Hot Standby Router Protocol (HSRP) is a protocol developed by Cisco which provides high RFC , which are defined in Finding Feature Information; Information About FHRP – HSRP MIB; How to to RFC , which are defined in In computer networking, the Hot Standby Router Protocol (HSRP) is a Cisco proprietary redundancy protocol for establishing a fault-tolerant default gateway. Version 1 of the protocol was described in RFC in
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If multiple groups are used on a single LAN, load splitting can be achieved by distributing hosts among different standby groups. For other media values between 0 and inclusive are valid. For each standby group, a single well-known MAC address is allocated to the group, as well as an IP address. This set is known as an HSRP group or a standby group. If a router sends a Hello message, then receivers should consider that Hello message to be valid for one Holdtime.
If the Hellotime is not configured on a router, then it MAY be learned from the Hello message from the active router.
Solved: hsrp and rfc – Cisco Community
This field is only meaningful in Hello messages. This field describes the current state of the router sending the message.
Cisco protocols First-hop redundancy protocols. It listens for Hello messages from those routers.
This state is entered via a configuration change or when an interface first comes up. In the event that the active router fails, the standby assumes the packet forwarding duties of the active router. This router is known as the active router.
This can be useful for dual branch routers each with a single link back to the gateway. In the case of routers with equal priority the router with the higher IP address wins.
The protocol establishes an association between gateways in order to achieve default gateway failover if the primary gateway becomes inaccessible. A router cannot enter Speak state unless it has the virtual IP address.
When comparing priorities of two different routers, the router with the numerically higher priority wins. It is not compatible with version 1 HSRP.
Hot Standby Router Protocol
If the primary router should fail, the router with the next-highest priority would take over the gateway IP address and answer ARP requests with the same MAC address, thus achieving transparent default gateway failover. This field is used to elect the active and standby routers. It contains the amount of time that the current Hello message should be considered valid. If the Holdtime is not configured on a router, then it MAY be learned from the Hello message from the active router.
HSRP is not a routing protocol as it does not advertise IP routes or affect the routing table in any way. The router sends periodic Hello messages.
Hot Standby Router Protocol – Wikipedia
On a particular LAN, multiple hot standby groups may coexist and overlap. The router knows the virtual IP address, but is neither the active router nor the standby router. In this state the router is still waiting to hear from the active router. The virtual IP address used by this group.
A router which is in active state MUST NOT learn new values for the Hellotime and the Holdtime from other routers, although it may continue to use values which it learned from the previous active router. To minimize network traffic, only the active and the standby routers send periodic HSRP messages once the protocol has completed the election process. If the virtual IP address is not configured on a router, then it MAY be learned from the Hello message from the active router.
This field contains a clear text 8 character reused password. HSRP provides failover services to those hosts.
The router is a candidate to become the next active router and sends periodic Hello messages.