IPV6
STATELESS AUTOCONFIGURATION
AUTOCONFIGURATION
IPv6 Stateless
Autoconfiguration: the router and the host create an IPv6
address and a default route
IPv6 Stateful Autoconfiguration:
CONFIGURATION
stateless address autoconfiguration
1) duplicate address detection (link-local addr.) 2) host sends router solicitation packet
3) router sends router advertisment packet
4) host builds address from interface identifier
(known) and prefix (sent by router with 3)
5) duplicate address detection again
stateful address autoconfiguration
IPV6 ADDRESSING
IPv6 Addressing rules are covered by multiples
RFC’s
Architecture defined by RFC 2373
Address Types are :
Unicast : One to One (Global, Link local, Site local,
Compatible)
Anycast : One to Nearest (Allocated from Unicast)
Multicast : One to Many
Reserved
A single interface may be assigned multiple IPv6
addresses of any type (unicast, anycast, multicast)
ANYCAST
IPv4 has unicast, broadcast, multicast
IPv6 has no broadcast (uses multicast)
But there’s the new anycast
Sends a packet to the nearest of a set of hosts
iMac
iMac
iMac
Unicast
Anycast
IPV6 ADDRESSING MODEL
Addresses are assigned to interfaces
No change from IPv4 Model
Interface can have multiple addresses
-64 bits of 128
Addresses have scope
Link Local
Site Local
Global
Addresses have lifetime
Valid and Preferred lifetime
Link-Local
NEIGHBOR DISCOVERY (RFC 2461)
Protocol built on top of ICMPv6 (RFC 2463)
combination of IPv4 protocols (ARP, ICMP,…)
Neighbour Discovery:
Determines the link-layer address of a neighbour on
the same link, Duplicate Address Detection
Finds neighbour routers, Keeps track of neighbours
defines ICMPv6 packet types including
Router Solicitation / Router Advertisements
STATELESS AUTOCONFIGURATION
Prefix Advertisement
Advertises prefixes & parameters on a local link.
This information is used by IPv6 nodes to configure their IPv6 addresses
DAD
Ensures that each IPv6 address configured on an
interface using stateless auto configuration is unique
IPv6 Stateless Autoconfiguration
1. IPV6 INTERFACE ID
Cisco 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
STATELESS AUTOCONFIGURATION PROCESS
IPv6 Stateless Autoconfiguration
13
Generate a link local address
Verify this tentative address Is ok. Use a neighbor solicitation
with the tentative address as the target. ICMP type 135
If the address is in use a neighbor advertisement
Message will be returned. ICMP type 136
If no response
Assign the address to the Interface. At this point the
Node can communicate On-link.
STATELESS AUTOCONFIGURATION PROCESS
IPv6 Stateless Autoconfiguration
14
Assign address to Interface.
Node joins the All Routers Multicast group. FF02::1
Sends out a router
Solicitation message to That group. ICMP type 133
Router responds with a Router advertisement.
2. STATELESS AUTOCONFIGURATION
Stage 2: The router replies with a router advertisement.
3. DUPLICATE ADDRESS DETECTION
Duplicate Address Detection (DAD) uses neighbor
solicitation to verify the existence of an address to be configured.
ICMP type = 135
Src = 0 (::) Dst = Solicited-node multicast of A
Data = link-layer address of A Query = what is your link address?
ADDRESS AUTOCONFIGURATION
Stateful:
Problem w stateless: Anyone can connect
Routers ask the new system to go DHCP server
(by setting managed configuration bit)
System multicasts to "All DHCP servers"
IOS COMMANDS
config# ipv6 unicast-routing #int fa0/0
config-if#ipv6 en
#do sh ipv6 int ***this gives the router a link-local address
#ipv6 address FEC0:0:0:123::/64 eui-64 ***giving the router site-local add ***u can do the same for all other routers with the same command as MAC
addresses are unique
#ipv6 address 2001:0:0:123::1/64 ***giving router global address ****u can assign ::2 to the next router
#no shut
#sh ipv6 int br ***show interfaces
config-if #do ping “remote IP address e.g. FE80::20D…” ***Output Interface is “Fastethernet0/0” in full
#ping <IPV6 address>
ENABLE IPV6
STATELESS AUTOCONFIGURATION
Link Local, Site-Local
STATELESS AUTOCONFIGURATION
Ping other configured
router or host
State Interface
STATELESS AUTOCONFIGURATION
Link Local address IP address
STATELESS AUTOCONFIGURATION
IP address assigned Set to
STATELESS AUTOCONFIGURATION
IP address assigned Set to
STATELESS AUTOCONFIGURATION
STATELESS AUTOCONFIGURATION
MULTICAST LISTENER DISCOVERY: SOLICITED NODE MULTICAST GROUP
STATELESS AUTOCONFIGURATION
Advertising that they have
joined Multicast group with the
ANONYMOUS ADDRESSING
Anonymo us, Public
ANONYMOUS ADDRESSING
Anonymous IP was set because
