A Method for the Transmission of IPv6 Packets over Ethernet Networks
obsoleted by
- rfc-2464 — Transmission of IPv6 Packets over Ethernet Networks
Extracted elements (16)
The 80-bit link-local prefix FE80:: combined with a 48-bit Ethernet address (with 16 zero bits in between) was chosen to align the interface identifier directly at the end of the 128-bit address, simplifying address formation from the existing IEEE 802 identifier without requiring EUI-64 expansion (which was introduced in the successor RFC 2464).
A different MAC address set manually or by software should not be used as the address token for stateless autoconfiguration.
An IPv6 address prefix used for stateless autoconfiguration of an Ethernet interface must be 80 bits in length.
If a Router Advertisement is received with an MTU option specifying an MTU larger than 1500, or larger than a manually configured value less than 1500, that MTU option must be ignored.
The default MTU size for IPv6 packets on an Ethernet is 1500 octets. This size may be reduced by a Router Advertisement MTU option or by manual configuration.
The Ethernet type code in the frame header must contain the value 86DD hexadecimal to indicate an IPv6 payload.
An IPv6 packet with a multicast destination address DST is transmitted to an Ethernet multicast address formed as: first two octets 33:33, followed by the last four octets of DST in most-to-least-significant order.
IPv6 packets are transmitted in standard Ethernet frames with Ethernet type code 86DD hexadecimal. The data field contains the IPv6 header followed immediately by the payload, and possibly padding octets to meet the minimum Ethernet frame size.
The address token for an Ethernet interface is the interface's built-in 48-bit IEEE 802 address, in canonical bit order with octets in the same order as they appear in an Ethernet frame header. The individual/group bit is in the first octet and the OUI is in the first three octets.
The Ethernet Address field in the Source/Target Link-layer Address option is the 48-bit IEEE 802 address in canonical bit order. This is the address the interface currently responds to and may differ from the built-in address used as the address token.
The IPv6 link-local address for an Ethernet interface is formed by appending the interface's 48-bit IEEE 802 address to the 80-bit prefix FE80::, resulting in a 128-bit address.
The RFC explicitly states that security issues are not discussed in this memo. No authentication or integrity mechanisms are specified for IPv6-over-Ethernet frame transmission.
The Ethernet frame for IPv6 consists of: 6-octet Destination Ethernet address, 6-octet Source Ethernet address, 2-octet Ethertype (86DD hex), followed by the IPv6 header and payload.
The Ethernet multicast address for an IPv6 multicast destination DST is: 33:33:DST[13]:DST[14]:DST[15]:DST[16], where DST[13]-DST[16] are the last four octets of the 16-octet IPv6 destination address.
The link-local address wire layout is: FE80 followed by six zero octets (80-bit prefix), then 2 zero octets, then the 48-bit Ethernet address — totaling 16 octets.
The Source/Target Link-layer Address option for Ethernet has a 1-octet Type field (1=Source, 2=Target), a 1-octet Length field with value 1 (in units of 8 octets), and a 6-octet Ethernet Address field in canonical bit order.