DMVPN ipsec tunnel establishment concept question

Hi folks,

R2-------------R1(HUB)--------------------R3

I faced a doubt on ipsec part of the dmvpn. I've got 3 questions:

 As the first packet from R2 has to go via hub since it doesn't now about
 R3's NBMA address.In the mean while that it tries to resolve NMBA address
of R3 , still having glean adjacency , it sends packets through hub.(another
question here is how R2 knows that it should send the packet through hub
???? since all of the routes coming from R1 to R2 have the next-hop of R3).

Second question is how the tunnel establishment works here? An ipsec tunnel
establishes between R2 and R1 for the first packet following with R1 to R3
ipsec tunnel and after R2 and R3 knows about each others NBMA addresses
,they establish ipsec tunnel directly and R2-->R1 ,R1-->R3 ipsec tunnels
will die after a while ? or being up for update exchanges between hub and
spokes?

What is the impact of dmvpn here on voice traffic? from tunnel
establishment point of view? Is the audible voice distortion caused by
switching from spoke-hub-spoke ipsec tunnels to spoke-spoke ipsec tunnels?

Cheers,

Jeremy

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Received on Fri Apr 09 2010 - 12:55:19 ART