IPv4 Address and IPv6 equivalents ALTTC, Ghaziabad
Methods of Configuration of the Host ALTTC, Ghaziabad Host Configuration ManualAuto Autoconfiguration StatefulStateless
Types of the Autoconfiguration ALTTC, Ghaziabad Autoconfiguration Option Stateless Stateful DHCPv6 Both
IPv6 Address Example IPv6 An IPv6 address can have different states Tentative address- This is an address that has not yet been defined ie the state prior to the assignment Preferred Address-This is an address that has been defined to an interface & can be used without any restriction. Deprecated address-The address whose life time is about to expire & no longer be used as a source address for newly established connection
IPv6 Address Representation EUI 64 IPv6 IPv6 uses the extended universal identifier (EUI)-64 format to do stateless autoconfiguration. This format expands the 48-bit MAC address to 64 bits by inserting “FFFE” into the middle 16 bits. To make sure that the chosen address is from a unique Ethernet MAC address, the universal/local (U/L bit) is set to 1 for global scope (0 for local scope).
Stateless Autoconfiguration Example IPv6 MAC address: 00:0A:AC:01:C9:1C EUI 64 Address: 20A:ACFF:FE01:91C Some OS compute random number using MAC to create 64bit unique Interface Id (masking MAC) The prefix for link-local addresses is FE80::/64. Local Link Address becomes FE80::20A:ACFF:FE01:91C/64
Stateless Autoconfiguration Example If Unique Local Network Prefix given by Router is FC00::1/64, The Unique Local Address Becomes: FC00::1 :20A:ACFF:FE01:91C/64
Stateless Autoconfiguration Example Source : FE80::20A:ACFF:FE01:91C/64 Destination: FF02::2 Source : Router Interface Address Destination: FF02::1 Router Solicitation is sent on FF01::2 (All Router Multicast Address) and Advertisement sent on FF01::1 (All Node Multicast Address)
Stateless Autoconfiguration Example Following steps are performed, when node is autoconfigured. A link local address is generated by using link local prefix FE80::/64 & an EUI-64 derived interface identifier. It is in tentative state. The node joins the multicast group (FF02::1) the all node multicast group & the solicit node multicast groupfor the tentative address A neighbor solicitation message is sent out with the tentative address as the target address If a neighbor advertisement message is received, indicates that another node is on the local link is using the tentative address & the address autoconfiguration stop & manual configuration must be performed.
Stateless Autoconfiguration Example If no neighbor advertisement message is received,the tentative link local address is assumned to be unique & valid & then asssigned to the interface. The state of the address changes to “PREFFERED” In order to determine the Router,the host sends a router solicitation message to the all router multicast group FF02::2 ie request all routers connected to the link to send a router advertisement message for prefix information All routers on the link reply with a router advertisement & host generate an address by combining the prefix with the interface identifier.
Stateless Autoconfiguration Example Router periodically send RA. Host senda a router solicitation message to request an immediate RA rather than waiting the next RA If no RA message is received, the host uses the address configuration protocol to obtain address & other configuration parameters. If RA is received, the hop limit, MTUreachacle time etc. parameters are set.
Stateless Autoconfiguration Stateless Address Configuration (IP Address, Default Router Address) Routers sends periodic Router Advertisement Node gets prefix information from the Router advertisement and generates the complete address using its MAC address Global Address=Link Prefix + EUI 64 Address Router Address is the Default Gateway
Stateless Autoconfiguration Example Using Link-Local Address, Router Solicitation is sent by Host on FF02::2 (All Router Multicast Address) Router sends Advertisement on FF02::1 (All Node Multicast Address) If Global Unicast Network Prefix given by Router is 2001:db8::23:1/64, The Global Unicast Address Becomes: 2001:db8::23:1 :20A:ACFF:FE01:91C/64
DHCPv6 Stateful Configuration Provides not only IP address, also other configuration parameters like DNS IPv6
DHCPv6 DHCP uses the following multicast address. All_DHCP_Relay_Agents_and_Servers) FF02::1:2 All DHCP agents (server & relay) are member of this multicast group. DHCP client use this multicast address to reach DHCP agent IPv6
DHCPv6 Client Initiates requests on a link to obtain configuration parameters use its link local address to connect the server Send requests to FF02::1:2 multicast address (All_DHCP_Relay_Agents_and_Servers)
DHCPv6 Relay Agent/ DHCPv6 Server node that acts as an intermediary to deliver DHCP messages between clients and servers is on the same link as the client Is listening on multicast addresses: All_DHCP_Relay_Agents_and_Servers (FF02::1:2)
DHCPv6 The following UDP ports are used with DHCPv6: UDP port 546 (client port) DHCP servers use this port as the destination port to reach DHCP relays or DHCP client. Used by DHCP relay agents as the destination port to reach DHCP clients. UDP port 547; Agent port DHCP clients use this port as the destination port to reach DHCP agents. DHCP relays use this port as the destination port to reach DHCP server.
Client Server Message Exchange Typical 4 message exchange sequence Solicit from client Advertise from server Request from client Reply from Server Typical 2 message exchange sequence Information Request from client Reply from server ALTTC, Ghaziabad
DHCPv6 Client Messages Solicit (1)- Used by the clients to locate DHCP server Advertise(2)- Used by the server as a response to Solicit Request (3)- Used by the clients to get information from server Confirm (4)- Used by the clients to verify that their addresses & configuration parameters are still valid Renew (5)- Used by the client to renew the configuration ALTTC, Ghaziabad
DHCPv6 Client Messages Rebind (6)- Used bye the client to extend the lifetime of their addresses Reply(7)- Used by the DHCP server responding to Request, Confirm, Rebind, Release & decline messages Release (8)- Used by the client to release their addrerssses. Decline (9) ALTTC, Ghaziabad
DHCPv6 Server Messages Reconfigure (10)- Used by the DHCP sever to inform clients that server has new or updated information Information(11) Relayed messages – Relay Forward (12) Used bye the DHCP relay to forward client messages to server. – Relay Reply (13) Used by DHCP server to send messages to client through relay. ALTTC, Ghaziabad