Ipv6 Applications; Dual Ipv4 And Ipv6 Protocol Stacks - Cisco WS-C2960-24LC-S Software Configuration Manual

Chapter 29 Configuring IPv6 Host Functions
All interfaces on IPv6 nodes must have a link-local address, which is automatically configured from the
identifier (router MAC address) for an interface and the link-local prefix FE80::/10. A link-local address
enables a node to communicate with other nodes on the link and can be used to further configure the
node. Nodes can connect to a network and automatically generate global IPv6 addresses without the need
for manual configuration or the help of a server, such as a DHCP server. With IPv6, a router on the link
uses router advertisement messages to advertise global prefixes and its ability to act as a default router
for the link. A node on the link can automatically configure global IPv6 addresses by appending its
interface identifier (64-bits) to the prefixes (64 bits) included in the router advertisement messages.
The 128-bit IPv6 addresses configured by a node are then subjected to duplicate-address detection (RFC
2462) to ensure their uniqueness on the link. If the advertised prefixes are globally unique, the IPv6
addresses configured by the node are guaranteed to be globally unique. Router solicitation messages,
which have a value of 133 in the ICMP packet header Type field, are sent by hosts at system startup so
that the host can be immediately autoconfigured without waiting for the next scheduled router
advertisement message. IPv6 duplicate-address detection is performed on unicast addresses before they
are assigned to an interface. The switch does not support automatically generated site-local IPv6
addresses.

IPv6 Applications

The switch has IPv6 support for these applications:
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For more information about managing these applications with Cisco IOS, see the "Managing Cisco IOS
Applications over IPv6" section in the Cisco IOS IPv6 Configuration Library at this URL:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a00807fcf4b.
html

Dual IPv4 and IPv6 Protocol Stacks

One technique for transitioning to IPv6 is by using dual IPv4 and IPv6 protocol stacks. Using dual stacks
enables gradual, one-by-one upgrades to applications running on nodes. Applications that are upgraded
to IPv6 use the IPv6 protocol stack, and applications that are not upgraded and support only IPv4 can
coexist with upgraded applications on the same node. New and upgraded applications can use both IPv4
and IPv6 protocol stacks.
The Cisco IOS software supports the dual IPv4 and IPv6 protocol stack technique. When both IPv4 and
IPv6 routing are enabled and an interface is configured with both an IPv4 and IPv6 address, the interface
forwards both IPv4 and IPv6 traffic.
Figure 29-1 shows a router forwarding both IPv4 and IPv6 traffic through the same interface, based on
the IP packet and destination addresses.
OL-8603-04
Ping, traceroute, Telnet, TFTP, and FTP
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
Catalyst 2960 Switch Software Configuration Guide
Understanding IPv6
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