ccna cost of examination

ccna cost of examination.10.2.1 SLAACSLAAC is a method for obtaining IPv6 global unicast addresses without the services of a DHCPV6 server. The core of SLAAC is ICMPv6, which works using ICMPv6 RS (Router Request, ICMPv6 type 133) messages and RA (Router Announcement, ICMPv6 type 134) messages, as described below.1 The client computer is configured in the TCP/IPv6 properties to automatically obtain an IPv6 address. After the IPv6 client generates a link-local address and the DAD (DuplicateAddressDetection) passes, it sends an RS message with the link-local address of its own NIC as the source and the FF02::2 multicast address as the destination to notify the local IPv6 router that it needs RA.2 When a router with unicast routing enabled receives an RS message, it immediately responds by sending an RA message with the link-local address of its own sending interface as the source and the FF02::l multicast address as the destination, containing information such as the IPv6 prefix, prefix length, MTU, and lifetime.3 After the client receives the RA message, it generates the interface ID by EUI-64 or randomly, and then creates an IPv6 address using the IPv6 prefix and prefix length of the received RA message.4 The client sends NS (Neighbor Request, ICMPv6 type 135) with full 0 as the source address and the node request address of the created IPv6 address as the destination address for DAD, if no NA (Neighbor Notice, ICMPv6 type 136) is received, it means that no client on the link is using the same address, and the client can use the IPv6 address at this time.In the Flag field of the RA message of ICMPv6, the first two bits are very important, which are the Managed AddressConfiguration bit (M bit) and the Other CoWguration bit (M bit).Chapter 10 DHCP. 137.When the M bit is 1, it means that the address is not a bit.) When the M bit is 1, it indicates that the IPv6 host on the link uses DHCPv6 to obtain the IPv6 address/prefix; when the O bit is 1, it indicates that the IPv6 host on the link uses DHCPv6 to obtain network configuration parameters other than the IPv6 address/prefix. By default, both the M bit and O bit are 0. Different combinations of M bit and O bit represent the way the client obtains IPv6 address, and the combination of M bit and O bit of RA message Flag field and their meanings are shown in Table 10-1.Table 10-1 RA Message Flag Field M-Bit and O-Bit Combinations and Meanings