hold timer and hello timer in eigrp

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Mar 23rd, 2009
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Hi everybody!

Do hold timer and hello timer should match in order to establish neighbor relationship between two routers running eigrp?


Thanks a lot!

Correct Answer by Richard Burts about 8 years 3 months ago

Yes the router will advertise bandwidth and delay based on its own local interface.


HTH


Rick

Correct Answer by Richard Burts about 8 years 3 months ago

1) EIGRP uses Dual all the time. Dual is the basic algorithm that EIGRP uses to select routes and to guarantee that the path chosen is loop free. Note that feasible successor is only a part of what Dual does.


2) when r2 sends an update it will advertise the lowest bandwidth of any link along the path and will advertise the sum of all the delays along the path.


HTH


Rick

Correct Answer by Richard Burts about 8 years 3 months ago

It is helpful to understand that while OSPF does require that the timers match as a requirement for forming a neighbor relationship, EIGRP does not have this requirement. EIGRP will successfully form neighbor relationship between routers that have different hold timers and hello timers.


HTH


Rick

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Correct Answer
Richard Burts Mon, 03/23/2009 - 20:40
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It is helpful to understand that while OSPF does require that the timers match as a requirement for forming a neighbor relationship, EIGRP does not have this requirement. EIGRP will successfully form neighbor relationship between routers that have different hold timers and hello timers.


HTH


Rick

sarahr202 Mon, 03/23/2009 - 20:55
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Thanks Rick !

If you don't mind, i have two more questions:


1)Does eigrp use " dual" only when there is no feasible successor?


2)r1-----------r2-10.0.0.0 (both running eigrp)

When r2 sends update to r1 about 10.0.0.0 What value of bandwidth and delay is included in the update?


thanks a lot !








































Correct Answer
Richard Burts Tue, 03/24/2009 - 04:42
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1) EIGRP uses Dual all the time. Dual is the basic algorithm that EIGRP uses to select routes and to guarantee that the path chosen is loop free. Note that feasible successor is only a part of what Dual does.


2) when r2 sends an update it will advertise the lowest bandwidth of any link along the path and will advertise the sum of all the delays along the path.


HTH


Rick

sarahr202 Tue, 03/24/2009 - 08:48
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HI Rick!

thanks for your reply.


r1s0----------s0r2f0a-10.10.10.0/24


Subnet 10.10.10.0/24 is directly connected, so r2 sends cumulative delay and minimum bandwidth along the way in its update. Here 10.10.10./24 is directly connected, therefore what would be the delay and bandwidth value? i mean will router sends delay and bandwidth off its fo interface in this case?

Thanks a lot!

Correct Answer
Richard Burts Tue, 03/24/2009 - 12:14
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Yes the router will advertise bandwidth and delay based on its own local interface.


HTH


Rick

carl_townshend Wed, 04/29/2009 - 06:52
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so if R2 sends an update, will it add the delay and BW of the FE and S0 interface ? or just the SO interface ?

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