OSPF on Firepower Cluster with FTD 6.2.3

[hm7]

Hello,

does anyone have experience with OSPF on a FTD cluster?

I have two FP 4120 running FXOS 2.3(1.99) and FTD 6.2.3.83 on top. The FTDs are configured as a cluster and I am using Firepower Management Center to configure it.

The FTD cluster should replace a pair of ASA 5585-Xs so the two FP 4120s are not carrying any live traffic yet.

Both the old ASAs as well as the new FPs are connected to a pair of Cat6506s and they are supposed to use OSPF to exchange their routing information.

On the ASAs that was no problem at all. The OSPF was running stable and without any issues.

On the FTDs, however, as soon as I enable OSPF on the cluster in a VLAN that contains both 6506s I get OSPF error messages like:

Neighbor Down: Ignore timer expired

Neighbor Down: Too many retransmissions

If it is just the 6506s in that VLAN the OSPF remains stable.

From the FTDs I have OSPF also enabled towards a pair of HP12500s and this OSPF session remains stable. The HPs act as one logical device, however.

So I am thinking that it might be a design issue with the 6506s. I might need two separate transfer networks. One transfer network from FTD chassis #1 to Cat6506 #1 and another transfer network from FTD chassis #2 to Cat6506 #2.

Any help is appreciated!

cheers,

Harald

[balaji.bandi · Accepted solution]

As per the OSPF messages concerns

Neighbor Down: Ignore timer expired

Neighbor Down: Too many retransmissions

Your re-transmission problem is mainly caused by an MTU mismatch, Can you  check this on both equipment using

show system mtu and You  can also disable MTU check for OSFP using ip ospf mtu-ignore under the interface connected interface to other device, if other device support same please issue same command.

if still have issue, please post the topology and configuration.

[bcoverstone]

I would like to add something to this.

I am running a pair of Firepower 1010 with the FTD firmware loaded, and when I fail them over, about 1 out of 3 times the OSPF session to our primary router gets the too many retransmissions and drops the whole thing causing about a minute of downtime until they can resync. So one might think that the issue is a dropped packet during the failover, and maybe it is. But I found that if I set "ip ospf mtu-ignore" on the interface going to the Firepower, I was able to fail them over 8 times without the OSPF session getting dropped.

So I feel there may be times when this has nothing to do with MTU, because the FTD never has a problem until the failover occurs.

[hm7]

The MTU thing always comes up but I don't think its the problem here. I have attached a simple drawing of the setup. Here are the config bits:

FTD-Config:

!
interface Port-channel10.520
vlan 520
nameif inside-po10.520
cts manual
propagate sgt preserve-untag
policy static sgt disabled trusted
security-level 0
ip address 172.23.248.254 255.255.255.248
!
interface Port-channel20
nameif extern-po20
cts manual
propagate sgt preserve-untag
policy static sgt disabled trusted
security-level 0
no ip address
!
interface Port-channel20.700
vlan 700
nameif extern-po20.700
cts manual
propagate sgt preserve-untag
policy static sgt disabled trusted
security-level 0
ip address 172.23.248.113 255.255.255.248
!
interface Port-channel20.701
vlan 701
nameif extern-po20.701
cts manual
propagate sgt preserve-untag
policy static sgt disabled trusted
security-level 0
ip address 172.23.248.121 255.255.255.248
!
mtu inside-po10 9000
mtu inside-po10.520 9000
mtu extern-po20 9000
mtu extern-po20.700 9000
mtu extern-po20.701 9000
!
router ospf 1
network 172.23.248.112 255.255.255.248 area 0
network 172.23.248.120 255.255.255.248 area 0
network 172.23.248.248 255.255.255.248 area 0
log-adj-changes
!

