Redundancy is a very important for today’s High Available Networks. So, not to have problem during a failure and for continuous traffic flow, redundancy mechanims are used. These redundany mechanims can be multiple links going to a node, multiple devices on the same role etc. First Hop Redundancy is one of the redundancy mechanisms that provides high available and always on networks. This redundany mechanism creates a redundant architecture, alternative paths on the way to the destination and saves the network from the single point of failure of the first IP router.
For such a mechanism, First Hop Reundancy Protocols are used. There are three wellknown First Hop Redundancy Protocols (FHRPs). These are given below:
You can reach the Cisco Configuration Examples of these FHRP below:
Two of the protocols above, HSRP and GLBP are Cisco Proprietary protocols. You can use GLBP only on Cisco devices. But now you can use HSRP in different vendor devices like Huawei device.
Another protocol, VRRP, is a Standard Based protocol. You can use this protocol in all vendor’s devices, like Juniper, Nokia and Huawei.
The main operation of these First Hop Reundancy mechanims are selecting a key device as Active and send the traffic through it. Beside, provide one more available Backups and turn the traffic flow throuh it during a failure. By duing this, if a single device has problems, traffic is not lost and continues to flow through another backup device.
By the way, a Virtual IP address is used and shared in these mechanims. So, as the gateway, this Virtual IPs are used and the traffic flows independent from any device and physical address.
These are some key differences between these First Hop Redundancy Protocols (FHRPs). We will discuss the key properies of each First Hop Redundancy Protocol in a separate lesson, but here, let’s see the differences of them with a nice table. You can find the differences of HSRP, VRRP and GLBP in the below table. You can analyze, HSRP vs VRRP vs GLBP.