Address Types

IPv6 can use several types of addresses:

• Unicast—Used to identify a single interface, this release of the E-series router product supports the following unicast address types:
  • Global aggregatable—Provides for aggregation of routing prefixes to limit the number of global routing table entries
  • Link-local—Eliminates the need for a globally unique prefix. Local-link addresses allow communications between devices on a local link.
  • Site-local—Used as private addresses to restrict communication to a domain portion.

    Note: IPv6 routers must not forward packets that have site-local source or destination addresses outside the site.

  • IPv4-compatible—Contains a standard IPv4 address in the lower-order 32 bits of the address and zeros in the higher-order 96 bits of the address. For example, the format of an IPv4-compatible IPv6 address is 0:0:0:0:0:0:A.B.C.D (or condensed as ::A.B.C.D). In other words, devices using IPv6 use the entire 128-bit IPv4-compatible IPv6 address, whereas IPv4 devices use the IPv4 address embedded within the lower-order 32-bits of the address. You would use IPv4-compatible IPv6 addresses for devices that must support both IPv4 and IPv6 protocols.
• Multicast—Used for sending packets to multiple destinations. A multicast transmission sends packets to all interfaces that are part of a multicast group. The group is represented by the IPv6 destination address of the packet.
• Anycast – Used for a set of interfaces on different nodes. An anycast transmission sends packets to only one of the interfaces associated with the address, not to all of the interfaces. This interface is typically the closest interface, as defined by the routing protocol.
• Loopback—Used by a node to send an IPv6 packet to itself. An IPv6 loopback address functions the same as an IPv4 loopback address.
• Unspecified—Indicates the absence of an IPv6 address. For example, newly initialized IPv6 nodes may use the unspecified address as the source address in their packets until they receive an IPv6 address.

  Note: IPv6 does not use broadcast addresses; instead, IPv6 uses multicast addresses.

Copyright © 2008, Juniper Networks, Inc. All rights reserved. Trademark Notice.