IP SLA Reachability Issue - Unstable

kamal_123 · ‎12-01-2019

Hi All,

I have the following configured and ever since applying it my logs were filling up with below log messages. Is something amiss in the config causing this or my timer/threshold the issue? From my investigations I don't think the remote IP is ever becoming unreachable and is always up.

track 1 ip sla 1 reachability
ip sla 1
icmp-echo 10.x.x.197 source-ip 10.x.x.198
vrf xxx
threshold 3000
timeout 3000
frequency 3
ip sla schedule 1 life forever start-time now

track 1 ip sla 1 reachability

HSRP is configured as well.

*Sep 26 00:55:40.068: %TRACK-6-STATE: 1 ip sla 1 reachability Down -> Up
*Sep 26 00:55:40.658: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Standby -> Active
*Sep 26 11:21:23.115: %TRACK-6-STATE: 1 ip sla 1 reachability Up -> Down
*Sep 26 11:21:23.295: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Active -> Speak
*Sep 26 11:21:26.347: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Speak -> Standby
*Sep 26 11:21:28.134: %TRACK-6-STATE: 1 ip sla 1 reachability Down -> Up
*Sep 26 11:21:28.848: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Standby -> Active
*Sep 28 12:27:49.517: %TRACK-6-STATE: 1 ip sla 1 reachability Up -> Down
*Sep 28 12:27:49.976: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Active -> Speak
*Sep 28 12:27:53.123: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Speak -> Standby
*Sep 28 16:51:20.029: %TRACK-6-STATE: 1 ip sla 1 reachability Down -> Up
*Sep 28 16:51:20.135: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Standby -> Active
*Oct 2 00:26:00.116: %TRACK-6-STATE: 1 ip sla 1 reachability Up -> Down
*Oct 2 00:26:00.664: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Active -> Speak
*Oct 2 00:26:03.753: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Speak -> Standby
*Oct 2 00:26:05.116: %TRACK-6-STATE: 1 ip sla 1 reachability Down -> Up
*Oct 2 00:26:05.183: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Standby -> Active
*Oct 23 14:54:32.861: %TRACK-6-STATE: 1 ip sla 1 reachability Up -> Down
*Oct 23 14:54:33.505: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Active -> Speak
*Oct 23 14:54:36.771: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Speak -> Standby
*Oct 23 14:54:37.862: %TRACK-6-STATE: 1 ip sla 1 reachability Down -> Up
*Oct 23 14:54:38.098: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Standby -> Active
*Nov 6 23:56:18.736: %TRACK-6-STATE: 1 ip sla 1 reachability Up -> Down
*Nov 6 23:56:18.898: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Active -> Speak
*Nov 6 23:56:21.915: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Speak -> Standby
*Nov 6 23:56:23.755: %TRACK-6-STATE: 1 ip sla 1 reachability Down -> Up
*Nov 6 23:56:24.355: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Standby -> Active
*Nov 8 13:39:31.413: %TRACK-6-STATE: 1 ip sla 1 reachability Up -> Down
*Nov 8 13:39:32.105: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Active -> Speak
*Nov 8 13:39:35.227: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Speak -> Standby
*Nov 8 13:39:56.413: %TRACK-6-STATE: 1 ip sla 1 reachability Down -> Up
*Nov 8 13:39:56.691: %HSRP-5-STATECHANGE: GigabitEthernet0/0/2 Grp 3 state Standby -> Active

kamal_123 · ‎12-03-2019

up

Georg Pauwen · ‎12-04-2019

Hello,

what is the purpose of the IP SLA ? What are the two IP addresses used in the SLA ?

icmp-echo 10.x.x.197 source-ip 10.x.x.198

icmp-echo should ideally be an IP address beyond the local network. Can you clarify your topology ?

kamal_123 · ‎12-04-2019

Hi Georg,

Thanks for your reply. The purpose is to track the WAN link, if it is down, HSRP will flip to the standby router that has another WAN link.

the IP addresses used is for the point to point link between CE and PE so they are .197 & .198 /30 addresses.

Regards,

Georg Pauwen · ‎12-05-2019

Hello,

it is better to track a remote IP address. Try the config below (interfaces and IP addresses are arbitrary, and yours are likely different):

R1

track 1 ip sla 1 reachability
!
interface GigabitEthernet0/0
ip address 192.168.1.1 255.255.255.0
standby 1 ip 192.168.1.3
standby 1 priority 110
standby 1 preempt
standby 1 track 1 decrement 20
!
ip sla 1
icmp-echo 8.8.8.8
frequency 5
!
ip sla monitor schedule 1 life forever start-time now

R2

interface GigabitEthernet0/0
ip address 192.168.1.2 255.255.255.0
standby 1 ip 192.168.1.3
standby 1 priority 100