Quedas no OSPF.

Prezados, boa tarde.

Estou com um problema em uma rede, o cliente está reclamando de quedas intermitentes pelo que eu pude entender no log do router ele está perdendo adjacência com os router´s mas gostaria de saber o porque dessa queda segue abaixo o log:

GMT -2
Nov 13 10:33:35 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from FULL to DOWN, Neighbor Down: Interface down or detached
Nov 13 10:35:02 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from LOADING to FULL, Loading Done

Nov 15 09:31:37 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from FULL to DOWN, Neighbor Down: Interface down or detached
Nov 15 09:31:37 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from FULL to DOWN, Neighbor Down: Interface down or detached

Nov 15 09:32:54 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from LOADING to FULL, Loading Done
Nov 15 09:33:07 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from LOADING to FULL, Loading Done

Nov 18 05:47:50 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from FULL to DOWN, Neighbor Down: Too many retransmissions
Nov 18 05:48:50 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from DOWN to DOWN, Neighbor Down: Ignore timer expired
Nov 18 05:49:05 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from LOADING to FULL, Loading Done

Nov 18 12:37:59 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from FULL to DOWN, Neighbor Down: Too many retransmissions
Nov 18 12:38:59 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from DOWN to DOWN, Neighbor Down: Ignore timer expired
Nov 18 12:39:22 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from LOADING to FULL, Loading Done

Nov 18 16:32:22 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 18 16:35:51 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from LOADING to FULL, Loading Done

Nov 18 17:31:56 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 18 17:32:55 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from LOADING to FULL, Loading Done

Nov 18 18:08:45 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 18 18:12:09 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from LOADING to FULL, Loading Done
Nov 18 23:48:56 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from FULL to DOWN, Neighbor Down: Too many retransmissions
Nov 18 23:49:56 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from DOWN to DOWN, Neighbor Down: Ignore timer expired
Nov 18 23:50:23 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from LOADING to FULL, Loading Done
Nov 22 02:27:43 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from FULL to DOWN, Neighbor Down: Interface down or detached
Nov 22 02:27:43 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from FULL to DOWN, Neighbor Down: Interface down or detached
Nov 22 02:29:02 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from LOADING to FULL, Loading Done
Nov 22 02:29:13 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from LOADING to FULL, Loading Done



Nov 23 13:33:38 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 23 13:33:38 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 23 13:35:44 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from LOADING to FULL, Loading Done
Nov 23 13:35:57 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from LOADING to FULL, Loading Done

Nov 23 16:41:34 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 23 16:41:35 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.107 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 23 16:41:37 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.101 from FULL to DOWN, Neighbor Down: Dead timer expired

Nov 23 16:42:28 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.107 from LOADING to FULL, Loading Done
Nov 23 16:42:40 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from LOADING to FULL, Loading Done
Nov 23 16:43:00 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.101 from LOADING to FULL, Loading Done

Nov 24 04:27:44 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.101 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 24 04:27:46 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 24 04:27:46 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 24 04:27:46 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from FULL to DOWN, Neighbor Down: Dead timer expired
Nov 24 04:27:47 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.107 from FULL to DOWN, Neighbor Down: Dead timer expired

Nov 24 04:28:11 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.107 from LOADING to FULL, Loading Done
Nov 24 04:28:36 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from LOADING to FULL, Loading Done
Nov 24 04:28:41 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.101 from LOADING to FULL, Loading Done
Nov 24 04:28:55 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from LOADING to FULL, Loading Done
Nov 24 04:29:00 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from LOADING to FULL, Loading Done

Nov 24 05:16:47 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from FULL to DOWN, Neighbor Down: Interface down or detached
Nov 24 05:16:47 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.101 from FULL to DOWN, Neighbor Down: Interface down or detached
Nov 24 05:16:47 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.107 from FULL to DOWN, Neighbor Down: Interface down or detached
Nov 24 05:16:47 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from FULL to DOWN, Neighbor Down: Interface down or detached
Nov 24 05:16:47 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from FULL to DOWN, Neighbor Down: Interface down or detached

Nov 24 05:18:08 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.107 from LOADING to FULL, Loading Done
Nov 24 05:18:10 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.109 from LOADING to FULL, Loading Done
Nov 24 05:18:10 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.100 from LOADING to FULL, Loading Done
Nov 24 05:18:17 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.108 from LOADING to FULL, Loading Done
Nov 24 05:18:40 GMT: %OSPF-5-ADJCHG: Process 2909, Nbr x.x.x.x on Serial1/3.101 from LOADING to FULL, Loading Done

Uma das causas, e mais comuns é um falha de link, ou latência. Se o link estiver com perdas de pacotes e latência muito elevada ele pode perder pacotes hello e gerar esta intermitência.

Estas adjacencias com as interfaces Serial1/3.107, Serial1/3.108 e Serial1/3.109 são ponto a ponto? Ou fazem eleição de DR/BDR?

Poderia coletar alguns segundos de cada um dos 3 debug abaixo?
"debug ip ospf event"
"debug ip ospf hello"
"debug ip ospf adj"

Com eles podemos confirmar se é perda de pacote, latência ou algum outro motivo.

obs. não precisa ser ao mesmo tempo, e cada coleta pode ser de alguns segundos.