IP SLA for multiple host

Answered Question
May 15th, 2012

Hi

I have a problem

On my router I have configured Cisco EEM, which do next

event manager applet BGP_ISP_DOWN

event track 1 state down

action 1.0 cli command "enable"

action 1.1 cli command "conf t"

action 1.2 cli command "no ip prefix-list own-prefix seq 10 permit 10.10.10.0/24"

action 1.3 cli command "ip prefix-list own-prefix-bee seq 15 permit 10.10.10.0/24"

action 1.4 syslog msg "BGP peer ISP down 10.10.10.0/24 now through ISP2"

and this simple SLA

ip sla 1

icmp-echo 11.11.11.11 source-interface GigabitEthernet0/1.202

timeout 15000

frequency 15

ip sla schedule 1 life forever start-time now

Sometimes host 11.11.11.11 which outside for me, stops responding ICMP(for some reason), but my ISP have a host 11.11.11.12 which UP and respondinng ICMP.

Is there any way ping both hosts 11.11.11.11&11.11.11.12 in one sla?

Or have two sla's in some group?

thanks

I have this problem too.
0 votes
Correct Answer by Cadet Alain about 1 year 11 months ago

Hi,

If you need both hosts down for the tracked object to be down then you need a boolean OR because if you take the truth table for AND it is:

1 and 1 = 1

1 and 0 = 0

0 and 1 = 0

0 and 0 = 0

But the OR is:

1 or 1 = 1

1 or 0 = 1

0 or 1 = 1

0 or 0 = 0

Concerning the syntax it is not the same depending upon IOS version and so surely in yours it should be:

track 1 ip  sla 1 reachability

Regards.

Alain

Correct Answer by rizwanr74 about 1 year 11 months ago

Hi Cadet,

I believe the boolean retun has to be an "and" because of the problem the client is facing that IP-SLA decision is based on just one single return, therefore the boolean has to be an "and".

I hope that you would agree with me.

thanks

Rizwan Rafeek

Correct Answer by Cadet Alain about 1 year 11 months ago

Hi,

yes you can use a boolean track with a OR like this:

ip sla 1

icmp-echo 11.11.11.11 source-interface GigabitEthernet0/1.202

timeout 15000

frequency 15

ip sla schedule 1 life forever start-time now

ip sla 2

icmp-echo 11.11.11.12 source-interface GigabitEthernet0/1.202

timeout 15000

frequency 15

ip sla schedule 2 life forever start-time now

track 1 rtr 1

track 2 rtr 2

track 2  list boolean or

object 1

object 2

event manager applet BGP_ISP_DOWN

event track 3 state down

Regards.

Alain

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Average Rating: 5 (3 ratings)
Krasnoperov Wed, 05/16/2012 - 01:49

seems I dont have track 1 rtr command

Might be you know why?

r1(config)#track 1 ?

  interface    Select an interface to track

  ip           IP protocol

  list         Group objects in a list

  stub-object  Stub tracking object

Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), Version 15.2(1)T1, RELEASE SOFTWARE (fc1)

Correct Answer
Cadet Alain Wed, 05/16/2012 - 03:44

Hi,

If you need both hosts down for the tracked object to be down then you need a boolean OR because if you take the truth table for AND it is:

1 and 1 = 1

1 and 0 = 0

0 and 1 = 0

0 and 0 = 0

But the OR is:

1 or 1 = 1

1 or 0 = 1

0 or 1 = 1

0 or 0 = 0

Concerning the syntax it is not the same depending upon IOS version and so surely in yours it should be:

track 1 ip  sla 1 reachability

Regards.

Alain

Krasnoperov Thu, 05/17/2012 - 01:15

You was right

Multiple objects can also be tracked by means of a list, using a  flexible method for combining objects with Boolean logic. This  functionality includes:

Boolean AND function—When  a tracked list has been assigned a Boolean AND function, each object  defined within a subset must be in an up state, so that the tracked  object can also be in the up state.

Boolean OR function—When  the tracked list has been assigned a Boolean OR function, it means that  at least one object defined within a subset must also be in an up  state, so that the tracked object can also be in the up state.

Correct Answer
rizwanr74 Wed, 05/16/2012 - 00:36

Hi Cadet,

I believe the boolean retun has to be an "and" because of the problem the client is facing that IP-SLA decision is based on just one single return, therefore the boolean has to be an "and".

I hope that you would agree with me.

thanks

Rizwan Rafeek

Cadet Alain Wed, 05/16/2012 - 00:55

Hi,

I think it should be an OR if he wants the tracked  object to be down if both pings fail but not if one only fails.

Tell me what you think about it.

Regards.

Alain

Krasnoperov Wed, 05/16/2012 - 01:42

Thanks, but in my track I need to check that all tracking hosts are down

Correct Answer
Cadet Alain Wed, 05/16/2012 - 00:13

Hi,

yes you can use a boolean track with a OR like this:

ip sla 1

icmp-echo 11.11.11.11 source-interface GigabitEthernet0/1.202

timeout 15000

frequency 15

ip sla schedule 1 life forever start-time now

ip sla 2

icmp-echo 11.11.11.12 source-interface GigabitEthernet0/1.202

timeout 15000

frequency 15

ip sla schedule 2 life forever start-time now

track 1 rtr 1

track 2 rtr 2

track 2  list boolean or

object 1

object 2

event manager applet BGP_ISP_DOWN

event track 3 state down

Regards.

Alain

Krasnoperov Wed, 05/16/2012 - 01:49

seems I dont have track 1 rtr command

Might be you know why?

r1(config)#track 1 ?

  interface    Select an interface to track

  ip           IP protocol

  list         Group objects in a list

  stub-object  Stub tracking object

Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), Version 15.2(1)T1, RELEASE SOFTWARE (fc1)

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Posted May 15, 2012 at 10:50 PM
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Tags: ip, multiple, sla, ip_sla, host
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