Send document comments to nexus7k-docfeedback@cisco.com.
3-12
Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
OL-20002-02
Chapter 3 Configuring IPv6
Information About IPv6
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.
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.
Table 3-4 IPv6 DNS Record Types
Record Type Description Format
AAAA Maps a hostname to an IPv6 address.
(Equivalent to an A record in IPv4.)
www.abc.test AAAA 3FFE:YYYY:C18:1::2
PTR Maps an IPv6 address to a hostname.
(Equivalent to a PTR record in Ipv4.)
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
To Next Page
Loading...