#############################################

HP12500 config:

interface Ten-GigabitEthernet3/9/0/16
port link-mode bridge
description fp2-rz3-eth2
port link-type trunk
port trunk permit vlan 1 520
port link-aggregation group 200
#
interface Ten-GigabitEthernet4/9/0/16
port link-mode bridge
description fp2-rz4-eth2
port link-type trunk
port trunk permit vlan 1 520
port link-aggregation group 201
#
interface Bridge-Aggregation200
description fp2-rz3-Po10
port link-type trunk
port trunk permit vlan 1 520
link-aggregation mode dynamic
#
interface Bridge-Aggregation201
description fp2-rz4-Po10
port link-type trunk
port trunk permit vlan 1 520
link-aggregation mode dynamic
#
interface Vlan-interface520
mtu 9000
ip address 172.23.248.249 255.255.255.248
ospf cost 200
ospf network-type broadcast
#
ospf 1 router-id 172.20.20.201
default-route-advertise always
import-route static
silent-interface all
undo silent-interface Vlan-interface520
area 0.0.0.0
network 172.20.0.0 0.3.255.255
#

#############################################

rtr1-config

!

ip vrf psp-aws
rd 65500:8
!
vlan 700
name fp-rtr3-vrf-psp-aws
!
vlan 701
name fp-rtr4-vrf-psp-aws
!
interface Port-channel20
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 700,701
switchport mode trunk
mtu 9216
!
interface TenGigabitEthernet1/3
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 700,701
switchport mode trunk
mtu 9216
channel-group 20 mode active
!
interface Vlan700
mtu 9000
ip vrf forwarding psp-aws
ip address 172.23.248.118 255.255.255.248
ip flow ingress
!
router ospf 8 vrf psp-aws
router-id 172.23.249.158
log-adjacency-changes
auto-cost reference-bandwidth 20000
capability vrf-lite
redistribute static metric-type 1 subnets
redistribute bgp 65500 subnets route-map from-vrf-psp-aws
passive-interface default
no passive-interface Vlan700
network 172.23.248.112 0.0.0.7 area 0
!

#############################################

rtr2-config

!
ip vrf psp-aws
rd 65500:8
!
vlan 700
name fp-rtr3-vrf-psp-aws
!
vlan 701
name fp-rtr4-vrf-psp-aws
!
interface Port-channel20
description fp2-rz4-po20
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 700,701
switchport mode trunk
mtu 9216
!
interface TenGigabitEthernet1/3
description fp2-rz4-eth3
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 700,701
switchport mode trunk
mtu 9216
channel-group 20 mode active
!
interface Vlan701
description Transfer fp-extern <-> rtr-extern VRF psp-aws
mtu 9000
ip vrf forwarding psp-aws
ip address 172.23.248.126 255.255.255.248
ip flow ingress
!
router ospf 8 vrf psp-aws
router-id 172.23.249.157
log-adjacency-changes
auto-cost reference-bandwidth 20000
capability vrf-lite
redistribute static metric-type 1 subnets
redistribute bgp 65500 subnets route-map from-vrf-psp-aws
passive-interface default
no passive-interface Vlan701
network 172.23.248.120 0.0.0.7 area 0
network 172.23.249.152 0.0.0.7 area 0
!

#############################################

OSPF debugs from rtr2:

