Interface and hardware component configuration guide, cisco ios xe release 3s 2 manually configured ipv6 over ipv4 tunnels overlay tunnels for. Automatic ipv4 compatible tunnels this kind of tunnel uses ipv4 compatible ipv6 addresses for tunnel interfaces. The ipv4compatible ipv6 tunneling mechanism provides a way to automatically tunnel ipv6 traffic in ipv4 packets. In particular it allows a site to run both ipv4 and ipv6 in coexistence, without having to configure ipv6 hosts either with ipv4 compatible addresses or with tunnels. Tunneling provides a way to use an existing ipv4 routing infrastructure to carry ipv6 traffic. Mar 19, 2017 overlay tunneling encapsulates ipv6 packets in ipv4 packets for delivery across an ipv4 infrastructure a core network or the figure below. Internet protocol version 6 is the most recent version of the internet protocol, the communications protocol that provides an identification and location system for computers on networks and routes traffic across the internet. The downside of multipoint ipv6 tunnels is that they dont support ipv6 igps. Automatic 6to4 allows pockets of ipv6 to be connected. The tunnel destination is not specified but is calculated from the ipv4 address embedded in the destination ipv6 address.
Another proposal is to allocate ipv4compatible addresses on demand and use ipv4 in ipv6 tunneling to bridge the ipv6only routers. Lets dive in the automatic 6to4 tunnel to see how it works. Uses ipv4 protocol type 41 also used for isatap, ipv6ip manual tunnels. Basically, ipv6 packets are placed inside ipv4 packets, which are routed through the ipv4 routers. All documentation i have found use mpbgp because this protocol is able to pass the next hop address in this format 1. An ipv4compatible tunnel is typically used only between two ipv6 domains, but a 6to4 tunnel is used to connect two or more ipv6 domains. Some examples show using bgp for dynamic routing with this.
The ipv6 over ipv4 mechanism is intended to take its place in the range of options available for transition from ipv4 to ipv6. These addresses are taken from 96 address comprised of the first 96 bits containing all zeros and the last 32 bits are derived from the ipv4 address. Automatic tunnels ipv6 administration guide oracle docs. The key to a successful ipv6 transition is compatibility with the existing. Late 1980s exponential growth of the internet late 1990. Mar 28, 2012 an ipv4 compatible tunnel is typically used only between two ipv6 domains, but a 6to4 tunnel is used to connect two or more ipv6 domains. How to configure ipv6 automatic ipv4compatible tunnels configuring ipv4compatible ipv6 tunnels performthistasktoconfigureipv4compatibleipv6tunnels. The ietf is working on a better solution for ipv6only interoperability with ipv4only nodes. Oracle solaris includes 6to4 tunnels as a preferred interim method for making the transition from ipv4 to ipv6 addressing. The 6to4 tunnels can be conceptualised as a big frame relay cloud where each endpoint is address as per the rule 2002. Finding feature information, page 1 information about ipv6 automatic ipv4compatible tunnels, page 1 how to configure ipv6 automatic ipv4compatible tunnels, page 4. Ipv4 compatible ipv6 tunnels were initially specified in rfc 2893, along with configured tunnels. The following figure illustrates the tunneling mechanism through ipv4 routers r.
As with ipv4compatible ipv6 tunnels, we will not specify a tunnel destination. Interface and hardware component configuration guide, cisco ios release 15s 4 ipv6 automatic ipv4compatible tunnels. Hosts that are capable of automatic tunneling use special ipv6 addresses. In december 1998, ipv6 became a draft standard for the ietf, who subsequently ratified it as an internet standa. This feature provides support for ipv6 automatic ipv4compatible tunnels.
Ipv6 sites or hosts connected using this method do not require ipv4 compatible ipv6 addresses or configured tunnels. They make use of ipv4compatible ipv6 addresses, which are made up of 96 zeros followed by 32bit ipv4 addresses. At the network layer, the packets of the communication need to be identified with the source and destination addresses of the two end systems. Ipv4compatible ipv6 tunnels were initially specified in rfc 2893, along with configured tunnels. You can only have 1 6to4 and one ipv4 comptible tunnel on a router, and theyd best have different source interfaces so the rotuer can tell inbound traffic apart, as both use ip. In particular it allows a site to run both ipv4 and ipv6 in coexistence, without having to configure ipv6 hosts either with ipv4compatible addresses or with tunnels. Ipv6 was developed by the internet engineering task force to deal with the longanticipated problem of ipv4 address exhaustion.
