Re: BFD neighbors down

pslovinsky · ‎12-09-2011

Hi guys,

i have problem with BFD. BFD neighbors are permanently down. No way to bring them up.

Setup:

Two routers (TTR255 - 2911and IBR255 - 3945(HWIC FE)) are connected via one ethernet link. Routing protocol EIGRP. Routers are configured for VRF-lite using subinterfaces(VLAN 1516,1517,1518). BFD ais enabled on EIGRP adress families and also under corresponding subinterface.

I am using IOS 150-1.M7 and also try 152-2.T. I have DATA license.

Does anybody have same problem?

For more details see attached files.

Thanks, Pato

Peter Paluch · ‎12-09-2011

Hello Patrik,

This is an interesting issue. Please give me a day or so to emulate your config on real devices and come back with my observations. The VRF-aware BFD should be supported on IOSes starting with versions 15.0M.

I assume that the EIGRP itself is working well and adjacencies are being built as appropriate, just the BFD support does not seem to come up - am I correct here?

Best regards,

Peter

pslovinsky · ‎12-12-2011

Yes, you are correct, EIGRP adjacencies are up and traffic is passing link without any troubles.

Best regards,

Patrik

Peter Paluch · ‎12-12-2011

Hi Pato,

I've replicated the key parts of your config on 1841 routers in my lab. I'm running Advanced IP Services, IOS version 15.1(4)M2. I can not replicate the problem, however: the BFD neighbors came up as expected, I had no issues in the whole config coming up on the first attempt.

Please see the following output of the configurations and show commands:

R1 is the "TTR255":

ip vrf ADMIS

rd 1:3

!

ip vrf OPS

rd 1:1

!

ip vrf SUP

rd 1:2

!

interface FastEthernet0/1

no ip address

duplex auto

speed auto

!

interface FastEthernet0/1.1516

description OPS VLAN - prepoj na IBR255 Fa0/0

bandwidth 4000

encapsulation dot1Q 1516

ip vrf forwarding OPS

ip address 172.21.101.86 255.255.255.248

no ip proxy-arp

bfd interval 200 min_rx 200 multiplier 4

!

interface FastEthernet0/1.1517

description SUP VLAN - prepoj na IBR255 Fa0/0

bandwidth 4000

encapsulation dot1Q 1517

ip vrf forwarding SUP

ip address 172.21.191.190 255.255.255.248

no ip proxy-arp

bfd interval 200 min_rx 200 multiplier 4

!

interface FastEthernet0/1.1518

description ADMIS VLAN - prepoj na IBR255 Fa0/0

bandwidth 4000

encapsulation dot1Q 1518

ip vrf forwarding ADMIS

ip address 172.16.160.30 255.255.255.248

no ip proxy-arp

bfd interval 200 min_rx 200 multiplier 4

!

router eigrp 1

!

address-family ipv4 vrf OPS autonomous-system 100

bfd interface FastEthernet0/1.1516

network 172.21.101.86 0.0.0.0

network 172.21.191.226 0.0.0.0

network 172.21.191.255 0.0.0.0

passive-interface default

no passive-interface FastEthernet0/1.1516

eigrp router-id 172.21.191.255

exit-address-family

!

address-family ipv4 vrf SUP autonomous-system 100

bfd interface FastEthernet0/1.1517

network 172.21.191.190 0.0.0.0

network 172.21.191.234 0.0.0.0

passive-interface default

no passive-interface FastEthernet0/1.1517

eigrp router-id 172.21.191.255

exit-address-family

!

address-family ipv4 vrf ADMIS autonomous-system 100

bfd interface FastEthernet0/1.1518

network 172.16.160.30 0.0.0.0

network 172.21.191.242 0.0.0.0

passive-interface default

no passive-interface FastEthernet0/1.1518

eigrp router-id 172.21.191.255

exit-address-family

passive-interface default

shutdown

R1#show bfd neighbors

NeighAddr LD/RD RH/RS State Int

172.16.160.25 1/6 Up Up Fa0/1.1518

172.21.101.81 5/2 Up Up Fa0/1.1516

172.21.191.185 2/4 Up Up Fa0/1.1517

R1#show bfd neighbors detail

NeighAddr LD/RD RH/RS State Int

172.16.160.25 1/6 Up Up Fa0/1.1518

Session state is UP and using echo function with 200 ms interval.

