Cisco Cisco IOS Software Release 12.0 S

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Cross-Platform Release Notes for Cisco IOS Release 12.0S
OL-1617-14 Rev. Q0
  New and Changed Information
New Software Features in Cisco IOS Release 12.0(21)S
Modular QoS CLI (MQC) Support
QoS Policy Propagation via Border Gateway Protocol (QPPB)
Sampled V5 NetFlow
Traffic Shaping
IP Source Tracker
Platform: Cisco 12000 series
The IP Source Tracker feature allows you to gather information about the traffic flowing to a host that 
is suspected to be under attack and also allows you to easily trace an attack back to its entry point into 
the network.
The IP Source Tracker feature provides a uniform, scalable service for tracking Denial of Service (DoS) 
attacks. Because this feature is supported on Engine 0, 1, 2, and 4 (in future releases, Engine 3) line 
cards, it allows you to track DoS attacks across your entire network.
The IP source tracker generates all the necessary information in an easy-to-use format to track the 
network entry point of a Denial of Service (DoS) attack. You also can track multiple IPs at the same time. 
see the following document for further information about the IP Source Tracker feature:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/120s21/ipst.htm
Multicast Forwarding in Cisco 12000 Series Internet Routers
Platform: Cisco 12000 series
The Multicast Forwarding feature on Engine 2 line cards in Cisco 12000 series Internet routers allows 
the packet switching ASIC (PSA) to forward IPv4 packets instead of having multicast traffic sent to the 
CPU of a line card for slower path processing.
PSA-based multicast forwarding is supported on the following Cisco 12000 series Engine 2 line cards:
1-port OC-48c/STM-16c DPT
1-port OC-48c/STM-16c POS/SDH
3-port Gigabit Ethernet
4-port OC-12c/STM-4c POS/SDH
8-port OC-3c/STM-1c POS/SDH
16-port OC-3c/STM-1c POS/SDH
Normally IP packets are switched on the CPU of a line card using Multicast Distributed Fast Switching 
(MDFS). This method reduces the load on the Route Processor (RP) and frees it to perform only router 
lookups. PSA-based multicast forwarding, however, provides even higher speed switching than MDFS.
Because packet forwarding is performed in the line card PSA hardware, higher forwarding rates are 
possible. Also, more CPU resources are free to perform other features and control plane processes, such 
as Cisco Express Forwarding (CEF).
The implementation of the Multicast Forwarding feature on Cisco 12000 series Internet routers is 
compatible with multicast routing protocols, such as Protocol Independent Multicast dense mode 
(PIM-DM), PIM sparse mode (PIM-SM), and single source multicast (SSM).