Cisco CATALYST 2960

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Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
OL-26520-01
Chapter 35 Configuring IPv6 Host Functions
Understanding IPv6
Neighbor discovery throttling ensures that the switch CPU is not unnecessarily burdened while it is in
the process of obtaining the next hop forwarding information to route an IPv6 packet. The switch drops
any additional IPv6 packets whose next hop is the same neighbor that the switch is actively trying to
resolve. This drop avoids further load on the CPU.
IPv6 Stateless Autoconfiguration and Duplicate Address Detection
The switch uses stateless autoconfiguration to manage link, subnet, and site addressing changes, such as
management of host and mobile IP addresses. A host autonomously configures its own link-local
address, and booting nodes send router solicitations to request router advertisements for configuring
interfaces.
For more information about autoconfiguration and duplicate address detection, see the “Implementing
IPv6 Addressing and Basic Connectivity” chapter of Cisco IOS IPv6 Configuration Library on
Cisco.com.
IPv6 Applications
The switch has IPv6 support for these applications:
• Ping, traceroute, and Telnet
• Secure Shell (SSH) over an IPv6 transport
• HTTP server access over IPv6 transport
• DNS resolver for AAAA over IPv4 transport
• Cisco Discovery Protocol (CDP) support for IPv6 addresses
For more information about managing these applications, see the “Managing Cisco IOS Applications
over IPv6” chapter and the “Implementing IPv6 Addressing and Basic Connectivity” chapter in the
Cisco IOS IPv6 Configuration Library on Cisco.com.
Dual IPv4 and IPv6 Protocol Stacks
On a Catalyst 2960 switch, you must use the dual IPv4 and IPv6 template to allocate ternary content
addressable memory (TCAM) usage to both IPv4 and IPv6 protocols.
Figure 35-1 shows a router forwarding both IPv4 and IPv6 traffic through the same interface, based on
the IP packet and destination addresses.
Figure 35-1 Dual IPv4 and IPv6 Support on an Interface
122379
3ffe:yyyy::1
10.1.1.1
IPv6
IPv4