Specifications

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Release Notes for Cisco IOS Release 12.0 S
78-7130-11 Rev. B0
New and Changed Information
New Features in Cisco IOS Release 12.0(9)S
Many of the new features in Cisco IOS Release 12.0 S were originally introduced in other Cisco IOS
releases. For more complete information, refer to the original release.
BGP Policy Accounting
Platforms: Cisco 7200 series; Cisco 7500/RSP series, Cisco 12000 series
BGP Policy Accounting provides a means of charging customers according to the route that their traffic
travels. Trans-Pacific, Trans-Atlantic, satellite, domestic, and other provider traffic can be identified and
accounted for on a per-customer basis when customers are on a unique software interface. This feature
also allows the accounting of traffic to known autonomous system numbers in order to better engineer
and plan network circuit peering and transit agreements.
BGP Policy Accounting classifies IP traffic by autonomous system number or autonomous system
community string and increments packet and byte counters per input interface. It performs this function
using route-maps to classify the traffic into one of eight possible indexes, which represent a traffic
classification.
Distributed Multilink Point-to-Point Protocol
Platforms: Cisco 7500/RSP series
The Distributed Multilink Point to Point Protocol (distributed MLP) feature allows T1/E1 lines to be
combined in a Versatile Interface Processor (VIP) on a Cisco 7500 series router into a bundle that has
the combined bandwidth of multiple T1/E1 lines by using a VIP MLP link. You choose the number of
bundles and the number of T1/E1 lines in each bundle, which allows you to increase the bandwidth of
your network links beyond that of a single T1/E1 line without the need to purchase a T3 line.
Nondistributed MLP can only perform limited links, with CPU utilization quickly reaching 90 percent
with only a few T1/E1 lines running MLP. With distributed MLP, you can increase the total capacity of
the router. See the following document for further information:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120t/120t3/multippp.htm
Low Latency Queueing
Platforms: Cisco 7500/RSP series
The Low Latency Queueing feature brings strict priority queueing to Class-Based Weighted Fair
Queueing (CBWFQ). Strict priority queueing allows delay-sensitive data, such as voice, to be dequeued
and sent first (before packets in other queues are dequeued), giving delay-sensitive data preferential
treatment over other traffic.
Without Low Latency Queueing, CBWFQ provides weighted fair queueing based on defined classes
with no strict priority queue available for real-time traffic. CBWFQ allows you to define traffic classes
and then assign characteristics to that class. For example, you can designate the minimum bandwidth
delivered to the class during congestion.
For CBWFQ, the weight for a packet belonging to a specific class is derived from the bandwidth you
assigned to the class when you configured it. Therefore, the bandwidth assigned to the packets of a class
determines the order in which packets are sent. All packets are serviced fairly based on weight; no class
of packets may be granted strict priority. This scheme poses problems for voice traffic, which is largely
intolerant of delay, especially variation in delay. For voice traffic, variations in delay introduce
irregularities of transmission manifesting as jitter in the heard conversation.