OurAddr: 172.16.160.30

Local Diag: 0, Demand mode: 0, Poll bit: 0

MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 4

Received MinRxInt: 1000000, Received Multiplier: 4

Holddown (hits): 0(0), Hello (hits): 1000(690)

Rx Count: 698, Rx Interval (ms) min/max/avg: 1/1000/873 last: 544 ms ago

Tx Count: 691, Tx Interval (ms) min/max/avg: 756/1000/883 last: 424 ms ago

Elapsed time watermarks: 0 0 (last: 0)

Registered protocols: EIGRP

Uptime: 00:10:09

Last packet: Version: 1 - Diagnostic: 0

State bit: Up - Demand bit: 0

Poll bit: 0 - Final bit: 0

Multiplier: 4 - Length: 24

My Discr.: 6 - Your Discr.: 1

Min tx interval: 1000000 - Min rx interval: 1000000

Min Echo interval: 200000

NeighAddr LD/RD RH/RS State Int

172.21.101.81 5/2 Up Up Fa0/1.1516

Session state is UP and using echo function with 200 ms interval.

OurAddr: 172.21.101.86

Local Diag: 0, Demand mode: 0, Poll bit: 0

MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 4

Received MinRxInt: 1000000, Received Multiplier: 4

Holddown (hits): 0(0), Hello (hits): 1000(695)

Rx Count: 697, Rx Interval (ms) min/max/avg: 1/1000/875 last: 176 ms ago

Tx Count: 697, Tx Interval (ms) min/max/avg: 4/1004/874 last: 520 ms ago

Elapsed time watermarks: 0 0 (last: 0)

Registered protocols: EIGRP

Uptime: 00:10:09

Last packet: Version: 1 - Diagnostic: 0

State bit: Up - Demand bit: 0

Poll bit: 0 - Final bit: 0

Multiplier: 4 - Length: 24

My Discr.: 2 - Your Discr.: 5

Min tx interval: 1000000 - Min rx interval: 1000000

Min Echo interval: 200000

NeighAddr LD/RD RH/RS State Int

172.21.191.185 2/4 Up Up Fa0/1.1517

Session state is UP and using echo function with 200 ms interval.

OurAddr: 172.21.191.190

Local Diag: 0, Demand mode: 0, Poll bit: 0

MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 4

Received MinRxInt: 1000000, Received Multiplier: 4

Holddown (hits): 0(0), Hello (hits): 1000(690)

Rx Count: 695, Rx Interval (ms) min/max/avg: 1/1000/877 last: 644 ms ago

Tx Count: 691, Tx Interval (ms) min/max/avg: 756/1000/882 last: 424 ms ago

Elapsed time watermarks: 0 0 (last: 0)

Registered protocols: EIGRP

Uptime: 00:10:09

Last packet: Version: 1 - Diagnostic: 0

State bit: Up - Demand bit: 0

Poll bit: 0 - Final bit: 0

Multiplier: 4 - Length: 24

My Discr.: 4 - Your Discr.: 2

Min tx interval: 1000000 - Min rx interval: 1000000

Min Echo interval: 200000

R1#

R2 is the "IBR255":

ip vrf ADMIS

rd 1:3

!

ip vrf OPS

rd 1:1

!

ip vrf SUP

rd 1:2

!

interface FastEthernet0/0

no ip address

duplex auto

speed auto

!

interface FastEthernet0/0.1516

description OPS VLAN - prepoj na TTR255 Gi0/1

bandwidth 4000

encapsulation dot1Q 1516

ip vrf forwarding OPS

ip address 172.21.101.81 255.255.255.248

no ip proxy-arp

bfd interval 200 min_rx 200 multiplier 4

!

interface FastEthernet0/0.1517

description SUP VLAN - prepoj na TTR255 Gi0/1

bandwidth 4000

encapsulation dot1Q 1517

ip vrf forwarding SUP

ip address 172.21.191.185 255.255.255.248

no ip proxy-arp

bfd interval 200 min_rx 200 multiplier 4

!

