CCNP Certification / BCMSN Examination Tutorial: Getting going With HSRP
Outlined in RFC 2281, HSRP is really a Cisco-proprietary protocol by which routers are place into an HSRP router group. As well as dynamic routing protocols and STP, HSRP is taken into account a significant-availability community support, considering the fact that all 3 have an almost speedy cutover to your secondary path when the principal path is unavailable.
On the list of routers will probably be selected as the principal (“Lively”, in HSRP terminology), Which Most important will deal with the routing even though another routers are in standby, Completely ready to handle the load if the primary router results in being unavailable. With this fashion, HSRP guarantees a substantial community uptime, as it routes IP website traffic without the need of depending on an individual router.
The hosts applying HSRP like a gateway don’t know the particular IP or MAC addresses on the routers in the group. They’re communicating with a pseudorouter, a “virtual router” created through the HSRP configuration. This virtual router will likely have a virtual MAC and IP adddress also.
The standby routers aren’t just likely to be sitting down there, nevertheless! By configuring various HSRP groups on one interface, HSRP load balancing could be attained.
Right before we reach the greater State-of-the-art HSRP configuration, we much better have a simple a single started! We’ll be using a two-router topology below, and Understand that one particular or both of those routers could be multilayer switches too. For ease of examining, I’m intending to check with them only as routers.
R2 and R3 will equally be configured to get in standby team 5. The virtual router may have an IP deal with of 172.twelve.23.ten /24. All hosts in VLAN one hundred really should use this tackle as their default gateway.
R2(config)#interface ethernet0
R2(config-if)#standby five ip 172.twelve.23.ten
R3(config)#interface ethernet0
R3(config-if)#standby 5 ip 172.12.23.10
The display command for HSRP is exhibit standby, and it’s the primary command you need to operate though configuring and troubleshooting HSRP. Permit’s operate it on each routers and compare success.
R2#demonstrate standby
Ethernet0 – Group 토토검증 five
Neighborhood condition is Standby, priority 100
Hellotime 3 sec, holdtime ten sec
Future hi sent in 0.776
Digital IP address is 172.twelve.23.10 configured
Active router is 172.twelve.23.3, precedence a hundred expires in nine.568
Standby router is local
one state modifications, final condition adjust 00:00:22
R3#demonstrate standby
Regional point out is Active, priority 100
Subsequent good day sent in 2.592
Energetic router is community
Standby router is 172.twelve.23.two expires in 8.020
Digital mac handle is 0000.0c07.ac05
2 state modifications, past condition change 00:02:08
We are able to see that R3 has become selected as being the Active router (“nearby condition is Active”), the virtual router’s IP is 172.12.23.ten, and R2 is definitely the standby router.
There are several HSRP values that you just’ll will need to alter once in a while. Let's say we want R2 to be the Active router alternatively? Can we alter the MAC handle of the Digital router? I’ll remedy These concerns in the next element of the HSRP tutorial!