How to select a Cisco IOS software version

This article mainly introduces IOS naming rules and feature sets, and also introduces IOS reference version evaluation. I believe you have read this article and have a detailed understanding of the IOS software version..

IOS naming rules and feature set

Cisco IOS software image file names have naming rules to help customers identify the feature set of the image file.

The Cisco IOS file name, such as the c7200-ajs40-mz, consists of three main parts:

* Hardware platform

* Feature set

* Memory features

Hardware Platform

In the c7200-ajs40-mz C7200 represents the software applicable hardware platform, such as C7200 represents Cisco7200 series router, RSP represents Cisco7500 router, while GSR represents Cisco high-end products Gigabit exchange router.

Feature set

Cisco IOS software can be a combination of different feature sets. For example, ajs40 in ASN represents the APPN feature set, enterprise feature set, NAT feature set, and 40-bit encryption feature set. Cisco also defines over 30 different feature set codes, including:

A APPN feature set Boot Image d Desktop feature set

G ISDN feature set I IP feature set l enterprise feature set

N IPX feature set o firewall feature set p operator feature set

R IBM feature set v VIP and dual RSP support x X.25/FR/H.323

Memory features

Early Cisco low-end devices, such as IOS 2500 series, were not running in memory but in Flash cards. Therefore, this feature is specified in the IOS file name, for example, m in the c7200-ajs40-mz represents running in the Memory RAM), if f Represents running in the Flash card, if it is r, it indicates running in ROM.

In the file name, z indicates that the image file is compressed in ZIP format, x indicates MZIP compression, or w indicates Stac compression.

IOS version Evaluation Reference

When to upgrade the version

For the production network in use, upgrading the software of the network device poses a certain risk. Although new software versions can bring more new features, they often bring more software bugs or even unexpected errors. Therefore, we recommend that you upgrade and replace the software version that has been proven to be stable only in the following situations:

* The current software version does not support some new services to be launched, such as Voice, Video, or QoS.

* The current software version does not support some hardware platforms or boards to be updated.

* The current software version is about to enter the service stop period EOE)

* The current software version has obvious security vulnerabilities or has been proved to have some fatal defects.

General recommendations

Multiple considerations are required to select an appropriate version. Different network applications and customer needs should be differentiated. However, there are still some general suggestions that apply in most cases:

* Whenever possible, select the GD version released by Cisco.

* Try to avoid selecting the latest version.

* Try to avoid selecting versions with a large number of unnecessary functions and features

* Try to avoid selecting the version that is about to expire.

* Make full use of the online tools and reference documents provided by Cisco to evaluate the features of the upgraded version to determine customer needs

When selecting the IOS version, the first thing that needs to be done is to clarify the purpose of the upgrade and the customer's needs. For new features or new features

To upgrade the hardware, you need to know the following requirements:

Platform requirements: network devices are Cisco products, and the hardware boards to be supported are added.

Protocol requirements: What protocols are required for network applications, such as TCP/IP, IPX, Or ISIS routing protocols

Feature requirements: some special features required by the vro, such as NAT and HSRP

Stability requirements: whether the network carries critical services and whether there are high requirements for stability and reliability. To address these requirements, Cisco provides a wide range of tool sets on CCOCisco Connection Online.