887G Cellular 0 interface not going up without interesting traffic in DMVPN

[canero]

Hello,

We are configuring 887G router as a DMVPN Spoke device, and configure the 3G Cellular interface as backup of the ADSL interface. In our tests, we observe that if Adsl Atm0 interface is up, and we pull the ADSL cable, the Cellular interface is working properly.

But after this test, if we just reload the router, i.e. we boot the router with ADSL interface is down, we observe that without pinging the GRE tunnel endpoint  the Cellular interface never comes up. After we start a single ping the tunnel destination ip everything is working properly. We think the the GRE protocol, or the NHRP protocol on the tunnel interface should trigger the Tunnel formation, but not observing as exptected.

On the 887G router there's only a static route pointing to the GRE Endpoint IP address, but instead of this host based route we give a default route, the tunnel is formed without starting a ping.

How can we make the tunnel through the Cellular interface form automatically, since this situation in some scenarios need console access to the spoke device?

We thought of  a IP Sla track that would work every 10 seconds to ping the Tunnel endpoint, but this may not be the best choice,

Thanks in Advance,

Best Regards,

[andrew.prince]

Enable tunnel keepalives.

int tun#

keepalive 1 3

HTH>

[canero]

Hello Andrew,

Since we are using DMVPN, we thought of using  gre tunnel keepalives, but the attached document specifically say that tunnel keepalive not supported if gre over ipsec is used. Does it match or is it possible that this restriction may have changed?

Thanks for your recommendation, hope it is supported,

interface Tunnel1

description Hub_Conn_To_ATM_3G

bandwidth 1000

ip address 200.200.200.1 255.255.255.0

no ip redirects

ip mtu 1436

ip nhrp authentication den123

ip nhrp map multicast dynamic

ip nhrp network-id 200000

ip nhrp holdtime 300

ip nhrp shortcut

ip nhrp redirect

ip rip advertise 5

no ip split-horizon

tunnel source GigabitEthernet0/0/3

tunnel mode gre multipoint

tunnel key 200000

tunnel protection ipsec profile dmvpnprofile shared

[andrew.prince]

Hey - generally when I read "not supported" i take that to mean just because it says its not supported, but the command is still available in the IOS.

With that said quickly reading the basic DMVPN config, it already has something that can be used = DPD, Dead Peer Detection???

HTH>

[nihilpatel]

Hi guys,

I am having same type of issue with 887G as Canero...

Please see the following...

I am having some strange issue with 887G router as routes drops out from routing table during idle timing.

We  have configured DSL as a priority and Wireless (BGP) as secondary  routes....everything works fine for few days where DSL act as a priority  and Wireless as a backup, but if I check routing table after few days I  always find routes for wireless is missing.

When I check logging information, it says "hold time expired" and connection dropped along with following error.

"open failed: Connection timed out; remote host not responding"

Firstly,  I wonder why this has dropped eventhough it was working fine for few  days. Secondly, neither cellular nor tunnels were dropped

As soon as I do "shut" and "no shut" to the cellular...everything comes back again...

Any help would be grately appreciated..