Service Manual
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.
NOTE: Inconsistencies in router advertisement values between routers are logged per RFC 4861. The values checked for
consistency include:
• Cur Hop limit
• M and O ags
• Reachable time
• Retrans timer
• MTU options
• Preferred and valid lifetime values for the same prex
Only management ports support stateless auto-conguration as a host.
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 8
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 46. IPv6 Header Fields
IPv6 Routing
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