Cisco IOS Naming Convention T 12.0 to M 15.0

Cisco IOS Naming Convention T 12.0 to M 15.0

This chapter will give you a brief introduction about Cisco IOS Naming Convention. Cisco IOS (initial Internetwork Operating System) is software that is used in most Cisco routers and switches. IOS is a package of routing, switching, security and other internetworking technologies integrated in a single multitasking operating system. The Cisco IOS portfolio supports a wide range of technologies and features. Clients choose an IOS based on a group of protocols and features supported by a particular image. Understanding the Cisco IOS feature set portfolio is useful in selecting the right IOS to meet the needs of an organization. Cisco made significant changes to the IOS software packages and licenses by making the transition from IOS 12.4 to 15.0 .

Cisco IOS Software Release Families and Trains

Cisco IOS software evolved from a single platform operating system for routing to a sophisticated operating system that supports a broad array of features and technologies, such as VoIP, NetFlow and IPsec . To better meet the requirements of the different market segments, the software is organized into families of software versions and software streams. A family of software versions consists of several versions of the IOS software that have the following characteristics:

• They share a code base.
• They apply to related hardware platforms.
• They overlap in compatibility coverage (when the life of an OS ends, another OS is introduced and supported).

Examples of Cisco IOS software versions, within a family of software versions, are 12.3, 12.4, 15.0 and 15.1 .
Along with each version of the software, there are new versions of the software created to implement bug fixes and new features. In IOS, these versions are called " trains ."
A Cisco IOS train is used to release versions with a common code base to a specific set of platforms and features. A train can contain several versions , and each version is a snapshot of the train code base at the time of launch. Because different families of software versions can be applied to various platforms or market segments, several trains can be in effect at any time.

Cisco IOS 12.4 Mainline and T Trains

The illustration shows the migration of software version 12.3 to 12.4. Within a family of software versions, there may be one or two closely related active trains.

The relationships between the version of the mainline train 12.4 and the 12.4T train of the Cisco IOS software are shown.
For example, the Cisco 12.4 IOS software family has two trains, 12.4T trains and 12.4 mainline trains.

Cisco IOS 12.4 TRAINS 

The Cisco 12.4 IOS software train is considered the mainline train. The mainline train receives mostly software corrections (errors) in order to improve its quality. The mainline train versions are also called " Maintenance Implementation (MD) versions ."
A mainline train is always associated with a technology train (T train). A T train, such as 12.4T, receives the same software bug fixes as the mainline train. The T train also receives new hardware and software compatibility features. The versions on the 12.4T train of Cisco IOS software are considered Early Deployment (ED) versions .
There may be other trains, depending on the family of the software version. For example, another available train is the service provider (train S) . An S train contains specific features designed to meet the requirements of service providers. All secondary trains on the mainline train (T, S, etc.) usually have an uppercase letter that designates the type of train.
Main Line Train = 12.4
T train: 12.4T 
(12.4 + new hardware and software compatibility features)
Until the family of version 12.4 of Cisco IOS software inclusive, the mainline trains and the T trains were separated.
In other words, from the mainline train, a T train branched out and became an independent code base that received new features and hardware compatibility. Over time, a new mainline train evolved from an established T train, and the cycle began again.
The use of several trains was modified with version 15 of the Cisco IOS software.

Cisco IOS 12.4 Mainline and T Numbering

The Cisco IOS version numbering convention is used to identify the version of the IOS software, including bug fixes and new software features. In the illustration, an example of the numbering scheme for the main line trains and for the T trains is shown:

• The software version numbering scheme for a mainline train consists of a train number, a maintenance identifier and a collection identifier.

For example, version 12.4 (21a) of Cisco IOS software is a mainline train. The version for a train T consists of a train number, a maintenance identifier, a train identifier and a collection identifier. For example, version 12.4 (20) T1 of Cisco IOS software belongs to train 12.4T of Cisco IOS software.

• Each maintenance identifier of the Cisco IOS 12.4 main line of software, such as 12.4 (7), includes additional maintenance and software fixes. This change is indicated by the number in parentheses.

Each maintenance release of Cisco 12.4T IOS software, such as 12.4 (20) T, includes these same software fixes, along with additional software features and hardware compatibility.

• Cisco uses collections of an individual version to integrate corrections of important problems. A collection typically includes corrections for a limited number of software defects, known as warnings. It is indicated with a lowercase letter inside the parenthesis of the mainline trains or with a final number on other trains.

