From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Tue May 23 2006 - 10:54:30 ART
This feature is used in conjunction with ICMP Neighbor Discovery
for a feature known as Stateless Autoconfiguration. When a host comes
onto the segment it announces itself with ICMP ND Neighbor Advertisement
messages. It also receives announcements from routers in the form of
ICMP ND Router Advertisement messages. These RA messages include the
prefix that is being used for the link. With stateless
autoconfiguration the host takes the prefix being advertised by the
router and generates its own host address from the modified EUI-64
format, giving it an automatically generated unique address in that
subnet. The prefix advertisement is automatic on the router side as
long as router advertisements are enabled, which are on all IPv6 enabled
LAN interfaces as soon "ipv6 unicast-routing" is enabled:
R1:
interface FastEthernet0/0
ipv6 address autoconfig
R4:
ipv6 unicast-routing
!
interface Ethernet0/1
ipv6 address 2001::/64 eui-64
Rack1R4#show ipv6 int e0/1
Ethernet0/1 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::230:94FF:FE7E:E582
Global unicast address(es):
2001::230:94FF:FE7E:E582, subnet is 2001::/64 [EUI] <----
<output omitted>
Rack1R1#show ipv6 int fa0/0
FastEthernet0/0 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::204:27FF:FEB5:2FA0
Global unicast address(es):
2001::204:27FF:FEB5:2FA0, subnet is 2001::/64 [AUTOCONFIG] <---
valid lifetime 2591967 preferred lifetime 604767
<output omitted>
Rack1R4#telnet 2001::204:27FF:FEB5:2FA0
Trying 2001::204:27FF:FEB5:2FA0 ... Open
User Access Verification
Password:
Rack1R1>
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Mathew Fernando
> Sent: Tuesday, May 23, 2006 7:18 AM
> To: ccielab@groupstudy.com
> Subject: "ipv6 address autoconfig" - how does it work?
>
> Hi All,
>
> I am just starting to understand how the command "ipv6 address
> autoconfig" works.
>
> Does this only generate the link local address on the interface?
> If yes, what is the difference between this command and the "ipv6
> enable" which does the same.
>
> What am I missing here?
>
> Thanks
>
> Mathew
>
>
This archive was generated by hypermail 2.1.4 : Thu Jun 01 2006 - 06:33:22 ART