From: Scott Morris (swm@emanon.com)
Date: Mon Feb 07 2005 - 21:00:05 GMT-3
You don't NEED consistency at all, it's merely a matter of what makes sense
to you. :)
In the first option you did, the last 63 bits of the address were 0's and
the last bit was a 1. The /64 was your subnet mask.
0000:0000:0000:0001 host portion
In the second option, you told it to use eui-64 which will populate the BIA
address with the inserted scheme in the middle of it as you saw.
02D0:58FF:FE6E:B720 host portion
But you can do whatever your heart desires. It's just what makes sense to
you and what you're trying to accomplish!
It's kinda like in IPv4, I can stick one device as .1 in the /24 and another
as .222 and they can still talk to each other as long as there is subnet
consistency!
HTH,
Scott Morris, MCSE, CCDP, CCIE4 (R&S/ISP-Dial/Security/Service Provider)
#4713, JNCIP, CCNA-WAN Switching, CCSP, Cable Communications Specialist, IP
Telephony Support Specialist, IP Telephony Design Specialist, CISSP
CCSI #21903
swm@emanon.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ccie2be
Sent: Monday, February 07, 2005 6:40 PM
To: Group Study
Subject: Fw: eui-64 option - I think I got it - part 2
And, upon further reflection, I think you don't have to be consistent.
For example, let's say you have routers connected to the same subnet.
rtr A int e0 --------------- e0 rtr B
On rtr A you could use the eui-64 option but on router B you don't use the
eui-64 option.
And, I also think, this is true whether or not the interfaces are LAN or WAN
From ipv6 point of view everything is fine.
While I'm not recommending this - I think the addressing method should be
consistent - ipv6 wouldn't have a problem with this.
Does everyone agree with this assessment?
Tim
> ----- Original Message -----
> From: <Jongsoo.Kim@Intelsat.com>
> To: <ccie2be@nyc.rr.com>
> Sent: Monday, February 07, 2005 6:11 PM
> Subject: RE: eui-64 option - I think I got it
>
>
> > I agree
> >
> > -----Original Message-----
> > From: ccie2be [mailto:ccie2be@nyc.rr.com]
> > Sent: Monday, 07 February, 2005 6:05 PM
> > To: Group Study
> > Subject: eui-64 option - I think I got it
> >
> >
> > Hey guys,
> >
> > I went back to my Syngress book on ipv6 to see if I could figure out
when
> I
> > needed to use the eui-64 option
> >
> > when configuring an ipv6.
> >
> > Here's my conclusion:
> >
> > It's optional (unless the lab says otherwise).
> >
> > If you want - for whatever reasons - to assign all 128 of the
> > address
you
> > can
> > do so.
> >
> > For example, below the least significant bit (bit 128) is 1.
> >
> > Rack1R1(config-if)#ipv6 address 2001:157:1:14::1/64
> > Rack1R1(config-if)#do sh ipv6 int e0/0 Ethernet0/0 is up, line
> > protocol is up
> > IPv6 is enabled, link-local address is FE80::2D0:58FF:FE6E:B720
> > Global unicast address(es):
> > 2001:157:1:14::1, subnet is 2001:157:1:14::/64 <-- unicast
> > address doesn't include mac addr
> > Joined group address(es):
> > FF02::1
> > FF02::2
> > FF02::1:FF00:1
> > FF02::1:FF6E:B720
> > MTU is 1500 bytes
> > ICMP error messages limited to one every 100 milliseconds
> > ICMP redirects are enabled
> > ND DAD is enabled, number of DAD attempts: 1
> > ND reachable time is 30000 milliseconds
> > ND advertised reachable time is 0 milliseconds
> > ND advertised retransmit interval is 0 milliseconds
> > ND router advertisements are sent every 200 seconds
> > ND router advertisements live for 1800 seconds
> > Hosts use stateless autoconfig for addresses.
> > Rack1R1(config-if)#
> >
> > However, if I want - for whatever reasons - to have the router
> > assign
the
> > least significant 64 bits,
> > I could just add the eui-64 option to the end of the address command.
> >
> > Rack1R1(config-if)#no ipv6 address 2001:157:1:14::1/64 <-- remove
> previous
> > address
> > Rack1R1(config-if)#ipv6 address 2001:157:1:14::/64 eui-64
> > Rack1R1(config-if)#do sh ipv6 int e0/0 Ethernet0/0 is up, line
> > protocol is up
> > IPv6 is enabled, link-local address is FE80::2D0:58FF:FE6E:B720
> > Global unicast address(es):
> > 2001:157:1:14:2D0:58FF:FE6E:B720, subnet is 2001:157:1:14::/64
> > <--unicast addr includes mac addr
> > Joined group address(es):
> > FF02::1
> > FF02::2
> > FF02::1:FF6E:B720
> > MTU is 1500 bytes
> > ICMP error messages limited to one every 100 milliseconds
> > ICMP redirects are enabled
> > ND DAD is enabled, number of DAD attempts: 1
> > ND reachable time is 30000 milliseconds
> > ND advertised reachable time is 0 milliseconds
> > ND advertised retransmit interval is 0 milliseconds
> > ND router advertisements are sent every 200 seconds
> > ND router advertisements live for 1800 seconds
> > Hosts use stateless autoconfig for addresses.
> > Rack1R1(config-if)#
> >
> >
> > Do I have this right?
> >
> > Thanks for all your feedback. Tim
> >
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