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No route after Interface change in VRF

Hi Everyone,

I have had a couple of strange incidents where changing a physical interface or ip address on an interface causes routing problems. We are running ASR9010 on IOS-XR 4.2.3

Case 1:

Changed a physical interface gi0/0/0/1.12 to BE21.12 on a vrf.

I lost static routes and had to remove and re-apply.

Case2:

Changed the IP address to a different network 172.17.254.126/27 to 172.27.254.126/27

ARP OK and ping from VRF or local device in other VRF OK, however host on connected interface cannot be pinged from across MPLS. Connected route is carried across MPLS OK. We will be trying to remove the entire interface and vrf config and re-apply.

EDIT: We re-applied config after removing and commiting. It is now working.

Any ideas or clues?

Cheers

Mike

2 Replies 2

Jean-Christophe Rode
Cisco Employee
Cisco Employee

Hello Michael,

It's hard to say without data to illustrate the issue... but for the static route issue, this might be due to

CSCue35606 were a static route might stop working when you don't specify the interface in the static route (only the next hop) and when the local interface goes down so that you now learn that net hop from another MPLS-VPN PE which is connected to that next hop too. When the local interface comes back up and the next hop is reachable locally again, traffic matching the static route will be dropped.

There is a SMU for it so I'd recommend installing the latest SMUs for 4.2.3.

Thanks,

JC

Thanks,

The basic thing for case 2 is:

Customer --> VRF Gateway- Ping OK

RP/0/RSP0/CPU0:macq-syd-intel2-asr9010-01#ping vrf BACKUP-MANAGEMENT 172.27.254.99

Fri Feb 14 12:42:49.771 EST

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.27.254.99, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

Server --> MPLS --> VRF Gateway - Ping OK

>  ping routing-instance BACKUP_SERVERS 172.27.254.126

PING 172.27.254.126 (172.27.254.126): 56 data bytes

64 bytes from 172.27.254.126: icmp_seq=0 ttl=255 time=1.126 ms

64 bytes from 172.27.254.126: icmp_seq=1 ttl=255 time=1.029 ms

64 bytes from 172.27.254.126: icmp_seq=2 ttl=255 time=1.097 ms

64 bytes from 172.27.254.126: icmp_seq=3 ttl=255 time=0.998 ms

64 bytes from 172.27.254.126: icmp_seq=4 ttl=255 time=1.032 ms

^C

--- 172.27.254.126 ping statistics ---

5 packets transmitted, 5 packets received, 0% packet loss

round-trip min/avg/max/stddev = 0.998/1.056/1.126/0.047 ms

Server --> MPLS --> VRF --> Customer - Destination Unreachable

> ping routing-instance BACKUP_SERVERS 172.27.254.99    

PING 172.27.254.99 (172.27.254.99): 56 data bytes

76 bytes from 124.47.128.30: Destination Net Unreachable

Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst

4  5  00 0054 940d   0 0000  40  01 3404 172.28.91.252  172.27.254.99

76 bytes from 124.47.128.30: Destination Net Unreachable

Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst

4  5  00 0054 a361   0 0000  40  01 24b0 172.28.91.252  172.27.254.99

76 bytes from 124.47.128.30: Destination Net Unreachable

Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst

4  5  00 0054 a8ae   0 0000  40  01 1f63 172.28.91.252  172.27.254.99

76 bytes from 124.47.128.30: Destination Net Unreachable

Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst

4  5  00 0054 ad11   0 0000  40  01 1b00 172.28.91.252  172.27.254.99

76 bytes from 124.47.128.30: Destination Net Unreachable

Vr HL TOS  Len   ID Flg  off TTL Pro  cks      Src      Dst

4  5  00 0054 b5ab   0 0000  40  01 1266 172.28.91.252  172.27.254.99

--- 172.27.254.99 ping statistics ---

9 packets transmitted, 0 packets received, 100% packet loss

RP/0/RSP0/CPU0:macq-syd-intel2-asr9010-01#ping vrf BACKUP-MANAGEMENT 172.27.254.99

Fri Feb 14 12:42:49.771 EST

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.27.254.99, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms

RP/0/RSP0/CPU0:macq-syd-intel2-asr9010-01#    sh arp vrf M2MGMT23509001                    

Fri Feb 14 12:56:57.313 EST

-------------------------------------------------------------------------------

0/1/CPU0

-------------------------------------------------------------------------------

Address         Age        Hardware Addr   State      Type  Interface

172.27.254.99   00:14:08   0050.5682.66c0  Dynamic    ARPA  Bundle-Ether2.12

172.27.254.124  03:08:07   0050.5682.565c  Dynamic    ARPA  Bundle-Ether2.12

172.27.254.126  -          6c9c.ed03.8eb2  Interface  ARPA  Bundle-Ether2.12

RP/0/RSP0/CPU0:macq-syd-intel2-asr9010-01#    sh arp vrf M2MGMT23509001

Fri Feb 14 12:57:25.328 EST

VRF Gateway --> MPLS --> Server - Ping OK

RP/0/RSP0/CPU0:macq-syd-intel2-asr9010-01#ping vrf M2MGMT23509001 172.28.91.19

Fri Feb 14 13:00:13.402 EST

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.28.91.19, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

RP/0/RSP0/CPU0:macq-syd-intel2-asr9010-01#sh run router bgp 17477 vrf M2MGMT23509001

Fri Feb 14 13:02:11.425 EST

router bgp 17477

vrf M2MGMT23509001

  rd auto

  label-allocation-mode per-vrf

  address-family ipv4 unicast

   redistribute connected

  !

!

!

RP/0/RSP0/CPU0:macq-syd-intel2-asr9010-01#sho route vrf M2MGMT23509001                                       

Fri Feb 14 13:03:46.700 EST

Codes: C - connected, S - static, R - RIP, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

       i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area, su - IS-IS summary null, * - candidate default

       U - per-user static route, o - ODR, L - local, G  - DAGR

       A - access/subscriber, - FRR Backup path

Gateway of last resort is not set

B    10.117.24.0/23 [20/0] via 172.27.0.110 (nexthop in vrf BACKUP-MANAGEMENT), 1d01h

B    10.135.0.0/24 [20/0] via 172.27.0.110 (nexthop in vrf BACKUP-MANAGEMENT), 1d01h

B    10.135.2.0/24 [20/0] via 172.27.0.110 (nexthop in vrf BACKUP-MANAGEMENT), 1d01h

C    172.27.254.96/27 is directly connected, 2d02h, Bundle-Ether2.12

L    172.27.254.126/32 is directly connected, 2d02h, Bundle-Ether2.12

B    172.28.1.240/28 [200/0] via 125.7.35.120 (nexthop in vrf default), 6d22h

B    172.28.91.0/24 [200/0] via 125.7.35.120 (nexthop in vrf default), 6d22h

B    172.28.92.0/24 is directly connected, 1d01h, Bundle-Ether4 (nexthop in vrf BACKUP-SERVER)

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