With ipv4, this means that each packet has a 32bit source address and a 32bit destination address in the layer 3 header. A comparison of ipv6 over ipv4 tunnel mechanisms ietf tools. These tunnels can originate either on a dualstack host or on a dualstack router by configuring an automatic tunneling network interface. By using overlay tunnels, you can communicate with. An ipv6 address format that employs embedded ipv4 addresses. Automatic tunnels require ipv4 compatible addresses. An internet protocol version 6 address ipv6 address is a numerical label that is used to identify a network interface of a computer or a network node participating in an ipv6 computer network and for locating it in the network. Automatic tunnels can be used to connect ipv6 nodes when ipv6 routers are not available.
The deployment of ipv6 is also benefiting from some industry trends, such as the replacement of windows xp systems without ipv6 stack enabled by default by windows 7 systems with ipv6 enabled by default. They make use of ipv4 compatible ipv6 addresses, which are made up of 96 zeros followed by 32bit ipv4 addresses. Therefore, these tunnels are pointtomultipoint in nature. They make use of ipv4compatible ipv6 addresses, which are made up of 96 zeros.
One proposal is to use header translators with a way to allocate ipv4compatible addresses on demand. Impediments to ipv6 deployment applications applications applications move to the new apis now transition coexistence techniques a wide range of techniques have been identified and implemented, basically falling into three categories. Ipv4 compatible automatic, uses ipv4compatible ipv6 addresses, 0s in the 96 highorder bits, then the ipv4 address in hex at end. Ipv4 compatible tunnelinterface tunnel 0 tunnel source ethernet 0. Chapter 4 making the transition from ipv4 to ipv6 reference. We dont configure the ipv4 endpoint address ourselves but instead the ipv4 endpoint address will be wrapped in the ipv6 destination address.
Deploying ipv6 over ipv4 tunnels tunneling encapsulates ipv6 traffic within ipv4 packets so they can be sent over an ipv4 backbone, allowing isolated ipv6 end systems and routers to communicate without the need to upgrade the ipv4 infrastructure that exists between them. As with ipv4 compatible ipv6 tunnels, we will not specify a tunnel destination. In this way, ipv6 gains considerable independence of the underlying wide area network and can step over many hops of ipv4 subnets. Tunneling mechanism ipv6 administration guide oracle docs. November 1, 2012 this feature provides support for ipv6 automatic ipv4compatible tunnels. Also note that that the prefix length for a 6to4 address is 16 because of from network point of view, all other 6to4 enabled hosts are on the same layer 2. Ipv4compatible ipv6 tunnels were initially specified in rfc 2893, along with. Overlay tunneling encapsulates ipv6 packets in ipv4 packets for delivery across an ipv4 infrastructure a core network or the figure below. Tunneling is one of the key deployment strategies for both service providers and.
Ipv6 automatic ipv4compatible tunnels last updated. Pay attention that the support of 6to4 tunnels currently lacks on vanilla kernel series 2. To use 6to4 tunnels, you must configure a boundary router on your ipv6 network as one endpoint of the 6to4 automatic tunnel. Stack,tunneling issues like ipv6 automatic tunneling and manually configured. Ip addresses are transmitted in the fields of the packet header to indicate the source and the destination of each network packet. Finding feature information, page 1 information about ipv6 automatic ipv4compatible tunnels, page 1.
Interface and hardware component configuration guide, cisco ios xe release 3s 2. The tunnels always terminate on the dualstack host. In this kind of tunnel point to multipoint the destination addresss of the tunnel is created automatically based on a next hop address converted from ipv4 to ipv6. You then add static routes which advertise the networks. Automatic ipv4compatible tunnels use ipv4compatible ipv6 addresses.
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