Specifications

Chapter 9 IOS® Software and Network Management
9-7
Cisco IOS® Software
Milestones in the Life of a Train
The following table briefly describes the train lifecycle milestones
Cisco IOS Releases
A release is a snapshot in time of the code base of a train. Types of Releases include
Maintenance releases, Rebuild releases, General Deployment (GD) releases, and Special
releases.
Special Release Technology Identifiers
Lifecycle of Special Releases
Cisco’s end of life (EoL) policy is not applicable to special releases
Milestone Available through Sales
Channels
Bug Fixes TAC Support Download from
Cisco.com
FCS
Yes Yes
1
1. FCS corresponds to the first maintenance release on the train. Each new release receives regular maintenance during
the early part of the life cycle.
Yes Yes
EoS
No Yes Yes Yes
EoE
No No Yes Yes
EoL
No No No No
Release Description
Maintenance Releases
A maintenance release is a scheduled revision of Cisco IOS Software that introduces new features or bug fixes,
or both. Maintenance releases typically occur every eight to thirteen weeks, depending on the train.
Rebuild Releases
Circumstances and business demands may require that a number of images from a Cisco IOS train be rebuilt and
posted prior to the next planned maintenance release. Rebuilds are a Cisco IOS vehicle that delivers fixes on an
accelerated schedule.
General Deployment (GD)
Releases
A Cisco IOS Software release reaches GD certification when its quality has been demonstrated by extensive
deployment in diverse networks over extended periods of time; Cisco IOS releases achieve GD status after
meeting strict standards
General Deployment (GD)
Release Criteria
A GD release must meet the following criteria:
• Improving Trend in Defect Backlog
– Customer Advocacy (CA) evaluation of known defects
– No new features or platforms, defect resolution commits only
– No open Critical Account Program (CAP) issues
– Defect density measurements
– Software Reliability Engineering (SRE) projected defects
– Minimal code changes No serious defects in previous maintenance releases
• Customer Success
– Extensive customer exposure
– High level of customer satisfaction
• Cisco Deployment
– Comprehensive system test and deployment in Cisco's internal network
• Documentation
– Release Notes Enclosures (RNEs) complete
General Deployment (GD)
Lifecycle
After a release attains GD status, every subsequent revision of the release is also GD. Consequently, when a
release is declared GD, it enters a restricted maintenance phase. While in this phase, modification of the code,
including bug fixes, is strictly limited and controlled by a program manager to prevent bugs from being introduced
into the release.
Special Releases
A special release is a branch from a train code base that is introduced to quickly meet market demands for new
features or additional platform support. The early field adoption of new features and platforms that Cisco
introduces in special releases benefits customers who need to run new network equipment or services. The
following table lists technology identifiers used in the names of special releases.
Identifier Target Technology or Platform
X
Varies, one time release
Y
Z
A
Aggregation/Access Server/Dial
D
xDSL
H
SDH/SONET
J
Aironet Wireless Networking
M
Mobile Wireless
W
ATM/LAN Switching/Layer 3 Switching