IPv6
IPv6 is the abbreviation of Internet Protocol version 6, in which Internet protocol is translated as “Internet Protocol“. It is the next-generation IP protocol designed by the IETF (Internet Engineering Task Force) to replace the current version of the IP protocol (IPv4).
STP (Spanning Tree Protocol)
The protocol can be applied to the loop network to achieve path redundancy through a certain algorithm. At the same time, the loop network is pruned into a tree network without loop, so as to avoid the proliferation and infinite circulation of packets in the loop network.
The basic principle of STP is to determine the topology of the network by passing a special protocol message between switches (this protocol message is called “configuration message” in IEEE 802.1d). The configuration message contains enough information to ensure that the switch completes the spanning tree calculation.
The main application of spanning tree protocol is to avoid network loopback in LAN and solve the problem of “broadcast storm” in looped Ethernet network. In a sense, it is a network protection technology, which can eliminate circular connections caused by errors or accidents.
The requirements of this small experiment are very simple, and the principle of implementation is also very clear. Compared with tunnel configuration, the advantage of 6to4 channel is to automatically establishes a tunnel. Through special addressing, he can extract the IPv4 address from the IPv6 destination address as the destination address, and then route on the IPv4 network[ccnp 300-41 0 exam cost]. In this way, there is no need to statically set the destination address of the channel, which really saves a lot of management overhead. Points needing attention:
(1) The address used in IPv6 network must be the prefix of 2002:: /16, which is the need of addressing. Because the IPv6 IGP routing protocol is not running between the routers that establish 6to4 channels, all routes still rely on static, so the prefix programming must be in the form of 2002:: /16, otherwise it cannot be routed. The prefix in the IPv6 network should be consistent, otherwise there must be problems.
(2) The tunnel port does not need to set the destination address, because the channel is in the form of one-to-many, and the addressing is realized by relying on a special address. The embedded IPv4 address in 2002:xxxx:xxxx:: /48 can be extracted automatically, and then routed to another channel endpoint through the IPv4 domain. Therefore, the compilation is very important. It must correspond to the source address of the channel. In addition, there are 16-bit subnet bits left, so the address allocation space is still sufficient.
(3) As for the source address of tunnel, I personally think it is better to use the loopback address, which can also provide some line redundancy (Lenovo BGP Peer Establishment). However, we must map with the IPv6 address to form the prefix /48 of the IPv6 network, which is the key to the success of 6to4!
(4) Tunnel may not need an IPv6 address, but it must be available for an IPv6 address.
(5) After the channel is established, a static route is established on the 6to4 router to point to the tunnel, and then the route is republished to its own IPv6 network. （ipv6 route 2002：：/16 tunnel x）