Nov 15 14:10:24.909: %OSPF-5-ADJCHG: Process 8, Nbr 172.23.248.254 on Vlan701 from LOADING to DOWN, Neighbor Down: Too many retransmissions
Nov 15 14:11:24.909: OSPF: 172.23.248.254 address 172.23.248.121 on Vlan701 is dead
Nov 15 14:11:24.909: OSPF: 172.23.248.254 address 172.23.248.121 on Vlan701 is dead, state DOWN
Nov 15 14:11:24.909: %OSPF-5-ADJCHG: Process 8, Nbr 172.23.248.254 on Vlan701 from DOWN to DOWN, Neighbor Down: Ignore timer expired
Nov 15 14:11:24.909: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:11:24.909: OSPF: DR/BDR election on Vlan701
Nov 15 14:11:24.909: OSPF: Elect BDR 0.0.0.0
Nov 15 14:11:24.909: OSPF: Elect DR 172.23.249.157
Nov 15 14:11:24.909: DR: 172.23.249.157 (Id) BDR: none
Nov 15 14:11:31.225: OSPF: 2 Way Communication to 172.23.248.254 on Vlan701, state 2WAY
Nov 15 14:11:31.225: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:11:31.225: OSPF: DR/BDR election on Vlan701
Nov 15 14:11:31.225: OSPF: Elect BDR 0.0.0.0
Nov 15 14:11:31.225: OSPF: Elect DR 172.23.249.157
Nov 15 14:11:31.225: DR: 172.23.249.157 (Id) BDR: none
Nov 15 14:11:31.225: OSPF: Vlan701 Nbr 172.23.248.254: Prepare dbase exchange
Nov 15 14:11:31.225: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x39D opt 0x52 flag 0x7 len 32
Nov 15 14:11:31.225: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:11:31.225: OSPF: DR/BDR election on Vlan701
Nov 15 14:11:31.225: OSPF: Elect BDR 0.0.0.0
Nov 15 14:11:31.225: OSPF: Elect DR 172.23.249.157
Nov 15 14:11:31.225: DR: 172.23.249.157 (Id) BDR: none
Nov 15 14:11:31.225: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0xFEA opt 0x52 flag 0x7 len 32 mtu 9000 state EXSTART
Nov 15 14:11:31.225: OSPF: First DBD and we are not SLAVE
Nov 15 14:11:31.229: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x39D opt 0x52 flag 0x2 len 1452 mtu 9000 state EXSTART
Nov 15 14:11:31.229: OSPF: NBR Negotiation Done. We are the MASTER
Nov 15 14:11:31.229: OSPF: Vlan701 Nbr 172.23.248.254: Summary list built, size 569
Nov 15 14:11:31.229: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x39E opt 0x52 flag 0x3 len 1452
Nov 15 14:11:31.229: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x39E opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:11:31.229: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x39F opt 0x52 flag 0x3 len 1452
Nov 15 14:11:31.233: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x39F opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:11:31.233: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x3A0 opt 0x52 flag 0x3 len 1452
Nov 15 14:11:31.233: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x3A0 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:11:31.233: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x3A1 opt 0x52 flag 0x3 len 1452
Nov 15 14:11:31.233: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x3A1 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:11:31.233: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x3A2 opt 0x52 flag 0x3 len 1452
Nov 15 14:11:31.237: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x3A2 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:11:31.237: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x3A3 opt 0x52 flag 0x3 len 1452
Nov 15 14:11:31.237: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x3A3 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:11:31.237: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x3A4 opt 0x52 flag 0x3 len 1452
Nov 15 14:11:31.237: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x3A4 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:11:31.237: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x3A5 opt 0x52 flag 0x3 len 1452
Nov 15 14:11:31.241: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x3A5 opt 0x52 flag 0x2 len 52 mtu 9000 state EXCHANGE
Nov 15 14:11:31.241: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x3A6 opt 0x52 flag 0x1 len 52
Nov 15 14:11:31.241: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x3A6 opt 0x52 flag 0x0 len 32 mtu 9000 state EXCHANGE
Nov 15 14:11:31.241: OSPF: Exchange Done with 172.23.248.254 on Vlan701
Nov 15 14:11:31.241: OSPF: Send LS REQ to 172.23.248.254 length 1008 LSA count 84
Nov 15 14:11:31.725: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 88 LSA count 1
Nov 15 14:11:36.033: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:11:36.033: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:11:38.837: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:11:40.305: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:11:40.305: OSPF: DR/BDR election on Vlan701
Nov 15 14:11:40.305: OSPF: Elect BDR 172.23.248.254
Nov 15 14:11:40.305: OSPF: Elect DR 172.23.249.157
Nov 15 14:11:40.305: DR: 172.23.249.157 (Id) BDR: 172.23.248.254 (Id)
Nov 15 14:11:40.305: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:11:40.305: OSPF: DR/BDR election on Vlan701
Nov 15 14:11:40.305: OSPF: Elect BDR 172.23.248.254
Nov 15 14:11:40.305: OSPF: Elect DR 172.23.249.157
