HSRP+ EIGRP load sharing

Answered Question
Dec 6th, 2007
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Hi folks,


We have the following network,replace loctn with routers.

HSRP

loctn1 -----------loctn2

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| |

| |

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loctn3 ---loctn4----loctn5


We want to use HSRP for device redundancy and EIGRP would run on WAN.


consider loctn1 is the primary router and loctn2 is the sec router.


Moreover loctn2 routers learns a default route from loctn5 and other specific routes from loctn4


once packets destined to the default route hits the loctn1 router, will EIGRP kick on and through loctn2 reach loctn5?


-Sai.




Correct Answer by Richard Burts about 9 years 5 months ago

Sai


It is difficult to give a precise correct answer without knowing a bit more about the environment that you describe. If loctn5 generates a default route, does it propagate through loctn4 and loctn3 to loctn 1 or is it just to loctn2? What would be the metrics between the various routers?


But if I understand the point of your question to be that loctn1 learns the default route from loctn2 and loctn1 has a packet to forward that uses the default route, then yes loctn1 will forward to loctn2 to reach loctn5.


HTH


Rick

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saimbt Thu, 12/06/2007 - 04:12
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Seems the diagram has got disintegrated. loctn2 connects to loctn5


-Sai.

Correct Answer
Richard Burts Thu, 12/06/2007 - 05:45
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Sai


It is difficult to give a precise correct answer without knowing a bit more about the environment that you describe. If loctn5 generates a default route, does it propagate through loctn4 and loctn3 to loctn 1 or is it just to loctn2? What would be the metrics between the various routers?


But if I understand the point of your question to be that loctn1 learns the default route from loctn2 and loctn1 has a packet to forward that uses the default route, then yes loctn1 will forward to loctn2 to reach loctn5.


HTH


Rick

saimbt Thu, 12/06/2007 - 06:48
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Hi Rick,


I was expecting the same reply from you... I only a confusion about HSRP and EIGRP co-existing.


I had a feeling that once he loctn1 router becomes the pri router.. will the loctn2 router take part in routing.


HSRP will play a role in the election of pri router and the rest routing will be taken care by EIGRP.

Richard Burts Thu, 12/06/2007 - 13:50
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Sai


EIGRP (or any other dynamic routing protocol) can easily exist along with HSRP. There is not anything in HSRP that has any impact on the routing protocol. HSRP has to do with which device will function as the default gateway for end stations on the LAN but does not affect routing. So HSRP will determine that loctn1 will become the active or primary router for that subnet, but HSRP does not make or influence any decision about how the router should forward packets to destinations off the subnet.


HTH


Rick

saimbt Thu, 12/06/2007 - 21:18
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Rick,

Thank you so much... u r a rockstar....

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