Exploring EEM/TCL Capabilities

[Robert Arellano]

Hello,

I am extremely fascinated and intrigued with EEM scripting and exploring the capabilities.

Before I dive in completely and start investing time into this possible solution, I'm curious to find out if what I'm trying to achieve is possible through EEM and/or TCL scripting.

Problem:

We have remote sites that use cellular connections back to our core. Some have poor and intermittent coverage which causes connectivity issues. Sometimes when we're able to get someone on site to troubleshoot we find that the cellular cards are connecting to invalid or unusable PLMN's (PLMN Selection is Auto in most cases.) Sometimes to restore connectivity we have to manually select a different PLMN.

Hopeful solution:

My hope is to use EEM and/or TCL scripting to automate the manual plmn search and selection. Essentially, I want to tell the router to perform a PLMN search, show the results and manually set the PLMN depending on the output of the PLMN search and potentially repeating the manual selection to another available PLMN if connectivity doesn't restore.

Does this strike you as something we could accomplish? If you need/want more information or I am not clear in my explanation, please let me know and I'll do my best to supply that information. Below is some sample output I would be basing the solution on:

Remote_Router#cellular 0/1/0 gsm plmn search
Searching for available PLMNs...Please wait...
This may take up to 5 minutes.
Remote_Router#sh cellular 0/1/0 network
Current Service Status = Normal, Service Error = None
Current Service = Combined
Packet Service = EDGE (Attached)
Packet Session Status = Active
Current Roaming Status = Roaming
Network Selection Mode = Manual
Country = PER, Network = TEM
Mobile Country Code (MCC) = 716
Mobile Network Code (MNC) = 6
Location Area Code (LAC) = 5202
Routing Area Code (RAC) = 1
Cell ID =
Primary Scrambling Code = 0
PLMN Selection = Manual
Registered PLMN = MOVISTAR , Abbreviated = TEM
Service Provider =
Available PLMNs:
PLMN Name = PERN3 (NXT3)
MCC = 716, MNC = 17
Status = Supports GPRS, Network = GSM

PLMN Name = TIM PERU (TIM)
MCC = 716, MNC = 10
Status = Supports GPRS, Network = GSM

PLMN Name = MOVISTAR (TEM)
MCC = 716, MNC = 6
Status = Registered,Supports GPRS, Network = GSM

Again, I appreciate any and all assistance, advise, etc. on this venture.

[Joe Clarke]

EEM can absolutely help here.  You can have one applet that initiates the search, then configures another timer applet to wait five minutes, and then process the results.  Have a look at How To Introduce Large Delays In EEM Policies  on how you might do this.

First, decide what you want to do to trigger the initial policy.  Have that policy enter enable mode and perform the test.  Then, have it enter configure mode and install the nested timer policy as documented in the article above.  That policy would execute on a 300 second countdown.  When it executes, it will execute the "show cellular" command and parse the results to select the desired PLMN.

[Robert Arellano]

Thanks Joe, I am familiar with nesting the policies but based on my understanding and if I'm understanding your explanation, I would have to already know the available PLMNs and pre configure the command to select the desired PLMN? or could the policy use regular expression or something to change the command based on the output?

Thanks again!

[Joe Clarke]

I meant the latter: use regular expressions to find the pattern in the output you need in order to determine the optimum PLMN.