Last updated: July, 2010
General
• Predictable new feature release (approximately 3 times a year) and maintenance rebuild schedules
• Broadened operational consistency for features
• Proactive support policies
• Enhanced release numbering
• Clearer software deployment and migration guidelines.
Key highlights of Release 15M&T, illustrated in Figure 1 below, include the following:
• Approximately 3 new feature releases per year.
• 15 M (Extended Maintenance) releases delivered on a more frequent basis (approximately every 16 months), enabling customers to qualify, deploy, and remain on a release longer with active support.
• 15 T (Standard Maintenance) releases (in between 15 M releases) ideal for the very latest features and hardware support before the next 15 M release becomes available.
• Rebuilds of 15M&T releases for bug fixes and ongoing software maintenance (no new features delivered in rebuilds).
• Release 15.0(1)M (FCS November, 2009) is the first 15 M release.
• Release 15.1(1)T (FCS March, 2010) is the first 15 T release.
Note: AppleTalk Phase I and II, and Service Selection Gateway (SSG) feature are not supported in Release 15M&T. Refer to the following bulletins for more information:
AppleTalk Support Discontinuation: http://www.cisco.com/en/US/prod/collateral/iosswrel/ps8802/ps5460/product_bulletin_c25-520459.html
SSG Support Discontinuation: http://www.cisco.com/en/US/prod/collateral/routers/ps341/end_of_life_notice_c51-501483.html
Figure 1. Release 15M&T Overview

• Drive business productivity with Cisco IOS innovations in security, voice, manageability, IP services, and rich media-enabled capabilities architected and designed to deliver a more consistent user experience and improved operational efficiency.
• Simplify feature selection through easier software management designed to enable faster deployment of enhanced borderless network services.
• Support remote branch offices and teleworkers who depend on secure Internet access and corporate network connectivity.
• http://www.cisco.com/en/US/products/sw/iosswrel/ps5460/prod_bulletins_list.html
• http://www.cisco.com/en/US/products/index.html
• http://www.cisco.com/cisco/web/support/index.html
To determine which features are supported in a specific release visit Cisco Feature Navigator http://www.cisco.com/go/fn.
Types of Cisco IOS Software 15M&T Releases
Release 15 M (Extended Maintenance)
• Ideal for long-term maintenance, enabling customers to qualify, deploy, and remain on the release for an extended period.
• Provides approximately 40 months of total support.
• Incorporates features delivered in previous releases plus incremental new feature enhancements and hardware support.
Release 15 T (Standard Maintenance)
• Short deployment releases ideal for latest new features and hardware support before the next extended maintenance 15 M release becomes available.
• Provides 19 months of support.
• Incorporates features and hardware support delivered in previous releases.
Figure 2. Release 15 M numbering. The letter M after the parenthesis denotes Extended Maintenance release.

Figure 3. Release 15 T numbering. The letter T after the parenthesis denotes Standard Maintenance release.

Figure 4. Maintenance rebuild methodology for Release 15M&T:

