In preparation of your CCNA exam, we want to make sure we cover the various concepts that we could see on your Cisco CCNA exam. So to assist you, below we will discuss one of the more difficult CCNA concepts; how to recover from a deleted IOS on a Cisco 2900 or 3550 Switch. As you progress through your CCNA exam studies, I am sure with repetition you will find this topic becomes easier. So even though it may be a difficult concept and confusing at first, keep at it as no one said getting your Cisco certification would be easy!
- See Full List On Cisco.com
- Upgrading Software In Catalyst 2900XL And 3500XL Switches Using The Command Line Interface
- Cisco Catalyst 3550 Series Intelligent Ethernet Switches
- All Switches Products - Cisco
The Cisco IOS image used must be a k9(crypto) image in order to support SSH. Try to update to: c3550-ipbasek9-mz.122-52.SE.bin. Also consider this link: Configuring Secure Shell on Routers and Switches Running Cisco IOS - Cisco. Cisco delivers innovative software-defined networking, cloud, and security solutions to help transform your business, empowering an inclusive future for all.
During our Cisco CCNA certification studies, there will be many times we will make a mistake that we wish we did not. One of them will surely be deleting the IOS on a Cisco router or Cisco switch by mistake. Some times you do this during your Cisco CCNA studies when you are trying to do an IOS upgrade and it goes awry or sometimes just the slip of a keyboard click. In either situation, below we will cover the process for you to reload the Cisco IOS on a Cisco 2900 or 3550 switch using hyperterminal. We will assume you have read our document on how to connect to your switch via hyperteminal already and know how to do that.
So let’s also take this time to review a few commands for your Cisco CCNA studies. Connect via hyperterminal and boot the Cisco 3550 switch(this is also the same process for the Cisco 2900 series, so if you have a 2900 switch, just change the file name).
After you boot the switch, if your IOS is deleted you will end up at the following prompt:
switch:
So now time to review CCNA commands. Let’s verify that we actually deleted our IOS on the switch. Issue the following command which will display the contents of your switch’s flash:
switch: dir flash:
2 −rwx 556 Mar 01 1993 00:00:35 vlan.dat
4 −rwx 1595 Mar 01 1993 19:52:41 config.text
Ok, so we verified with our first new CCNA command that there is actually no IOS file in there. IOS files just in case you did not know usually have a .bin extension. We do se a config file and a vlan.dat file. But neither of them are IOS files. So time to practice our Cisco CCNA skills by reloading our Cisco IOS. Now I warn you, this will take a while.
Read this next part a couple of times to make sure you really understand what you are about to do. As you have to do this quite quickly or it will timeout. But being sure you are starting to master your Cisco CCNA concepts, you will pick it up with no problem at all. Worst case, if it times out, you can start over again as it is more practice preparing your for your Cisco CCNA exam!
On your Cisco 2900 or 3550 switch you will be at the following prompt: switch:
type in the following command(assuming this is the name of the Cisco IOS you have loaded on your computer that you are using hyperterminal from)
switch: copy xmodem: flash:c3550-ipservicesk9-mz.122-25.see.bin
In hyperterminal, it will start to say…..
Begin the Xmodem or Xmodem-1K transfer now…
CCCCCCCCCSSSSSSSSSSSS
As soon as you see that(quickly) go in the hyperterminal menu to:
Transfer
Send File
Browse(browse to the IOS filename)
(You should see the file c3550-ipservicesk9-mz.122-25.see.bin)
Double click the c3550-ipservicesk9-mz.122-25.see.bin file.
Click Send
You should see the file start to upload and transfer. Once it is complete, you should see a message similar to this:
File “xmodem:” successfully copied to “flash: c3550-ipservicesk9-mz.122-25.see.bin “
At that point, shut the switch off and turn it back on and see if it boots properly. Hopefully it did and then you have one more Cisco CCNA concept conquered on your way to achieving your Cisco CCNA certification!
I hope you found this article to be of use and it helps you prepare for your Cisco CCNA certification. I am sure you will quickly find out that hands-on real world experience is the best way to cement the CCNA concepts in your head to help you pass your CCNA exam!
