Table Of Contents
PPPoE Client Enhancement—IP TCP Maximum Segment Size Adjustment
PIM - Protocol Independent Multicast
Product Numbers and Descriptions
Product Bulletin, 1277
Cisco IOS Software
Release 12.1(5)YBIntroduction
This product bulletin describes the new features introduced in Cisco IOS™ Software Release 12.1(5)YB.New Features
PPPoE Client enhancement—IP TCP MSS adjustmentLFI—Link Fragmentation and InterleavingLLQ—Low Latency QueuingPIM—Protocol Independent Multicast (Cisco 805)TX Ring AdjustmentDetailed Information
12.1(5)YB is an early deployment (ED) release. This release delivers new feature enhancements to the Cisco 826, Cisco 827, Cisco 827-4V, and to the Cisco SOHO 77 routers. Also see Cisco IOS 12.1(5)YB release notes at:
/en/US/docs/ios/12_1/12_1yb/release/notes/rn800yb.html for Cisco 800 series and
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121relnt/70series/rn70yb.htm for the Cisco SOHO 77.
PPPoE Client Enhancement—IP TCP Maximum Segment Size Adjustment
Ability to adjust IP tcp-mss size to eliminate the need to manually adjust the MTU size on clients to allow the adjusted Ethernet frames to fit inside a PPPoE packets. At this point only supported over NAT connections. This feature is supported on all images of the Cisco 827.LFI
Link fragmentation and interleaving. This will fragment larger packets into smaller segments over a multi-link interface done over one link. Supported over Multilink PPP interfaces. This feature is supported in the Plus feature sets and on the voice models for all feature sets of the Cisco 827 and the Cisco 827-4V.LLQ
Low Latency Queuing, also known as Priority Queued Class Based Weighted Fair Queuing, PQCBWFQ, but the acronym just was too lengthy. This feature provides classification between applications and sends them into different queues defining a guaranteed bandwidth for that class of traffic. Certain classes of traffic are priority queued directly and thus a low latency is accomplished. Supported over RFC 1483 and Multi-link PPP interfaces. This feature is supported on the Plus feature sets, and on the voice models for all images.PIM - Protocol Independent Multicast
Support for PIM sparse mode on Cisco 805. This allows for multicast traffic to be supported with client on the LAN with handling IGMP on the Cisco 805. Requires the Plus feature sets.TX Ring adjustment
Support for transmit-ring buffer depth adjustments on Cisco 820. The feature allows for optimization of delay characteristics to tune the transmit ring buffer on the ATM interface to a smaller size to better suite voice. This feature is supported on the Plus feature sets.The features delivered with this ED release will be immediately incorporated into the 12.2(2)T release. As such, maintenance for these features should be obtained from the 12.2T release.
For more detailed information about the platforms and features being delivered in 12.1(1)XB, please reference the following documents:
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Release Notes for Cisco 820 series for Cisco IOS Release 12.1(5)YB
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Life Span
12.1(5)YB will be sold until Cisco IOS Software 12.2(2)T is released.Supported Hardware Platforms
Cisco IOS Software Release 12.1(5)YB supports the following platforms:•
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Product Numbers and Descriptions
Cisco IOS Software Release 12.1(5)YB can be ordered using the following product numbers.
Product names ending with = denotes spare part. IP is included in the price of the platforms.Cisco 820 images supports the Cisco 826, Cisco 827, and Cisco 827-4V platforms.