interface FastEthernet0/0.1518

description ADMIS VLAN - prepoj na TTR255 Gi0/1

bandwidth 4000

encapsulation dot1Q 1518

ip vrf forwarding ADMIS

ip address 172.16.160.25 255.255.255.248

no ip proxy-arp

bfd interval 200 min_rx 200 multiplier 4

!

router eigrp 1

!

address-family ipv4 vrf OPS autonomous-system 100

bfd interface FastEthernet0/0.1516

network 172.21.101.81 0.0.0.0

network 172.21.101.97 0.0.0.0

network 172.21.182.226 0.0.0.0

network 172.21.182.255 0.0.0.0

passive-interface default

no passive-interface FastEthernet0/0.1516

eigrp router-id 172.21.182.255

exit-address-family

!

address-family ipv4 vrf SUP autonomous-system 100

bfd interface FastEthernet0/0.1517

network 172.21.182.234 0.0.0.0

network 172.21.191.185 0.0.0.0

network 172.21.192.185 0.0.0.0

passive-interface default

no passive-interface FastEthernet0/0.1517

eigrp router-id 172.21.182.255

exit-address-family

!

address-family ipv4 vrf ADMIS autonomous-system 100

bfd interface FastEthernet0/0.1518

network 172.16.160.9 0.0.0.0

network 172.16.160.25 0.0.0.0

network 172.21.182.242 0.0.0.0

passive-interface default

no passive-interface FastEthernet0/0.1518

eigrp router-id 172.21.182.255

exit-address-family

passive-interface default

shutdown

R2#show bfd neighbors

NeighAddr LD/RD RH/RS State Int

172.16.160.30 6/1 Up Up Fa0/0.1518

172.21.101.86 2/5 Up Up Fa0/0.1516

172.21.191.190 4/2 Up Up Fa0/0.1517

R2#show bfd nei details

NeighAddr LD/RD RH/RS State Int

172.16.160.30 6/1 Up Up Fa0/0.1518

Session state is UP and using echo function with 200 ms interval.

OurAddr: 172.16.160.25

Local Diag: 0, Demand mode: 0, Poll bit: 0

MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 4

Received MinRxInt: 1000000, Received Multiplier: 4

Holddown (hits): 0(0), Hello (hits): 1000(820)

Rx Count: 816, Rx Interval (ms) min/max/avg: 1/3384/882 last: 208 ms ago

Tx Count: 826, Tx Interval (ms) min/max/avg: 1/1000/871 last: 548 ms ago

Elapsed time watermarks: 0 0 (last: 0)

Registered protocols: EIGRP

Uptime: 00:11:46

Last packet: Version: 1 - Diagnostic: 0

State bit: Up - Demand bit: 0

Poll bit: 0 - Final bit: 0

Multiplier: 4 - Length: 24

My Discr.: 1 - Your Discr.: 6

Min tx interval: 1000000 - Min rx interval: 1000000

Min Echo interval: 200000

NeighAddr LD/RD RH/RS State Int

172.21.101.86 2/5 Up Up Fa0/0.1516

Session state is UP and using echo function with 200 ms interval.

OurAddr: 172.21.101.81

Local Diag: 0, Demand mode: 0, Poll bit: 0

MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 4

Received MinRxInt: 1000000, Received Multiplier: 4

Holddown (hits): 0(0), Hello (hits): 1000(821)

Rx Count: 824, Rx Interval (ms) min/max/avg: 1/4608/875 last: 20 ms ago

Tx Count: 826, Tx Interval (ms) min/max/avg: 1/1000/872 last: 800 ms ago

Elapsed time watermarks: 0 0 (last: 0)

Registered protocols: EIGRP

Uptime: 00:11:45

Last packet: Version: 1 - Diagnostic: 0

State bit: Up - Demand bit: 0

Poll bit: 0 - Final bit: 0

Multiplier: 4 - Length: 24

My Discr.: 5 - Your Discr.: 2

Min tx interval: 1000000 - Min rx interval: 1000000

Min Echo interval: 200000

NeighAddr LD/RD RH/RS State Int

172.21.191.190 4/2 Up Up Fa0/0.1517

Session state is UP and using echo function with 200 ms interval.

