Operation Manual – IPv6 ManagementH3C S5600 Series Ethernet Switches Chapter 1 IPv6 Configuration1-3VI. Support for QoSThe Flow Label field in the IPv6 header allows the device to label packets in a flow andprovide special handling for these packets.VII. Enhanced neighbor discovery mechanismThe IPv6 neighbor discovery protocol is implemented by a group of Internet ControlMessage Protocol Version 6 (ICMPv6) messages. The IPv6 neighbor discoveryprotocol manages message exchange between neighbor nodes (nodes on the samelink). The group of ICMPv6 messages takes the place of Address Resolution Protocol(ARP), Internet Control Message Protocol Version 4 (ICMPv4), and ICMPv4 redirectmessages to provide a series of other functions.VIII. Flexible extension headersIPv6 cancels the Options field in IPv4 packets but introduces multiple extensionheaders. In this way, IPv6 enhances the flexibility greatly to provide scalability for IPwhile improving the processing efficiency. The Options field in IPv4 packets containsonly 40 bytes, while the size of IPv6 extension headers is restricted by that of IPv6packets.1.1.2 Introduction to IPv6 AddressI. IPv6 addressesAn IPv6 address is represented as a series of 16-bit hexadecimals, separated bycolons. An IPv6 address is divided into eight groups, 16 bits of each group arerepresented by four hexadecimal numbers which are separated by colons, for example,2001:0000:130F:0000:0000:09C0:876A:130B.To simplify the representation of IPv6 addresses, zeros in IPv6 addresses can behandled as follows:z Leading zeros in each group can be removed. For example, the above-mentionedaddress can be represented in shorter format as2001:0:130F:0:0:9C0:876A:130B.z If an IPv6 address contains two or more consecutive groups of zeros, they can bereplaced by the double-colon :: option. For example, the above-mentionedaddress can be represented in the shortest format as2001:0:130F::9C0:876A:130B.