Nov 15 14:11:40.305: DR: 172.23.249.157 (Id) BDR: 172.23.248.254 (Id)
Nov 15 14:11:40.581: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:11:40.581: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:11:45.293: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:11:45.293: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:11:50.061: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:11:50.061: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:11:52.813: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:11:54.433: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:11:54.785: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:11:54.785: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:11:59.537: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:11:59.537: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:04.393: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:04.393: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:09.253: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:09.253: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:14.122: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:14.122: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:18.626: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:18.626: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:18.838: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:22.462: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:22.494: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 100 LSA count 2
Nov 15 14:12:23.434: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:23.434: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:26.462: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:26.494: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:28.106: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:28.106: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:30.462: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:30.494: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 136 LSA count 3
Nov 15 14:12:32.462: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:32.494: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:33.074: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:33.074: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:36.462: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:36.494: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:37.646: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:37.646: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:42.218: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:42.218: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:44.474: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:45.258: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:45.294: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:12:45.334: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 76 LSA count 1
Nov 15 14:12:47.170: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:47.170: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:48.946: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 172 LSA count 1
Nov 15 14:12:52.002: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:52.002: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:12:56.598: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:12:56.598: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:13:00.514: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:13:01.390: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:13:01.390: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:13:04.510: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:13:06.310: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:13:06.310: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:13:09.974: OSPF: Build router LSA for area 0, router ID 172.23.249.244, seq 0x8000293E, process 1
Nov 15 14:13:10.002: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 100 LSA count 1
Nov 15 14:13:11.274: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:13:11.274: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:13:14.522: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 64 LSA count 1
Nov 15 14:13:16.014: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:13:16.014: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:13:20.914: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:13:20.914: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:13:25.626: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:13:25.626: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:13:30.578: OSPF: Vlan701 Nbr: 172.23.248.254: Retransmitting LS REQ
Nov 15 14:13:30.578: OSPF: Send LS REQ to 172.23.248.254 length 996 LSA count 83
Nov 15 14:13:35.294: OSPF: Killing nbr 172.23.248.254 on Vlan701 due to excessive (25) retransmissions
Nov 15 14:13:35.294: OSPF: 172.23.248.254 address 172.23.248.121 on Vlan701 is dead, state DOWN
Nov 15 14:13:35.294: %OSPF-5-ADJCHG: Process 8, Nbr 172.23.248.254 on Vlan701 from LOADING to DOWN, Neighbor Down: Too many retransmissions
