Dual Ipv4 And Ipv6 Protocol Stacks - Cisco AP776A - Nexus Converged Network Switch 5020 Configuration Manual

About IPv6
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Figure 47-8
00:2c:04:00:FF:56
A node on the link can automatically configure site-local and global IPv6 addresses by appending its
interface identifier (64 bits) to the prefixes (64 bits) included in the RA messages. The resulting 128-bit
IPv6 addresses configured by the node are then subjected to duplicate address detection to ensure their
uniqueness on the link. If the prefixes advertised in the RA messages are globally unique, then the IPv6
addresses configured by the node are also guaranteed to be globally unique. Router solicitation
messages, which have a value of 133 in the Type field of the ICMP packet header, are sent by hosts at
system startup so that the host can immediately autoconfigure without needing to wait for the next
scheduled RA message.

Dual IPv4 and IPv6 Protocol Stacks

The dual IPv4 and IPv6 protocol stack technique is one technique for a transition to IPv6. It enables
gradual, one-by-one upgrades to applications running on nodes. Applications running on nodes are
upgraded to make use of the IPv6 protocol stack. Applications that are not upgraded—they support only
the IPv4 protocol stack—can coexist with upgraded applications on the same node. New and upgraded
applications simply make use of both the IPv4 and IPv6 protocol stacks. (See
Figure 47-9
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A new API has been defined to support both IPv4 and IPv6 addresses and DNS requests. An application
can be upgraded to the new API and still use only the IPv4 protocol stack. The Cisco MDS NX-OS
supports the dual IPv4 and IPv6 protocol stack technique. When an interface is configured with both an
IPv4 and an IPv6 address, the interface will accept and process both IPv4 and IPv6 traffic.
Cisco MDS 9000 Family CLI Configuration Guide
47-10
IPv6 Stateless Autoconfiguration
MAC address:
Host autoconfigured
address is:
prefix received + interface ID
Dual IPv4 and IPv6 Protocol Stack Technique
Existing application
TCP UDP
IPv4 IPv6
0x86dd
Data link (Ethernet)
Chapter 47
Sends network-type
information
(prefix, default route, and so on)
Upgraded application
TCP UDP
IPv4 IPv6
0x0800 0x86dd
Datal link (Ethernet)
Configuring IPv6 for Gigabit Ethernet Interfaces
Figure 47-9.)
Frame
protocol ID
OL-18084-01, Cisco MDS NX-OS Release 4.x