OurAddr: 172.21.191.185

Local Diag: 0, Demand mode: 0, Poll bit: 0

MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 4

Received MinRxInt: 1000000, Received Multiplier: 4

Holddown (hits): 0(0), Hello (hits): 1000(816)

Rx Count: 816, Rx Interval (ms) min/max/avg: 1/3944/882 last: 952 ms ago

Tx Count: 822, Tx Interval (ms) min/max/avg: 1/1000/876 last: 488 ms ago

Elapsed time watermarks: 0 0 (last: 0)

Registered protocols: EIGRP

Uptime: 00:11:46

Last packet: Version: 1 - Diagnostic: 0

State bit: Up - Demand bit: 0

Poll bit: 0 - Final bit: 0

Multiplier: 4 - Length: 24

My Discr.: 2 - Your Discr.: 4

Min tx interval: 1000000 - Min rx interval: 1000000

Min Echo interval: 200000

R2#

Of course, the EIGRP adjacencies are up:

R1#show ip eigrp vrf ADMIS nei

EIGRP-IPv4 Neighbors for AS(100) VRF(ADMIS)

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

0 172.16.160.25 Fa0/1.1518 10 00:16:48 8 300 0 5

R1#show ip eigrp vrf OPS nei

EIGRP-IPv4 Neighbors for AS(100) VRF(OPS)

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

0 172.21.101.81 Fa0/1.1516 10 00:16:55 16 300 0 4

R1#show ip eigrp vrf SUP nei

EIGRP-IPv4 Neighbors for AS(100) VRF(SUP)

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

0 172.21.191.185 Fa0/1.1517 14 00:16:58 8 300 0 5

R1#

R2#show ip eigrp vrf ADMIS nei

EIGRP-IPv4 Neighbors for AS(100) VRF(ADMIS)

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

0 172.16.160.30 Fa0/0.1518 11 00:17:36 4 300 0 5

R2#show ip eigrp vrf OPS nei

EIGRP-IPv4 Neighbors for AS(100) VRF(OPS)

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

0 172.21.101.86 Fa0/0.1516 14 00:17:41 124 1116 0 4

R2#show ip eigrp vrf SUP nei

EIGRP-IPv4 Neighbors for AS(100) VRF(SUP)

H Address Interface Hold Uptime SRTT RTO Q Seq

(sec) (ms) Cnt Num

0 172.21.191.190 Fa0/0.1517 10 00:17:43 4 300 0 5

R2#

So, the behavior as observed by you is strange indeed. Do your EIGRP adjacencies come up? Would you mind upgrading your IOS to a 15.1M train or newer to see if this is not a software bug? Try avoiding the 'T' trains if possible.

Best regards,

Peter

Peter Paluch · ‎12-12-2011

Pato,

One more observation: I am somewhat confused by this output from your show bfd nei detail:

TTR255#show bfd neighbors details

NeighAddr LD/RD RH/RS State Int

172.16.160.25 6/0 Down Down Gi0/1.1518

OurAddr: 172.16.160.30

Local Diag: 0, Demand mode: 0, Poll bit: 0

MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 4

Received MinRxInt: 0, Received Multiplier: 0

Holddown (hits): 0(0), Hello (hits): 1000(7452)

Rx Count: 0, Rx Interval (ms) min/max/avg: 0/0/0 last: 80491968 ms ago

Tx Count: 7452, Tx Interval (ms) min/max/avg: 756/1000/882 last: 412 ms ago

Elapsed time watermarks: 0 0 (last: 0)

Registered protocols: EIGRP

Last packet: Version: 1 - Diagnostic: 0

State bit: AdminDown - Demand bit: 0

Poll bit: 0 - Final bit: 0

Multiplier: 0 - Length: 0

My Discr.: 0 - Your Discr.: 0

Min tx interval: 0 - Min rx interval: 0

Min Echo interval: 0

I was not able to find out why the "AdminDown" state is displayed, and it seems to be an indication of something that is perhaps causing your problem.

Best regards,

Peter