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Traffic Manager


Course Intro
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Cloud-based virtual networks are software based, and they provide a standard way to organize and isolate Virtual Machines running in the cloud. A virtual network controls addressing, DNS settings, security policies, and routing tables.

Virtual Networks which are commonly referred to as “v-nets”, are isolated from one another. Due to the isolation, you can create networks for development, testing, and production that use the same address blocks.

To allow even further isolation, v-nets support subnets, which allow you to segment the network. Subnets will allow you to break out VMs by their purpose, which is common with tiered architectures. For example, if you have an application broken out into front-end and back-end tiers, then you might want to create two subnets, one for the front-end VMs, and another for the back-end tier.

If you're familiar with traditional networking components then you're going to feel right at home working with v-nets. So, if you're looking to learn more, then start in on the first lesson!

Lecture What you'll learn
Intro What will be covered in this course
Overview The componets of virtual networks
Creating a v-net Creating a virtual network part 1
Completing the v-net Creating a virtual network part 2
Application Gateway The application load balancer
User defined routes Using route tables
Traffic Manager DNS based load balancing
Hybrid networking VPNs and express route
Final thoughts Wrapping up the course



Welcome back! We’ve talked about two different load balancing options throughout the course so far. We talked about the Azure Load Balancer, which is a layer 4 load balancer, which basically means it’s a network load balancer. Then we covered Application Gateway, which is a layer 7 load balancer, which means it load balances at the application level.

So now, let’s add a third option into the mix. Traffic Manager is a DNS level load balancer.

Since traffic manager operates at the DNS level it allows you to point your domain name to traffic manager with a CNAME record, and have traffic manager redirect the request the correct endpoint based on whatever mode you’re using.

Traffic manager has three modes of operation, which are Priority, Weighted and Performance.
Let’s run through each option.

The priority option is better known as failover. It works by directing all requests to a primary endpoint unless that endpoint is down, and then it directs to a secondary endpoint.

It’s common to have a backup of an environment in case of failure. That’s where the priority method comes in handy.

The way it works is that you specify a list of endpoints in priority order, and traffic manager will send traffic to the highest priority endpoint that’s available. If you’re thinking about high availability, especially cross-region availability, this is a fantastic option.

The next mode is weighted, which is similar to round robin in that the intent is to evenly distribute requests. So requests are evenly distributed across the different endpoints at random, however the chance of any given endpoint being selected is based on weighted values that you define for each endpoint. If you want an even distribution, then assign equal weights to all the endpoints. Being able to change the weights gives a lot of flexibility! And it
s a great way to perform canary deployments, as well as application migrations.


The final mode is performance mode, and this is where you have geographically separated endpoints, and traffic manager will select the best one per request based on latency.
By having your endpoints cross region, and using performance based routing you can ensure that your end-users are getting the best user experience possible, because they’ll be directed to the endpoint with the lowest latency, for them. This tends to be the “closest” endpoint, however it’s not a rule.


Okay, that’s going to wrap up this lesson. This was a brief lesson, however hopefully this give you a high enough overview to start diving in to learn more.

In the next lesson we’ll cover hybrid networking options. So if you’re ready to keep learning, then let’s get started in the next lesson!



About the Author
Ben Lambert
Software Engineer
Learning Paths

Ben Lambert is a software engineer and was previously the lead author for DevOps and Microsoft Azure training content at Cloud Academy. His courses and learning paths covered Cloud Ecosystem technologies such as DC/OS, configuration management tools, and containers. As a software engineer, Ben’s experience includes building highly available web and mobile apps. When he’s not building software, he’s hiking, camping, or creating video games.