• Release 15.0(1)M includes incremental new software features and hardware support, features previously delivered in Release 12.4T, and software fixes
• After its initial introduction, Release 15.0(1)M will receive ongoing maintenance (bug fixes) through release rebuilds
• Rebuilds are identified by a release number suffix increment:
The 1st maintenance rebuild of Release 15.0(1)M is numbered 15.0(1)M1
The 2nd maintenance rebuild of Release 15.0(1)M is numbered 15.0(1)M2
The 1st maintenance rebuild of Release 15.1(1)T is numbered 15.1(1)T1
The 2nd maintenance rebuild of Release 15.1(1)T is numbered 15.1(1)T2
Cisco IOS Software Release 15.0(1)M
Other key features in Release 15.0(1)M include the following:
IP Routing
• Graceful OSPF Restart (RFC 3623) (Helper Mode Only)
• Graceful Restart for OSPFv3 (RFC 5187) (Helper Mode Only)
• OSPF Graceful Shutdown
• OSPF Generic Time to Live (TTL) Security Check (GTSM)
• Performance Routing (PfR) Protocol Independent Route Control (PIRO)
• Performance Routing (PfR) EIGRP mGRE DMVPN Hub-and-Spoke Support
• BGP Graceful Restart per Neighbor
• Intermediate System-to-Intermediate System (IS-IS) BFD Support
• IS-IS VRF Support
• MPLS VPN - Inter-AS Option AB
• BGP Route Target Changes Without PE-CE Impact
• IS-IS MIB Support
• MPLS VPN-BGP Local Convergence
IP Multicast
• IGMP Static Group Range Support
• IP Multicast Load Splitting - Equal Cost Multipath (ECMP) using S, G and Next-hop
• IPv4 and IPv6 Multicast Address Group Range Support
• Multicast MIB VRF Support
• Multicast VPN Extranet Support
• Multicast VPN VRF Select
• PIM Triggered Joins
Call Admissions Control Enhancements for Voice and Video
• RSVP Interface-based Receiver Proxy
• RSVP Fast Link Repair
• RSVP VRF lite Admission Control
High Availability
• BFD client for IPv4 Static Routes
• BFD VRF support
• BFD Support for WAN Interfaces
Embedded Management
• EEM policy description display
• EEM policy AAA bypass
• Multiple CLI execution in one TCL command
Security
• Lightweight IPS Engines for Signatures
• New Default IOS IPS Category signatures
• Chaining of Traffic Scanning (Regular Expression) Tables for IPS
• Configurable Threshold Limits for IPS Signatures
• GET VPN VRF-Aware GDOI on GM
• Ability to Disable Volume-based IPSec Lifetime Rekey
• DMVPN Enhancements
Voice
• Cisco Unified Border Element (CUBE) Support for SRTP-RTP Internetworking
• CUBE Support for Out-of-dialog SIP OPTIONS Ping Messages to Monitor SIP Servers
• UC Trusted Firewall Control Version 2
• Cisco UC Release 8.0 SAF Support
Additional details on new features in Release 15.0(1)M are available at http://www.cisco.com/en/US/docs/ios/15_0/15_0m1/15_0_1_m_newfeatlist.html
Cisco IOS Software Release 15.1(1)\T
• Cisco Integrated Services Routers Generation 2 3945E and 3925E Series
• Web Services Management Agent (WSMA) support for Transport Layer Security (TLS)
• IP SLA Engine 3
• Configurable MPLS MTU size for Layer 2 traffic over GRE Tunnels
• Unified Survivable Remote Site Telephony 8.0
• Smart Call Home Support for Integrated Services Routers (ISR)
Additional details on new features in Release 15.1(1)T are available at http://www.cisco.com/en/US/docs/ios/15_1/release/notes/151TFEAT.html
Support Lifecycle and Milestones For Cisco IOS Software Release 15M&T
Figure 5. Release 15M&T Support Lifecycle

Table 1. Cisco IOS Software Release 15.0(1)M milestones
Milestone |
Definition |
Date |
First Customer Shipment (FCS) |
The date the software release is first available to customers on Cisco Software Download Center |
Day 0 |
Maintenance Deployment Point (MD Point) |
Maintenance Deployment (MD) designated M Releases are widely deployable, as proven through extensive system testing, which continues as part of Cisco's ongoing commitment to improve and increase reliability and quality. A set of stringent criteria is used to analyze the quality of the release, such as high customer satisfaction, expansive customer deployment, demonstrated software reliability, and rigorous ongoing testing. |
Typically 9 to 12 months (3rd or 4th maintenance rebuild) after the initial posting (FCS date) of the release on Cisco.com Software Download Center |
End of Sale Date (EoSale) |
The day the release is no longer orderable or included in manufacturing shipments of Cisco hardware. |
Approx. 28-30 months after FCS date |
End of Software Maintenance (EoSM) |
This is the last date that Cisco Engineering may release any final software maintenance releases or software fixes for the release. |
Approx 40-42 months after FCS date |
Each 15 T release receives bug-fix rebuild support for 13 months, plus an additional 6 months support for security/vulnerability issues such as Product Security Incident Response Team (PSIRT) advisories; visit http://www.cisco.com/en/US/products/products_security_advisories_listing.html for more information.
The software support lifecycle for Release 15.1(1)T is illustrated in Figure 6.
Figure 6. Support Lifecycle for Cisco IOS Software Release 15 T

Packaging
Cisco IOS Packaging in Release 15M&T for Cisco routers previously supported in Release 12.4T is shown in Figure 7 below
Figure 7. Cisco IOS Release 15M&T Packaging Framework for Cisco Routers Previously Supported in 12.4T *.

Cisco IOS Packaging for Cisco Integrated Services Routers Generation 2
Figure 8. Cisco IOS Release 15.0(1)M Packaging for ISR G2 1900, 2900, and 3900 Series *

Cisco IOS Software Activation for Integrated Services Routers Generation 2

Cisco will support packaging parity for IPv6 with IPv4, for Cisco Integrated Services Routers Generation 2, starting with Cisco IOS Software Release 15.0(1)M, as well as in future 15 M and 15 T releases. IPv6 feature support for a technology will now be packaged in the same feature set as IPv4.
Additional Information