Dns For Ipv6; Path Mtu Discovery For Ipv6; Cdp Ipv6 Address Support; Icmp For Ipv6 - Cisco Nexus 7000 Series Configuration Manual

Information About IPv6
S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m .

DNS for IPv6

IPv6 supports DNS record types that are supported in the DNS name-to-address and address-to-name
lookup processes. The DNS record types support IPv6 addresses.
Note IPv6 also supports the reverse mapping of IPv6 addresses to DNS names.
Table 3-4
Record Type
AAAA
PTR

Path MTU Discovery for IPv6

As in IPv4, you can use path MTU discovery in IPv6 to allow a host to dynamically discover and adjust
to differences in the MTU size of every link along a data path. In IPv6, however, fragmentation is
handled by the source of a packet when the path MTU of one link along a given data path is not large
enough to accommodate the size of the packets. Having IPv6 hosts handle packet fragmentation saves
IPv6 router processing resources and helps IPv6 networks run more efficiently.
Note In IPv6, the minimum link MTU is 1280 octets. We recommend that you use an MTU value of 1500
octets for IPv6 links.

CDP IPv6 Address Support

You can use the Cisco Discovery Protocol (CDP) IPv6 address support for neighbor information feature
to transfer IPv6 addressing information between two Cisco devices. Cisco Discovery Protocol support
for IPv6 addresses provides IPv6 information to network management products and troubleshooting
tools.

ICMP for IPv6

You can use ICMP in IPv6 to provide information about the health of the network. ICMPv6, the version
that works with IPv6, reports errors if packets cannot be processed correctly and sends informational
messages about the status of the network. For example, if a router cannot forward a packet because it is
too large to be sent out on another network, the router sends out an ICMPv6 message to the originating
host. Additionally, ICMP packets in IPv6 are used in IPv6 neighbor discovery and path MTU discovery.
The path MTU discovery process ensures that a packet is sent using the largest possible size that is
supported on a specific route.
Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
3-12
IPv6 DNS Record Types
Description
Maps a hostname to an IPv6 address.
(Equivalent to an A record in IPv4.)
Maps an IPv6 address to a hostname.
(Equivalent to a PTR record in Ipv4.)
Chapter 3
Format
www.abc.test AAAA 3FFE:YYYY:C18:1::2
2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.8.1.c.0
.y.y.y.y.e.f.f.3.ip6.int PTR www.abc.test
Configuring IPv6
OL-20002-02