Hello Deo
As Rene suggested, high availability can be deployed with multiple technologies depending upon what you want to achieve. Here are some thoughts that might help you out:
- High availability can be achieved using two or more devices to perform a task.
- Setting up two ASAs for example in high availability mode, or two servers mirroring each other.
- Configuring switches in various high availability arrangements like StackWIse, vPC, and VSS.
- Applying First Hop Redundancy Protocols (FHRPs) like HSRP, VRRP, and GLBP to enable multiple devices to act as default gateways.
- High availability can also be achieved using technologies that use multiple physical links like EtherChannel.
- Routing can be configured to introduce Equal Cost MultiPath (ECMP) Routing delivering high availability and resistance to the network.
- High availability can also be achieved by implementing the appropriate power supplies, making sure that you have redundant power supplies per device, and UPS systems delivering power to your network devices.
- High availability can also be delivered by designing your network with duplicate data centers, where if one data center fails, the other will take over fully. This is a higher-level design aspect, and assumes that your organization has multiple sites.
- Network design delivers high availability by using either a spine and leaf architecture, which is inherently redundant, or a 3 tier campus network design as shown in this lesson.
These are just some of the areas in which high availability can be implemented into network design. If you would like us to expand on any particular area, let us know…
I hope this has been helpful!
Laz