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Product Bulletin
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New Software Features
The following new features of the Cisco IOS Software Release 12.2(40)SG are applicable only for
the new Supervisor Engine 6-E, unless otherwise stated.
Dynamic Multi-Protocol Ternary Content Addressable Memory (TCAM)
The ternary content addressable memory 4 (TCAM4) is an architectural innovation that enables
wire-speed forwarding performance in the new Supervisor Engine 6-E. Dynamic multi-protocol
TCAM is a feature of the TCAM4 that enables wire-speed forwarding performance for IPv4, IPv6,
unicast Reverse Path Forwarding (uRPF), and multicast (both IPv4 and IPv6) routes, while
optimizing memory resources.
Customers who deploy a mix of IPv4 and IPv6 features in their network will benefit from the
increased capacity and performance resulting from DMPT optimization. With the new dynamic
multi-protocol TCAM, small number of IPv6 routes will not adversely affect the number of IPv4
routing entries. Lastly, Cisco IOS Software Release 12.2(40)SG automatically handles DMPT
optimization, allowing for greater simplicity and ease of management.
Service-Aware Resource Allocation
Wire-speed security and quality-of-service (QoS) services are enabled by the TCAM4 on the new
Supervisor Engine 6-E. With the previous generation of TCAMs, half of the TCAM memory space
was strictly allocated for security features, with the other half allocated for QoS features. With the
new TCAM4 Service Aware Resource Allocation (SARA) feature, this strict half-and-half allocation
is eliminated. This allows the customer to have the ultimate flexibility of deploying service features
at wire speed. For customers who exclusively use either one of the service features (security or
QoS), this represents an almost twofold increase in the capacity of the classification entries. As
above, Cisco IOS Software Release 12.2(40)SG automatically allocates the TCAM4 memory
space for security or QoS services, resulting in simple and easy configuration of the switch.
uRPF Strict Mode
The uRPF feature mitigates problems caused by the introduction of malformed or forged (spoofed)
IP source addresses into a network by discarding IP packets that lack a verifiable IP source
address. uRPF deflects denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks
by forwarding only packets that have source addresses that are valid and consistent with the IP
routing table. This helps to protect the network of the customer, the ISP, and the rest of the
Internet. When using uRPF in strict mode, the packet must be received on the interface that the
router would use to forward the return packet. uRPF strict mode is supported for both IPv4 and
IPv6 prefixes.
IPv6 Forwarding in Hardware
IPv6 is the next-generation IP protocol, designed to solve numerous problems that the original IP
version 4 has, such as address space limitations. Cisco IOS Software Release 12.2(40)SG
supports hardware-based IPv6 unicast and multicast forwarding. The primary IPv6 features
supported in hardware are:
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IPv6 Cisco Express Forwarding
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IPv6 hardware support for forwarding unicast and multicast traffic
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IPv6 PIM Sparse Mode