Nov 15 14:13:35.294: OSPF: Vlan701 Nbr 172.23.248.254: Clean-up dbase exchange
Nov 15 14:13:35.294: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:13:35.294: OSPF: DR/BDR election on Vlan701
Nov 15 14:13:35.294: OSPF: Elect BDR 0.0.0.0
Nov 15 14:13:35.294: OSPF: Elect DR 172.23.249.157
Nov 15 14:13:35.294: DR: 172.23.249.157 (Id) BDR: none
Nov 15 14:14:35.295: OSPF: 172.23.248.254 address 172.23.248.121 on Vlan701 is dead
Nov 15 14:14:35.295: OSPF: 172.23.248.254 address 172.23.248.121 on Vlan701 is dead, state DOWN
Nov 15 14:14:35.295: %OSPF-5-ADJCHG: Process 8, Nbr 172.23.248.254 on Vlan701 from DOWN to DOWN, Neighbor Down: Ignore timer expired
Nov 15 14:14:35.295: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:14:35.295: OSPF: DR/BDR election on Vlan701
Nov 15 14:14:35.295: OSPF: Elect BDR 0.0.0.0
Nov 15 14:14:35.295: OSPF: Elect DR 172.23.249.157
Nov 15 14:14:35.295: DR: 172.23.249.157 (Id) BDR: none
Nov 15 14:14:40.303: OSPF: 2 Way Communication to 172.23.248.254 on Vlan701, state 2WAY
Nov 15 14:14:40.303: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:14:40.303: OSPF: DR/BDR election on Vlan701
Nov 15 14:14:40.303: OSPF: Elect BDR 0.0.0.0
Nov 15 14:14:40.303: OSPF: Elect DR 172.23.249.157
Nov 15 14:14:40.303: DR: 172.23.249.157 (Id) BDR: none
Nov 15 14:14:40.303: OSPF: Vlan701 Nbr 172.23.248.254: Prepare dbase exchange
Nov 15 14:14:40.307: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x516 opt 0x52 flag 0x7 len 32
Nov 15 14:14:40.307: OSPF: Neighbor change Event on interface Vlan701
Nov 15 14:14:40.307: OSPF: DR/BDR election on Vlan701
Nov 15 14:14:40.307: OSPF: Elect BDR 0.0.0.0
Nov 15 14:14:40.307: OSPF: Elect DR 172.23.249.157
Nov 15 14:14:40.307: DR: 172.23.249.157 (Id) BDR: none
Nov 15 14:14:40.307: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x3A7 opt 0x52 flag 0x7 len 32 mtu 9000 state EXSTART
Nov 15 14:14:40.307: OSPF: First DBD and we are not SLAVE
Nov 15 14:14:40.307: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x516 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXSTART
Nov 15 14:14:40.307: OSPF: NBR Negotiation Done. We are the MASTER
Nov 15 14:14:40.307: OSPF: Vlan701 Nbr 172.23.248.254: Summary list built, size 569
Nov 15 14:14:40.307: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x517 opt 0x52 flag 0x3 len 1452
Nov 15 14:14:40.311: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x517 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:14:40.311: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x518 opt 0x52 flag 0x3 len 1452
Nov 15 14:14:40.311: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x518 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:14:40.311: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x519 opt 0x52 flag 0x3 len 1452
Nov 15 14:14:40.311: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x519 opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:14:40.311: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x51A opt 0x52 flag 0x3 len 1452
Nov 15 14:14:40.315: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x51A opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:14:40.315: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x51B opt 0x52 flag 0x3 len 1452
Nov 15 14:14:40.315: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x51B opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:14:40.315: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x51C opt 0x52 flag 0x3 len 1452
Nov 15 14:14:40.315: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x51C opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:14:40.315: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x51D opt 0x52 flag 0x3 len 1452
Nov 15 14:14:40.319: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x51D opt 0x52 flag 0x2 len 1452 mtu 9000 state EXCHANGE
Nov 15 14:14:40.319: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x51E opt 0x52 flag 0x3 len 1452
Nov 15 14:14:40.319: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x51E opt 0x52 flag 0x2 len 52 mtu 9000 state EXCHANGE
Nov 15 14:14:40.319: OSPF: Send DBD to 172.23.248.254 on Vlan701 seq 0x51F opt 0x52 flag 0x1 len 52
Nov 15 14:14:40.319: OSPF: Rcv DBD from 172.23.248.254 on Vlan701 seq 0x51F opt 0x52 flag 0x0 len 32 mtu 9000 state EXCHANGE
Nov 15 14:14:40.319: OSPF: Exchange Done with 172.23.248.254 on Vlan701
Nov 15 14:14:40.319: OSPF: Send LS REQ to 172.23.248.254 length 1020 LSA count 85
Nov 15 14:14:40.803: OSPF: Rcv LS UPD from 172.23.248.254 on Vlan701 length 88 LSA count 1

#############################################

[hm7]

I think I might have found the solution... it probably is a MTU problem after all.

The link between rtr1 and rtr2 still runs on a MTU of 1500 because it was never changed.

So increasing the MTU to 9216 on the 10G link between routers might remedy the situation...

[balaji.bandi]

Good hear back and found MTU was the issue, if the solution works please close the thread with solution please.