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NOTE: As an alternative to stateless autoconguration, network hosts can obtain their IPv6 addresses using the dynamic host
control protocol (DHCP) servers via stateful auto-conguration.
NOTE: Dell Networking OS provides the exibility to add prexes on Router Advertisements (RA) to advertise responses to
Router Solicitations (RS). By default, RA response messages are sent when an RS message is received. Enable the RA response
messages with the ipv6 nd prefix default command in INTERFACE mode.
Dell Networking OS manipulation of IPv6 stateless autoconguration supports the router side only. Neighbor discovery (ND) messages are
advertised so the neighbor can use this information to auto-congure its address. However, received ND messages are not used to create
an IPv6 address.
The router redirect functionality in the neighbor discovery protocol (NDP) is similar to IPv4 router redirect messages. NDP uses ICMPv6
redirect messages (Type 137) to inform nodes that a better router exists on the link.
IPv6 Headers
The IPv6 header has a xed length of 40 bytes. This xed length provides 16 bytes each for source and destination information and eight
bytes for general header information.
The IPv6 header includes the following elds:
• Version (4 bits)
• Trac Class (8 bits)
• Payload Length (16 bits)
• Next Header (8 bits)
• Hop Limit (8 bits)
• Source Address (128 bits)
• Destination Address (128 bits)
IPv6 provides for extension headers. Extension headers are used only if necessary. There can be no extension headers, one extension
header or more than one extension header in an IPv6 packet. Extension headers are dened in the Next Header eld of the preceding IPv6
header.
IPv6 Header Fields
The 40 bytes of the IPv6 header are ordered, as shown in the following illustration.
Figure 56. IPv6 Header Fields
IPv6 Routing
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