Embedded event manager

Unanswered Question
Oct 28th, 2009

Hi team

I had open a post in lan switching for this particular problem and the expert from that forum has given the solution of embedded event manager so i need a help from this forum.

The probelm defination is==

Cisco 6509 (Core switch) connected to firewall on uplink side and on downlink its connected to 2 diffrent Cisco 6509 switches (Distribution) layer.All these links have been configured as Routed link and not as SVI.Now issue is when both the downlinks (coming from both distribution) switches go down i want to make the uplink from core to firewall to go down so that other core switch will take over and transfer teh traffic.

Attached diagram has details.tried configuring HSRP between 2 core switches but as teh links are routed link HSRP not working and both switches remain master but as on oppsite side Juniper firewall NSRP is implemented 2nd firewall not responding and core-2 ==fw2 link not transfer traffic.now when both the links of core go down link from core1-fw1 should go down so Fw2 will get active and will send traffic on link betwene core2-firewall2..please let me know what kind of configursation is required in EEM..

I have this problem too.
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Joe Clarke Wed, 10/28/2009 - 20:40

I think this policy should work for you. It requires two environment variables to be set before registering:

intf_watch_interfaces : Comma-separated list of interfaces to watch

intf_watch_uplink : Name of the uplink interface

For example:

event manager environment intf_watch_interfaces GigabitEthernet4/1,GigabitEthernet4/2

event manager environment intf_watch_uplink GigabitEthernet6/1

sameermunj Wed, 10/28/2009 - 20:53


thanks for the reply.

really speaking i am very new to this EEM so dont know how this code will be written and how it will be applied.In real time scenario my down links are Ten gig 9/1 &y 9/3 while my uplink is Gig 1/2.can you guide me further to let me know how the code will look like and how it will be applied.My requirement when both 9/1 -9/3 go down Gig1/2 should come down and when any of teh downlink comes up Gig1/2 should come up.

u can also share the possible configuration guides for the same if u have any.

Thanks for the help.

Joe Clarke Wed, 10/28/2009 - 21:36

Do the following (assuming you have a disk0:):

mkdir disk0:/policies

copy tftp://x.x.x.x/sl_intf_watch.tcl disk0:/policies

config t

event manager directory user policy disk0:/policies

event manager environment intf_watch_interfaces TenGigabitEthernet9/1,TenGigabitEthernet9/3

event manager environment intf_watch_uplink GigabitEthernet1/2

event manager policy sl_intf_watch.tcl

Where x.x.x.x is the IP address of your TFTP server.

After that, the policy is registered, and waiting for the interfaces to go down.

sameermunj Wed, 10/28/2009 - 22:08


So i need to download the TCL file attached in previous post and need to upload the same in my disk:0 via tftp and then need to put those 4 comamnds mentioned above.i have a doubt here.in the comamnds mentioned above we just mention the interfaces to be watched then where exactly we do the script for interfaces to go down and interfaces to come up.is this included in the TCL file or just those two comamnds take care of everything?Do the file attached in previous post has the real interfaces defined there??

Any recommanded guide for this kind of configuration...

Joe Clarke Thu, 10/29/2009 - 00:22

The Tcl policy will take care of watching the interfaces, and doing the shutdown and no shutdown. Yes, you must take that script, and upload it to your switch. You must also configure the environment variables as I have indicated. The script will look for those variables to know on what interfaces it will operate.

sameermunj Thu, 10/29/2009 - 01:30


Thanks for the reply.i will check the same.

==does those enviornmental variable will take care of reverse scenario also ??? i mean when my uplink will go down ideally both the uplink from down should go down.so i need to add 2 more statements or those 4 statements will take care of both scenarios.

last question is this setup is presently

working so do you suggest me to add the scripts as will as those variables in live scenario or during any maintainance window??will the script take care immediately or it will require any reboot.

Thanks in advance.

Joe Clarke Thu, 10/29/2009 - 07:19

Yes, the Tcl policy will bring the uplink back up when at least one of the distribution links comes back up.

The policy will take effect immediately. There will be no downtime. However, if you're worried about affecting production, then I strongly recommend you try this out in a lab first.

sameermunj Thu, 10/29/2009 - 08:39


All this we were doing for the 2 downlinks going down so that uplink will go down...

my query was if the Uplink goes down during normal case whats the remedy to make both downlinks down because this is also a failure scenario in which case firwall2 will transfer data to core 2 and core2 has to take it down.

for this do i need to mention 2 more enviornmental variable and add 1 more Tcl policy or same policy will work with 2 more enviornmental variables or no more change at all required.

with this my problem will get completely resolved

please suggest.

sameermunj Thu, 10/29/2009 - 22:50

Thanks for teh help.

hope this will resolve my issue completely.will check the same during next possible maintainance window and let u know the result.

just for my info==so changed the policy for this particular requirement right ??


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