For example, version 12.4 (21) of Cisco IOS software received some warning fixes, and the resulting collection was named 12.4 (21a). Similarly, 12.4 (15) T8 is the eighth collection of 12.4 (15) T

SINGLE VERSION NUMBERS

A unique set of individual version numbers is used for all trains 12.4 of the Cisco IOS software. Maintenance version 12.4 and version 12.4T use a pool of individual version numbers that are shared throughout the family of version 12.4 of that software. Version 12.4 (6) T of the Cisco IOS software was followed by version 12.4 (7) T and version 12.4 (8) T. This allows the administrator to track changes made to the code.

CISCO IOS SYSTEM IMAGE PACKAGES 12.4

Prior to version 15.0 of Cisco IOS software, that software had eight packages for Cisco routers, as shown in the illustration.

The package scheme was introduced with the mainline train 12.3 of the Cisco IOS software, and was subsequently used on other trains. Image packages consist of eight IOS images, three of which are considered higher packages.
The five non-superior packages are as follows:

1. IP Base : is the basic image of Cisco IOS software.
2. Voice over IP : converging voice and data, VoIP, VoFR and IP telephony.
3. Advanced Security : VPN and security features, including Cisco IOS firewall, IDS / IPS, IPsec, 3DES and VPN.
4. Service provider services (SP) : Add SSH / SSL, ATM, VoATM and MPLS to Voice over IP.
5. Base for companies : protocols for companies (Appletalk, IPX and IBM Support).

Three other superior packages offer additional combinations of IOS software features that address more complex network requirements.
All features are merged into the Advanced Enterprise Services package. This package integrates support for all routing protocols with Voice, Security and VPN capabilities:

• Advanced Enterprise Services : complete feature set of Cisco IOS software
• Enterprise Services : base for business and service provider services
• Advanced IP Services : advanced security, service provider services and IPv6 support

CISCO 15.0 IOS M AND T TRAINS

After Cisco IOS version 12.4 (24) T, the next version of Cisco IOS software was 15.0.
IOS 15.0 provides several improvements to the operating system, for example:

• New hardware and feature compatibility
• Greater consistency of features with other major versions of IOS
• Version of new features and more predictable collection programs
• Compatibility policies for proactive individual versions
• Simplified Version Numbering
• Clearer migration and software implementation guidelines

As shown in the illustration, Cisco IOS 15.0 uses a different version model of traditional 12.4 independent T and mainline trains.

Instead of being divided into independent trains, the T 15 and mainline trains of the Cisco 15 IOS software will have extended maintenance version (EM version) and standard maintenance version (T version) . With the new IOS version model, the mainline versions of the Cisco 15 IOS are called " M trains ."
Starting with 15.0, new versions in the form of a T train are available approximately two to three times per year. EM versions are available approximately every 16 to 20 months . The T versions allow you to receive the Cisco feature more quickly, before the next EM version is available.
An EM version incorporates the feature and hardware compatibility of all previous T versions. This makes the latest versions of EM contain the total functionality of the train at the time of launch.

CISCO IOS TRAIN NUMBERING 15

The version numbering convention for IOS 15 allows you to identify the specific IOS version, including bug fixes and new software features, similar to families of previous IOS versions. The illustration shows examples of this convention for the EM version and the T version.

EXTENDED MAINTENANCE VERSION

The EM version is ideal for long-term maintenance , and allows customers to meet the requirements, implement the version and maintain it for an extended period. The mainline train incorporates features provided in previous versions and further improvements to incremental features and hardware compatibility.
The first maintenance collection (for bug fixes only, without new features or new hardware compatibility) of version 15.0 (1) M bears the number 15.0 (1) M1. Subsequent maintenance versions are defined by an increase in the maintenance collection number (e.g., M2, M3, etc.).

STANDARD MAINTENANCE VERSION

The T version is used for short deployment versions ideal for the latest features and hardware compatibility before the next version of EM is available. Version T provides regular error correction maintenance collections and critical error support for errors affecting the network, such as Product Security Incident Reporting Equipment (PSIRT) problems.
The first version of new features 15 T planned carries the version number 15.1 (1) T. The first maintenance collection (for bug fixes only, without new features or new hardware compatibility) of version 15.1 (1) T will bear the number 15.1 (1) T1. Later versions are defined by an increase in the maintenance collection number (e.g., T2, T3, etc.).

