EIGRP recovery across static tunnel

[fsebera]

We have a need to set EIGRP hello/hold timers between hub and spoke peers at different intervals.

The hub and spokes peer across a mGRE tunnel - timers on the mGRE tunnel are set to the max of 65535 seconds (both ends) thus essentially static.

The hub EIGRP hello/hold timers are default at 10/30 (to enable spokes fast failover)

The spokes EIGRP hello/hold timers are 4/12 hours (allows the Hub to stay synced up without hellos from spokes).

The long timers are set to avoid overrunning the hub with keepalives for both mGRE and EIGRP for a large number of spokes as well as processing through traffic.

All works very well until the Hub tunnel is manually shut down. Upon re-enabling the Hub tunnel (no shut), EIGRP on the Hub does not send any hellos to any neighbors thus killing the spokes from peering and communicating.

If this is not an IOS bug perhaps IP SLA could be used to track EIGRP state to correct this strange config?

Is this a possible bug or is my setup jacked ?

Thank you for at least looking!! ♪ ♫

Frank

[paul driver]

Hello,

Are you saying on one side of the eigrp neighbor the hello/dead interval are 10/30 and on the other side its set 4/12 hours!

Seems like  the hubs eigrp dead timer is expiring  before it receives an hello from the spokes.

res

Paul

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[fsebera]

Hey Paul,

When the Hub end of the tunnel is manually shut down, the spokes acknowledge the loss of the EIGRP neighbor.

But upon no shutting the Hub tunnel interface, EIGRP Hub nor Spokes do not send any hello packets at all - based on the debug output.

debug ip eigrp

debug ip eigrp 10 neighbor 172.18.10.1

It seems to me the Hub would at least try to send an initial hello just to start the process but as debug on both ends reveals, no one sends a hello.

Regards

Frank

[paul driver]

Hello fsebera,

Have you tried shut down/up both ends on the tunnel?

Can you post from both ends of the tunnels

show ip eigrp topology active

show ip eigrp neighbors

res

Paul

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[fsebera]

Hey Paul,

more investigation I see this issue

WAN4#clear ip eigrp neighbors tunnel 10

Interface specified: Tunnel10 is not configured under EIGRP

WAN4#sh run int tun10

!

interface Tunnel10

ip address 172.18.10.4 255.255.255.0

ip hello-interval eigrp 10 14400

ip hold-time eigrp 10 43200

ip nhrp map multicast 172.17.10.1

ip nhrp map 172.18.10.1 172.17.10.1

ip nhrp network-id 10

ip nhrp holdtime 65535

ip nhrp nhs 172.18.10.1

ip nhrp registration timeout 65535

tunnel source 172.17.40.1

tunnel destination 172.17.16.1

tunnel key 10

end

WAN4#sh run | b router eigrp

router eigrp 10

network 172.18.10.0 0.0.0.255

distance eigrp 15 255

passive-interface default

no passive-interface Tunnel10

eigrp router-id 172.18.10.4

eigrp stub receive-only

!

!

router eigrp 20

network 172.18.20.0 0.0.0.255

distance eigrp 18 255

passive-interface default

no passive-interface Tunnel20

eigrp router-id 172.18.10.4

eigrp stub receive-only

!

snip

!******************************************

Here are the show comands you asked about:

WAN4#sh ip eigrp top act

EIGRP-IPv4 Topology Table for AS(10)/ID(172.18.10.4)

EIGRP-IPv4 Topology Table for AS(20)/ID(172.18.10.4)

****SPOKE****

WAN4#sh ip eigrp nei

EIGRP-IPv4 Neighbors for AS(10)

EIGRP-IPv4 Neighbors for AS(20)

H    Address         Interfaces    Hold    Uptime    SRTT   RTO    Q   Seq

                                             (sec)                  (ms)              Cnt Num

0    172.18.20.1    Tu20               12    02:03:15       8    1428    0    36

****HUB****

WAN1#sh ip eigrp top act

IP-EIGRP Topology Table for AS(90)/ID(172.16.10.2)

IP-EIGRP topology Table for AS(10)/ID(172.18.10.1)

WAN1#sh ip eigrp nei

IP-EIGRP neighbors for process 90

H    Address          Interface          Hold    Uptime    SRTT    RTO    Q    Seq

                                                  (sec)                   (ms)              Cnt   Num

0    172.16.10.246  Fa0/0.103         13     5w3d            1      200      0     1080

1    172.16.10.253  Fa0/0.100         10     6w3d            1      200      0     1172

IP-EIGRP neighbors for process 10

WAN1#