they all use keepalive timer to detect when the other is down or online.they all create a virtual mac and ip address and finally,.on redundancy, making sure that you have an active path to go out should thee be a disaster,.Under the FHRP, we have the HRSP, VRRP, GLBP and they are all focused So, what is FHRP according to Cisco? First Hop Redundancy Protocol ( FHRP) is IP routing redundancy, designed to allow for transparent fail-over at the first-hop IP router. The mission of FHRP is to make the default gateway redundant.
Cisco mac address 0000.0c9f. full#
These shall be considered in full in the configuration sections Anything can fail but yet the systems stay online because there is full hardware redundancy in the network. There are other kinds of redundancies necessary for the hardware redundancy to be successful and these are logical redundancies which includes the following Here, we try to eliminate any single point of failure to achieve redundancy. In the topology below, the redundancy is on the hardware, the server has 2 network cards, 2 switches and 2 routers for network 10.0.1.0/24, 2 switches and 2 routers for network 10.0.2.0/24, 2 WAN links so, at anytime, if one fails, the other backup takes over. In larger offices /enterprise, the cost will be justified because the cost of an outage will be a lot more expensive than the cost of the redundancy put in place. This is usually common for offices where the cost of adding a redundant device(s) cannot be justified to management. If the router in the branch goes down, the network s down, if the switch goes down, the network is down, if the cable connecting the devices goes down, the network is down, period. Everything here is a single point of failure. This is a simple branch office network connected to an ISP with NO redundancy. In case of a failure, the backup/standby device will take over following the missing of the keepalives from the master/active device.The FHRP devices are exchanging messages to agree which device will act as master/active.The hosts are using the virtual IP address as their default gateway.The default routers share a virtual IP address in the subnet.Meaning, if any single network device fails, another one is right there ready to take over the load without any noticeable change to end users. First-hop redundancy protocols (FHRP) is a class of protocols (HSRP, GLBP)-Cisco-proprietary and VRRP that allows multiple routers on the same subnet to act as a single default router for the host in that subnet.įor the purpose of the CCNA exam, it is enough to understand how they are working and that is: Network redundancy is the process of adding additional network devices to the network so we don’t have any single point of failure.