Join Lazaro Diaz for an in-depth discussion in this video Introducing redundancy protocols, part of CCNA Cert Prep: ICND2.
- Alright, Network Redundancy. Ensures stability on a network. So we're going to take a look at the three redundancy protocols that we're going to use on our network to make sure that, that does exist. Now, one of the first redundancy protocols is HSRP and we also have VRRP and lastly, GLBP. Now they all provide the same type of redundacy. They just work a little bit differently. Three questions that you need to ask yourself when you're deciding to create a redundant network.
How fast can the failover happen? Depending on the redundancy protocol that you use, it could be quicker or it could be slower. So you need to ask that question. The second question you need to know is How does the client know when to switch? Well, during the configurations we will see later on in the course, you'll see that the client will automatically switch over, but again we'll get into a lot more detail when we get into the configuration. Lastly, what if the WAN link fails? Not just your gateway failing but the other side of the router.
Well, there are options that you can configure in these redundancy protocols that will track these particular WAN links. And again, later on in the course, we'll go ahead and get more into detail about these configurations. As far as HSRP it's the acronym Hot Standby Router Protocol. The thing is, it's Cisco proprietary and this is back look at the date, 1994. So we're using a protocol that's been around forever.
Now we're getting tested on it. So because of that, HSRP, is a slow protocol when it comes to hello timers, failovers. It is slower than the others. The good thing about it is, like all these redundancy protocols is that the client automatically will switch over. Alright, but HSRP is one of the slowest of the protocols that we have. VRRP, on the other hand, is Virtual Router Redundancy Protocol and it's multi-vendor and it was created later by the IETF in 1999.
So, we're not stuck with just Cisco routers we can get whatever routers we choose and we can configure this redundancy protocol on there. Also, VRRP is a much faster protocol when it comes to failover than HSRP. That's one of its benefits. And of course, allows non-Cisco routers on the network. So, definitely some people will like run over to VRRP, but we'll see later on in the course how we can make HSRP look and run like VRRP.
One of the last redundancy protocols that we're going to look at is GLBP. It's a Gateway Load Balancing Protocol. Again, Cisco proprietary. So there's a battle between all the vendors and Cisco. So Cisco took over. And this was introduced in 2005, so you can see that everything has been upgraded, I should say, took make it faster, but we'll discuss GLBP in a lot more detail later on. GLBP, since it was created in 2005, has been updated to be faster than HSRP from back then.
So, definitately this is a redundancy protocol that we would like to use because of its speed and its true load balancing features that it has. So these are the three redundancy protocols that we will be looking at HSRP, VRRP, GLBP in a lot more detail and we'll be getting into a lab to be explaining the HSRP protocol.
- LAN switching
- The Spanning-Tree Protocol
- Backing up and restoring Cisco devices
- IP services (FHRP, syslog, GLBP, and SNMP v2 and v3)
- Configuring EIGRP
- IP routing via OSPF
- Setting up wide area networks (WANs) with PPP and frame relay
- Understanding virtual private networks (VPNs)
Using Packet Tracer and cabling, you'll learn how to combine these protocols and technologies to create redundant switch networks that are stable and fast. Along the way, Laz provides practical examples of networking challenges that you'll encounter in the exam and in real life.