 IOS 15 SYSTEM IMAGE PACKAGES

The Cisco second generation integrated service router series (ISR G2) 1900, 2900 and 3900 support services on demand through the use of software licenses.
The Services on demand process allows customers to achieve operational savings through ease of ordering and software management. When an order for a new Cisco G2 ISR platform is placed, the router ships with a unique and universal image of Cisco IOS software, and a license is used to enable specific feature set packages, as shown in Image:

There are two types of universal images supported in ISR G2:

• Universal images with the designation “universalk9” in the name of the image : this universal image offers all the features of Cisco IOS software, including secure content cryptography features, such as IPsec VPN, SSL VPN and secure unified communications.
• Universal images with the designation “universalk9_npe” in the name of the image : secure compliance with the encryption capabilities provided by Cisco Software Activation meets the requirements for exporting encryption capabilities.

Some countries have import requirements that require that the platform does not support any secure cryptography functionality, such as content cryptography.
With the ISR G2 devices, the selection of the IOS image was facilitated, because all the features within the universal image are included. The features are activated by licenses (product activation key - PAK). Each device ships with universal image.
Figure shows the suggested migration for the next generation ISRs from IOS 12 (IOS reform packages) to IOS 15 (simplified packages).

IOS IMAGE FILE NAMES

The Cisco IOS image file is based on a special naming convention. The name of the Cisco IOS image file contains several parts, each with a specific meaning. It is important to understand this naming convention when updating and selecting a Cisco IOS software.
As shown in Image 8, the show flash command shows files stored in flash memory, including system image files.

IMAGE NAME FOR IOS 12.4

In Image, an example of an image name of the IOS 12.4 software is shown.

• Image name (c2800nm) : Identifies the platform on which the image is executed. In this example, the platform is a Cisco 2800 router with a network module.
• advipservicesk9 : Specify the feature set. In this example, advipservicesk9 refers to the Advanced IP Services feature set, which includes the service provider and advanced security packages along with IPv6.
• mz : indicates where the image is executed and if the file is compressed. In this example, "mz" indicates that the file runs from RAM and is compressed.
• 124-6.T : indicates the format of the file name for image 12.4 (6) T. This is the train number, the maintenance version number and the train identifier.
• bin : the file extension. This extension indicates that this is an executable binary file.

IMAGE NAME FOR IOS 15

In following Image, the different parts of an IOS 15 system image file in an ISR G2 device are illustrated:

• Image name (c1900) : Identifies the platform on which the image is executed. In this example, the platform is a Cisco 1900 router.
• universalk9 : specifies the designation of the image. The two designations for an ISR G2 are universalk9 and universalk9_npe. Universalk9_npe does not contain secure encryption and is intended for countries with encryption restrictions. Features are controlled by licenses and can be divided into four technology packages: IP Base, Security, Unified Communications and Data.
• mz : indicates where the image is executed and if the file is compressed. In this example, "mz" indicates that the file runs from RAM and is compressed.
• SPA : indicates that the file is digitally signed by Cisco.
• 152-4.M3 : Specifies the format of the file name for image 15.2 (4) M3. This is the IOS version, which includes the numbers of the main version, the secondary version, the maintenance version and the maintenance collection. The M indicates that it is an extended maintenance version.
• bin : the file extension. This extension indicates that this is an executable binary file.

MEMORY LOCATION AND COMPRESSION FORMAT

The most common designation for memory location and compression format is mz . The first letter indicates the location where the image is executed on the router. The locations may include the following:

• f : flash
• m : RAM
• r : ROM
• l : relocatable

The compression format can be z for zip or x for mzip. File compression is a method that Cisco uses to compress some images executed from RAM that is effective in reducing image size. It decompresses itself, so that when the image is loaded into RAM to run, the first action is decompression.

MEMORY REQUIREMENTS

On most Cisco routers, even on integrated service routers, the IOS is stored in CompactFlash memory as a compressed image and loaded into the DRAM during startup.
The Cisco IOS software version 15.0 images available for Cisco 1900 and 2900 ISRs require 256 MB of flash memory and 512 MB of RAM. The ISR 3900 requires 256 MB of flash memory and 1 GB of RAM. This does not include additional management tools, such as Cisco Configuration Professional (Cisco CP). For complete details, see the product data sheet for the specific router.