The Versatile Interface Processor 4 (VIP4) for Cisco 7500 Series routers is supported in several Cisco IOS® software releases. This document provides a guide to the various releases, and specifically discusses migration paths for current Cisco 7500 installations adopting the VIP4.
At First Customer Shipment (FCS), the VIP4 is supported in the Release 12.1, 12.1E, 12.1T, and 12.0S. It is helpful to understand how the releases were derived to understand the maturity and feature sets offered by each release.
The last 12.0T release was 12.0(7)T, after which the release numbering was incrementedthe next maintenance release of this code is called 12.1(1). Release 12.1(1) and subsequent 12.1 releases are focused on code maturity and stability, and they are intended to achieve general -deployment (GD) certification. To reach this goal, the feature set of Release 12.1 was frozen with Release 12.1(1); new features and hardware support are now directed into the 12.1E and 12.1T releases.
When Release 12.0T became Release 12.1, two new branches, called 12.1E and 12.1T, were created for new feature integration. Release 12.1T integrates features and hardware support for platforms across the Cisco product line, whereas Release 12.1E is focused exclusively on feature and hardware support for the Cisco 7500, 7200, and 7100, and Catalyst® 6000 families. Both the 12.1E and 12.1T branches are "synchronized" to 12.1, receiving the same bug fixes committed into the 12.1 branch.
Figure 1 Cisco IOS Release Relationships
The last 12.1T release was 12.1(5)T, after which the release numbering was again incrementedthe next maintenance release of this code is called 12.2(1). Simlar to that of Release 12.1, Release 12.2(1) and subsequent 12.2 releases are also focused on code maturity and stability because they are intended to achieve general -deployment (GD) certification. To reach this goal, the feature set of Release 12.2 was frozen with Release 12.2(1).
When Release 12.1T became Release 12.2, three new branches, called 12.2S, 12.2B, and 12.2T, were created for new feature integration. Release 12.2T integrates features and hardware support for platforms across the Cisco product line. Release 12.2S is focused exclusively on feature and hardware support for the Cisco 7600, 7500, 7400, 7200, and 7100, and Catalyst® 6000 product families, and Release 12.2B is primarily focused on Broadband solutions, supporting the Cisco 7400, 7200, and 6400 product families.
For most VIP4 customers, Release 12.1 is the suggested release. It offers all the features of the extensively deployed 12.0T release, and is the GD-certified release on the Cisco 7500 platform. Release 12.1 also offers a rich variety of software feature sets, including IP, multiprotocol, and special feature sets such as IP Security (IPSec) encryption and the Cisco IOS Firewall Feature Set. Where additional features are required, Releases 12.1E or 12.2 should be considered. Note that IPSec and Firewall features are supported on the RSP and VIP4 can coexist with these features.
Release 12.0S supports all 12.0 features as well as additional service-provider features; it is suitable for service-provider applications as well as large enterprises. However, Release 12.0S does not offer the extensive feature sets of Release 12.1, and is strictly for IP deployments.
Table 1 VIP4 Software Release Summary
Table 2 Cisco IOS Software Migration Paths
|Previous Release||Suggested Migration Paths||Comments|
Cisco IOS Releases 12.1, 12.1E, and 12.1T require a minimum of 64 MB of Route Switch Processor (RSP) memory and 64 MB of VIP4 program memory. Some configurations will require more. For example, in service-provider applications, 128 MB of VIP4 program memory is required, with 256 MB recommended.
Before deploying a Cisco IOS software release in a production network, always consult appropriate product-specific documentation, release notes, and field notices, refer to the online defect tracking system, and perform acceptance testing in your own test environment.
Before deploying a Cisco IOS software release, always refer to its release notes to confirm all appropriate features, interfaces, and platforms are supported, and to understand any caveats with a particular maintenance release. Often, a particular maintenance release (or later) may be required for your application, as indicated by the release notes.