Real World Application
This lab will help you will identify the Cisco Internetwork Operating System (Cisco IOS) Running on a Cisco Device. Knowing what Cisco IOS Version and Feature Set is running on your Cisco devices is crucial to planning and deploying required features. Think of Feature Sets as Windows Vista Distributions, you have Basic, Home Edition, Home Premium, Business, Ultimate and Enterprise. In Cisco IOS, we have similar distributions called “Feature Sets” that dictate which features will be available for you to configure. Each feature set have different prices. Some feature sets contain the same features as others; this will be discussed later in the lab.
Lab Prerequisites
- Complete Lab 1.2 before attempting this lab or have a current Cisco console session open to your Cisco device.
Lab Objectives
- Identify what IOS Version and Features Set your Cisco device is currently running.
Lab Instruction
There are several ways to identify which Cisco IOS your Cisco device is running. First way being to examine the boot dispatch, this will display the image name that is loaded from flash which in return can be used to identify the IOS Version and Feature Set of the image.
Provided below is an example of the required dispatch from the boot process which can be used to identify which IOS Version and Feature Sets the router is currently loading.
Turn your attention to line 2 where you see C3620-IK9O3S7-M; this displays the features that are included in the image and the loading type (which will be discussed later) for the image that is currently be loaded by the Router. Following the feature set being loaded you can also see the Version of the IOS. As shown in this example, the router is currently booting IOS Version 12.3(25)
The most common way of obtaining IOS identification information is by using the show version command. This command shows various information pertaining to the Cisco IOS Version and Feature Set as well as hardware information about the router.
The textbox below shows the dispatch of the show version command.
As you can see lines 2, 3 & 4 are identical to previously discussed boot dispatch information. However take look at line 13 and you’ll see System image file is “flash:c3620-ik9o3s7-mz.123-25.bin” This is the actual image file name that is currently running on the router. This image name is very helpful in identifying the IOS Version and Feature set.
Prior to Cisco IOS Version 12.4, Cisco had a very complex naming convention for their Feature Sets. This naming convention consisted of letters identifying certain features in the image.
Below is a chart comprised of common pre-standing naming convention identification letters;
| Image Letter | Feature Set |
|---|---|
| I | IP |
| Y | IP on 1700 Series Platforms |
| S | IP Plus |
| S6 | IP Plus – No ATM |
| S7 | IP Plus – No Voice |
| J | Enterprise |
| O | IOS Firewall/Intrusion Detection |
| K | Cryptorgaphy/IPSEC/SSH |
| K8 | 56Bit DES Encryption (Weak Cryptography) |
| K9 | 3DES/AES Encryption (Strong Cryptography) |
| X | H323 |
| G | Services Selection Gateway (SSG) |
| C | Remote Access Server or Packet Data Serving Node (PDSN) |
| B | Apple Talk |
| N | Novel IP/IPX |
| V | Vox |
| R | IBM |
| U | Unlawful Intercept |
| P | Service Provider |
| Telco | Telecommunications Feature Set |
| Boot | Boot Image (Used on high end routers/switches) |
Now let’s break down the naming convention of the image name for our previous image; flash:c3620-ik9o3s7-mz.123-25.bin;
Now let’s break down the Features included with this image as shown below;
i = IP
k9 = Strong Cryptography (3DES / AES)
o3 = IOS Firewall/Intrusion Detection
s7 = Plus (7 = No Voice)
Official Image Name: Cisco 3620 12.3(25) IP/FW/IDS PLUS 3DES IPSEC NO VOICE
Many images differ in how they load and their compression. As these features are also identified in the image name below, the following chart will identify execution types and compression formats.
| Image Letter | IOS Boot Location |
|---|---|
| f | The image executes from Flash memory. |
| m | The image executes from RAM. |
| r | The image executes from ROM |
| l | The image is relocatable. |
| z | The image is compressed using ZIP format. |
| x | The image is compressed using MZIP format. |
| w | The image is compressed using STAC format. |
The example 3620 image used in this lab executes from RAM and uses ZIP compression.
As of 2006, Cisco has introduced a new naming convention for feature sets. This new naming convention started in 12.3 and was implemented as the feature set naming standard in 12.4
Below is a feature tree comprised of the new naming convention used for Cisco router images 12.3T and greater;
You can see that IP Base is the basic image, from this image it branches off into IP Voice, Advanced Security or Enterprise Base.
IP Voice also has an upgrade to Service Provider Services, which includes SP Services Features, IP Voice Features and IP Base features.
