Ipv6 With Embedded Ipv4 Addresses - Brocade Communications Systems 8 Administrator's Manual

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IPv6 with Embedded IPv4 Addresses

Only IPv4-compatible IPv6 addresses are supported. Only the low-order 32-bits of the address can
be used as an IPv4 address (high-order 96 bits must be all zeros). This allows IPv6 addresses to be
used on an IPv4 routing infrastructure that supports IPv6 tunneling over the network. Both
end-points of the circuit must be configured with IPv4-compatible IPv6 addresses. IPv4 to IPv6
connections are not supported. IPv4-mapped IPv6 addresses are not supported, because they are
intended for nodes that support IPv4 only when mapped to an IPv6 node.
Fabric OS FCIP Administrator's Guide
53-1001766-01
The IPv6 8-bit Traffic class field will be defined by the configured Differentiated Services field
for IPv6 (RFC 2474). The configuration of this will be done on the FCIP circuit using the
Differentiate Services Code Point (DSCP) parameters to fill the 6-bit DSCP field.
Flow labels are not supported on this IPv6 implementation. The 20-bit Flow Label field will be
defaulted to all zeros.
The IPv6 optional Extension Headers will not be supported. The optional Extension Headers
will not be inserted on packet egress and ingress packets that contain these headers will be
discarded. The next header field must be the Layer 4 protocol for this implementation.
Parts of the Neighbor Discovery protocol (RFC 4861) will be used in this implementation. With
this feature.
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Hop limits (TTL) are learned from the Neighbor Advertisement packet.
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The link-local addresses of neighbors are learned from Neighbor Advertisement.
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Netmask is deprecated in IPv6. Instead, the prefix length notation is used to denote
subnets in IPv6 (the so-called CIDR (Classless Inter-Domain Routing) addressing syntax).
Prefix length of neighbor nodes is learned from the received Neighbor Advertisement
packet.
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IPv6 link-local address for each GE interface is configured at start up and advertised to
neighbors. The user does not configure the interface link-local address.
The 8-bit hop limit field will be filled by the learned value during Neighbor Discovery.
IPv6 addresses and routes must be statically configured by the user. Router Advertisements
and IPv6 Stateless Address Autoconfiguration (RFC 2462) are not supported.
The Neighbor Discovery ICMPv6 Solicitations and Advertisements will be transmitted to the
Layer-2 Ethernet multicast MAC address derived from the IPv6 source address (RFC 2464).
ICMPv6 message types in RFC 4443 and ICMPv6 message types used for Neighbor Discovery
are supported.
Path MTU Discovery (RFC 1981) will not be supported on this implementation, requiring static
configuration of MTU size. The maximum MTU supported will be 1500 bytes (including the 40
byte fixed IPv6 header), the same as for IPv4. The minimum MTU allowed will be 1280 bytes
(including the 40 byte fixed IPv6 header). Any network used for IPv6 FCIP circuits must support
an MTU of 1280 or larger. IPv6 fragmentation is not supported. The Layer 4 protocol will
ensure that the PDU is less than the MTU (including headers).
IPv6 addressing currently cannot be used when implementing IPsec. This will be supported in
a later Fabric OS release.
Support for IPv6 Addressing
2
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