hsrp negotiation

If you add a second hsrp device to a network with one router, already configured for hsrp (with the highest priority value), will there be a period when it will stop responding to the standby ip and mac when a second hsrp unit comes online regardless of the fact that it will be configured with a lower priority?

Reply to
linguafr
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Well ,if I understand your senario, the standby is becoming active, it sounds like the two routers have lost communication ie routing trouble. Otherwise, we the two are neighbors only the higher priority should be active.

Reply to
sCissOrsRsharP

see Cisco doc

Avoiding HSRP Instability in a Switching Environment with Various Router Platforms

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Reply to
Merv

Sorry, guys, I think my initial post was unclear. The existing router will have the higher priority. I will bring a second router online configured with a lower priority. The question is whether there will be a period after bringing up the second router in which the standby ip will not be reachable during the initial hsrp negotiation?

Reply to
linguafr

I don't see why there would be. A router is active for the VIP until it hears an announcement from another router with higher priority. When the second router comes online it will send out a negotiation broadcast. But the priority will be lower than the existing router, so the existing router will stay active.

Reply to
Barry Margolin

The response from Barry Margolin was absolutely correct. There will be no interuption by adding another standby group router. Just to expand on it:

HSRP has the following states, listed in sequence: 1) Initial 2) Learn 3) Listen 4) Speak 5) Standby 6) Active

If an active HSRP router exists on the network, any joining router goes through the states and remains on standby. If the "preempt" option is specified, the highest priority router becomes the active router. If the "preempt" option is not set, the active router remains active no matter if another router has a higher priority or not. This promotion from standby to active without "preempt" only occurs when the standby router does not receive HRSP hello packets within the hold time and the standby router becomes the active router.

HSRP hello packets are UDP port 1985 multicast packets from the router interface IP address to 224.0.0.2 with at TTL of 1 as defined by RFC 2281.

Reply to
Scott Perry

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