5 things Cisco Packet Tracer WONT teach you (but you should know).


In this post I am going to have a bit of a moan about some of the things that the Cisco Packet Tracer (PT) does not support. I am sure that this post is just the tip of the iceberg!

I have not touched PT since my CCNA days, but now, several years on, I am going back to it to have a look. This is more of a fact finding mission, expect updates as I play with it a bit more.

The version I am using is 6.3.0.0009:


So, interface-wise, nothing seems to have changed that much since I used it last time. The layout is still the same, its all very drag and drop. We have a couple of different device options, such as the 1841 and 1941 routers, the 3560 switch and the ASA, which brings us to our first problem:

1: Packet Tracer does not support new IOSes

The versions on here are OLD!
Switch   Ports  Model              SW Version              SW Image
------   -----  -----              ----------              ----------
*    1   26     WS-C3560-24PS      12.2(37)SE1             C3560-ADVIPSERVICESK

ciscoasa#sh ver

Cisco Adaptive Security Appliance Software Version 8.4(2)
Device Manager Version 6.4(5)

Router(config-if)#do sh ver
Cisco IOS Software, C1900 Software (C1900-UNIVERSALK9-M), Version 15.1(4)M4,
You do not have the option to add new versions to PT. It's very limiting! You can't run Qemu nodes, and the ASA is very out-dated (and it's a 5505 which are right the the bottom end of the scale).

Anyway, how do we know what versions we are running? Well, you would usually look at the version (show version), but if you just want to get the information, and not the waffle, you would use the pipe command to include just the version, which brings us onto point #2.

2: No piping commands!

The really sucks, you can't use the pipe command to get just the information you need!
Switch(config)#do sh ver | i Version
sh ver | i Version
       ^
% Invalid input detected at '^' marker.
 
Switch(config)#
I want to be able to truncate the information I get to just the stuff I need, like finding the configuration for a particular interface.

3: You can't sh run interface

You have to look through the entire configuration to find the details for a particular interface:
Switch#sh run int fa0/24
              ^
% Invalid input detected at '^' marker.
 
Switch#sh run ?
  <cr>
Switch#sh run interface fa0/24
              ^
% Invalid input detected at '^' marker.
 
Switch#sh run ?
  <cr>
Switch#sh run 
Keep pressing that space bar to continue! This is not an efficient use of your time, and certainly as you progress from CCNA into a network career, and start looking towards the CCNP and CCIE, you will need to now how to get to the information you need as quickly as possible! You can't spend your time searching through the configuration to find the information you need.

Let's press on a look for something a little more advanced in the switching and routing domains.

4: MST

Switch(config)#spanning-tree mode ?
  pvst        Per-Vlan spanning tree mode
  rapid-pvst  Per-Vlan rapid spanning tree mode
Switch(config)#spanning-tree mode
No Multiple Spanning-Tree. I suppose this is OK, because it's not on the CCNA. But External BGP made it into the new v3.0, so how well is BGP supported?

5: No Internal BGP (iBGP)

Router(config-if)#ip add 1.1.1.1 255.255.255.255
Router(config-if)#router bgp 10
Router(config-router)#bgp router-id 1.1.1.1
Router(config-router)#neighbor 2.2.2.2 remote-as 10
Router(config-router)#
%Packet Tracer does not support internal BGP in this version. Only external neighbors are supported.


Router(config-router)#
Seriously? Oh, come on! How hard is it to have internal BGP working as well as external BGP? That's just plain lazy!

I am sure that there are many more commands that re not supported, but this was just a quick test.

Considering PT is supposed to be the platform that engineers start with, it's not teaching you how to be an effective engineer.

There will be occasions when time is not on your side, be it when you are troubleshooting an issue, or when you are taking an exam. You need to learn the little tricks that will make your life as a network engineer easier and more efficient. Packet Tracer will limit you as an engineer. This is why I moved away from it years ago, it certainly won't help you as you progress in your studies. This is why platforms such as UNetLab and GNS3 are so popular. They support the full set of commands, allowing you to become an excellent network engineer, rather than a mediocre one.

When I started writing CCNA and Beyond, I made the decision to aim higher than PT would allow, and you should aim higher as well. Don't be limited by Packet Tracer, aim higher and use a proper platform for your studies.

Packet Tracer will not make you a good engineer, you won't learn the little tricks good engineers use to make their life easier and more effective. Achieving your potential is all about not being limited, Packet Tracer will limit you. You may not see it at the moment, but as you progress, you will start to see this.



CCIE #49337, author of CCNA and Beyond, BGP for Cisco Networks, MPLS for Cisco Networks, VPNs and NAT for Cisco Networks.

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2 comments

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May 28, 2016 at 11:58 AM delete

Hi Stuart,
From what I understand, they take the exact features that are needed to complete the CCNA Blueprint and put that in packet tracer, nothing more and nothing less. That is why it is so limited. If you want to study the exact commands that you need for CCNA, then its fine but that is not advice I would give to anybody trying to be a Network Engineer "Study the exact minimum you need to pass the CCNA".

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May 29, 2016 at 3:35 AM delete

I absolutely agree. Learning networking is not just about studying for an exam, it's the start of a career. You will be expected to support a lot of different technology, so learning the minimum will set you back. All the technologies are inter-linked as well, so widening the knowledge will help to solidify the knowledge in the areas tested in the exams.

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