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Network Redundancy Transcription

Welcome to our system resilience and fault tolerance module. In this module, we will discuss minimizing our network down time. It is very important for us to maintain our network resource availability. One of the three primary security principles is availability. And if our system goes offline, then we are not maintaining that concept of availability for our users and our customers.

While an attack from an outside or inside threat could place our system offline, a component or device failure could also affect our availability. We should attempt to avoid single points of failure. And once we find a single point of failure, we should put some redundancy in place to make sure that if that component fails.

We will not lose our entire network. As you can see in the picture at the bottom, we have a single file server in the middle that is responsible for all of the different resources on our network. If that file server goes offline for some reason, we will lose access to all of the resources on our network.

You can use redundant servers with fail over to provide server fault tolerance. If our primary server goes offline, all of the data that's being transmitted to that server can automatically be forwarded over to a secondary or backup server. We can either mirror the data that was on the first server to the secondary server so they always have a copy of the same data.

Or we can store this data on essentially located SAN, storage area network or NAS, network attached storage. In our servers, we typically also use redundant components like power supplies. So that way if one power supply goes bad, the second power supply will power the server until an administrator is able to replace the bad power supply.

We can also use server clustering where we group high availability servers together, and then they are seen as a single system. And this is common in server farms. This provides higher availability. It provides very good scalability. And it makes it much easier to manage rather than using individual servers.

You can create a system where all of the servers are active and share in the processing. And this way, tasks are distributed among the servers to increase the efficiency of the system and make it work faster. You can also use failover methodology where the second server is not processing any data unless the primary system goes offline.

Here the primary system would be active and the secondary would be passive. We also want to make sure that we have some redundancy built into our network connections. We can spend a lot of money setting up high availability servers and server clustering. But if our network connection goes offline, then we still have that single point of failure that places all of our users out of service. We should set up a dual backbone with redundant switches for our local area network and routers for our wide area network. This way we can have a redundant primary network path, we can increase our availability and performance. And we will always have at least one path that remains available.

If we want, we can either use both paths for load balancing, or we can just use one path until that one goes down. We would switch over to the second automatically. If we use load balancing, this will enhance our daily performance. But if we decide not to use load balancing, we need to make sure that our single path is still acceptable for the amount of bandwidth we'll need for our daily operations.

Typically these systems will use automated fail over technology Where an administrator does not even have to intervene. The system automatically detects that a part of the network has gone down, and automatically switches to the back up equipment. Meshed apology can be used in environments where availability is particularly important.

Here we are creating multiple independent Paths to create availability, but the cost is very high with the meshed apology. You want to remember from the CISSP exam that the meshed apology creates the most reliable type of network, however it is also the most expensive. This concludes our system resilience and fault tolerance module.

Thank you for watching.