

It does all of this with a load balancer algorithm. Consider a load balancer to act as a reverse proxy and distribute network or application traffic across several servers. Load balancers increase applications’ capacity (concurrent users) and reliability.

High Availability and Low Latency

One of the critical components of application delivery architecture is the network infrastructure. A robust network infrastructure is essential for ensuring high availability and low latency. This involves deploying multiple data centers in geographically diverse locations, interconnected with high-speed links. Organizations can achieve improved performance, fault tolerance, and resilience by distributing application delivery across multiple data centers.

Load balancing is another critical aspect of application delivery architecture. It involves distributing network traffic across multiple servers to optimize resource utilization and ensure high availability. Load balancers act as intermediaries between the user and the application servers, intelligently routing requests to the most suitable server based on server load, response time, and server health. This helps to prevent any single server from becoming overwhelmed and ensures that applications are accessible and responsive.

Security is paramount

Security is a paramount concern in application delivery architecture. With increasing cyber threats, organizations must implement robust security measures to protect sensitive data and prevent unauthorized access. This includes implementing firewalls, intrusion detection systems, and encryption technologies to safeguard the application infrastructure and user data. Additionally, application delivery controllers can provide advanced security features such as web application firewalls and SSL/TLS termination to protect against common web-based attacks.

Scalability

Scalability is another important consideration in application delivery architecture. As user demand fluctuates, organizations must scale their application infrastructure accordingly to accommodate increasing traffic. This can be achieved through horizontal scaling, where additional servers are added to handle the increased load, or vertical scaling, which involves upgrading existing servers with more powerful hardware. By adopting a scalable architecture, organizations can ensure that their applications can handle peak traffic without compromising performance or user experience.

The Need for Application Delivery Architecture

Today’s application – less deterministic

Application flows are becoming less deterministic, and architects can no longer rely on centralized appliances for efficient application delivery. Avi Networks overcome this problem by offering a scale-out application delivery controller. Avi describes their product as a cloud application delivery platform. The core of its technology is based on analyzing application and network telemetry.

From this information, the application delivery appliance can efficiently balance the load. The additional information gained from analytic gathering arms Avi networks against unpredictable application experiences and “Black Friday” events. Traditional load balancers route user requests or sessions to servers based on the request’s characteristics. Avi operates with the same principles and adds additional value by analyzing other telemetry parameters of request characteristics.

A lot has changed in the data center with emerging trends such as mobile and cloud. Customers are looking to redesign the data center with increasing user experience. As a result, the quality of user experience becomes increasingly unpredictable and inconsistent. Load balancers should be analytics-driven, but unfortunately, many enterprise customers do not have that type of network assessment. Avi networks aim to bring the enterprise the additional benefits of analytically driven load-balancing decisions.

Hyperscale application delivery: How does it work?

They offer a scalable load balancer; the critical point is that it is driven by analytics. It tracks real-time users, servers, and network telemetry and feeds all this information to databases that influence the application’s decision. Application visibility and load balancing are combined under one hood creating an elastic software load balancer.

In terms of scalability, if the application gets too many requests, it can spin up new virtual load balancers in VM format to deal with requests and additional loads. You do not have to provision upfront. This type of use case is ideal for “Black Friday” events. But you can see the load in advance since you are tracking the real-time analytics. They typically run in VM format, so you do not need additional hardware. Mid-sized companies are getting the same benefits as massive hyper-scale companies—an ideal solution for retail companies dealing with sporadic peak loads at random intervals.

Avi does not implement any caps on input. So, if you have a short period of high throughput, it is not capped – invoicing is backdated based on traffic peak events. In addition, Avi does not have controls to limit the appliance, so if you need additional capacity in the middle of the night, it will give it to you.

Control and Data Plane

If you want to deal with a scale-out architecture, you need a data plane that can scale out, too. Something must control that data plane, i.e., the control plane. So Avi consists of two components. The first component is the scale-out controller, which has a REST API. The second component is the Service Engine ( SE ).

SE is similar to an HTTP proxy. However, they are terminating one TCP session and opening a different session to the server, so you have to do Source NAT. Source NAT changes the source address in the IP header of a packet. It may also change the source port in the TCP/UDP headers.

With this method, the client IP addresses are Assigned to the load balancer’s local IP. This ensures that server responses go through the correct load-balancing device. However, it also hides the original client’s source IP address.

And since you are sitting at layer 7, you can intercept and do what you want with the HTTP headers. This is not a problem with an HTTP application as they can put the client IP in the HTTP header – X-Forwarded-For (XFF) HTTP header field. The XFF HTTP Header field is the de facto standard for identifying the originating client IP address that is connected to the web server via an HTTP proxy or load balancer. From this, you can tell who the source client is, and because they know the client telemetry, they can do various TCP optimizations for high latency links, high band links, low bandwidth, and low latency links.

The SE sites in the data plane provide essential load-balancing services. Depending on throughput requirements, you can have as many SEs as you want—up to 200. Potentially, you can carve up the SE into admin domains so that sure tenants can access an exact amount of SE regardless of network throughput.  

SE assignments can be fixed or flexible. You can spin up the virtual machine for load-balancing services or have a certain VM per tenant. For example, the DEV test can have a couple of dedicated engines. It depends on the resources you want to dedicate.

Application delivery architecture is critical to modern software development and deployment. Organizations can deliver applications efficiently, reliably, and securely by optimizing the network infrastructure, implementing load balancing, ensuring robust security measures, and adopting scalable practices. As technology continues to evolve, application delivery architecture will remain a key factor in ensuring the success of businesses in the digital age