See Full List On Cisco.com
Only “Advanced” Images contain Advanced Encryption Standard (AES) Cryptography
The following categories summarize the new naming convention:
| Feature Set | Description |
|---|---|
| Base | Entry level image (IP Base, Enterprise Base) |
| Services | addition of IP Telephony Service, MPLS, Voice over IP, Voice over Frame Relay and ATM (Included in SP Services, Enterprise Services) |
| Advanced | Addition of VPN, Cisco IOS Firewall, 3DES encryption, SSH, Cisco IOS IPSec and Intrusion Detection Systems (IDS) (Advanced Security, Advanced IP Services) |
| Enterprise | Addition of multi-protocols, including IBM, IPX, AppleTalk (Enterprise Base, Enterprise Services) |
Just like the new naming convention for Cisco Router IOS, Cisco has given the Switch IOS a new naming convention as well. This naming convention is very similar to the router IOS naming convention. Shown below is a feature tree of the new switch IOS naming convention;
Below are some examples of images using the new Cisco naming convention;
Example images for a Cisco 2800 Series Router:
c2800nm-adventerprisek9-mz.124-21.bin
c2800nm-ipbase-mz.124-21.bin
Example Images for a Cisco Catalyst 3750 Series Switch:
c3750-advipservicesk9-mz.122-44.SE.bin
c3750-ipservicesk9-mz.122-44.SE.bin
c3750-ipbase-mz.122-44.SE.bin
IP Base; formally known as Standard Multilayer Image (SMI) on Cisco Catalyst 3550 Series switches includes advanced quality of service, rate limiting, access control lists (ACL’s) and basic static and RIP routing functionality.
Upgrading Software In Catalyst 2900XL And 3500XL Switches Using The Command Line Interface
IP Services; formally known as Enhanced Multilayer Image (EMI) on Cisco Catalyst 3550 Series Switches has a more feature rich set of enterprise-class routing functionality as well as advanced hardware-based IP Unicast and IP Multicast routing, policy based routing (PBR).
Advanced IP Services is not available as a pre-installed license but is available as an upgrade license. This feature set includes IPv6 routing and IPv6 ACL support.
Enterprise Services & Advanced Enterprise Services are the cream of the crop. The images includes all features available to the platform; also these license(s) are the most expensive. These license(s) are only supported on various modular switches such as the Catalyst 4500, 4900, 6500 and others.
Below are a few examples of switch models you can purchase and the software license that’s bundled with the platform(s).
C3560-24PS-S = Cisco 3560 Series 24 Ports PoE with Standard Image (IP Base)
C3750-48TS-E = Cisco 3750 Series 48 Port Non-PoE with Enhanced Image (IP Services)
The Cisco Catalyst 2960 Series has a different license model due to the switch being strictly layer 2. The Catalyst 2960 Series license model is similar to the Catalyst 2950 Series which includes two separate feature sets, Standard Image and Enhanced Image however, the new feature sets are called LAN LITE & LAN BASE. These new feature sets do have a significant difference including Quality of Services (QoS), Gigabit Ethernet Support, RPS, Rapid Spanning Tree, Link State Tracking, 802.1x enhancements, DHCP Snooping and many more features which can be found on the Cisco website.
Cisco Catalyst 3550 Series Intelligent Ethernet Switches
Cisco IOS 15.0 was released October 1st 2009 and with this new mainline IOS release, we’ll see the use of the Universal Image. The feature sets have not changed but now with the use of these new universal images, image feature sets have to be licensed using a license file stored in NVRAM. Upon boot, the IOS looks at this license file and activates the features specified in the license; that of which you’ve purchased.
Each license file is specific to each platform serial number so therefore license files will not be swappable. No doubt with all the Cisco IOS piracy that occurs in the Cisco networking world today, Cisco systems is losing millions if not billions in license profit.
The next generation Integrated Services Routers which include the 1900 Series, 2900 Series and 3900 Series will use a single universal image file and require feature sets to be licensed. As part of the license management suite, Cisco offers a license management server as well as an IOS feature that can automatically download the license file from Cisco if your router is able to access the internet.
All Switches Products - Cisco
Cisco also utilized this technology with the 3560E and 3750E Switches. Example IOS IMAGE names shown below;
c3560e-universalk9-mz.122-50.SE2.bin
c3750e-universalk9-mz.122-50.SE2.bin
c3900-universalk9-mz.150-1M.bin
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