IPv6 extension header

The Extension Header of IPv6 is an optional Header that may follow the basic IPv6 Header. An IPv6 packet can contain one or more extension headers. Of course, there can be no extension headers. These extension headers can have different lengths. The IPv6 Header and extended header of www.2cto.com Replace the IPv4 header and its options. The new extended Header Format enhances the IPv6 function and makes it highly scalable. Different from the options in the IPv4 header, the IPv6 extension header has no limit on the maximum length, so it can accommodate all the extension data required for IPv6 communication. The IPv6 extension header is an optional Header that may follow the basic IPv6 Header. Why is an extension header field designed in IPv6? We know that the IPv4 header contains all the options, so each intermediate router must check whether these options exist. If they exist, they must be processed. This design method will reduce the efficiency of the router to forward IPv4 packets. To solve this problem, related options are moved to the extended header in IPv6. The intermediate vro does not need to process every possible option (in IPv6, each intermediate vro must process the unique extension header that is a hop-by-hop option extension header ), this processing method improves the speed at which the router processes data packets and the forwarding performance. Below are some Extended Headers: www.2cto.com Hop-by-Hop Options header Destination Options header Routing header Fragment header) authentication header encapsulates the Encapsulating Security Payload header. In a typical data packet, not every data packet includes all the Extended Headers. When the intermediate router or target requires some special processing, the sending host will add the corresponding extension header. If there is no extended Header in the packet, that is to say, the packet only includes the basic Header and the upper-Layer Protocol Unit. The value of the Next Header field in the basic Header indicates the upper-layer protocol type. Upper Layer Protocol Data Unit (Upper Layer Protocol Data Unit) The Upper Layer Protocol Data Unit is generally composed of the Upper Layer Protocol header and its payload, the payload can be an ICMPv6 Packet, a TCP packet, or a UDP packet.