Re: [Autoconf] Autoconf addressing model

"Teco Boot" <teco@inf-net.nl> Thu, 05 March 2009 14:04 UTC

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From: Teco Boot <teco@inf-net.nl>
To: 'Alexandru Petrescu' <alexandru.petrescu@gmail.com>
References: <499F0BA7.90501@piuha.net> <49A7E58C.2020303@gmail.com> <007201c99903$c4182c80$4c488580$@nl><49A82E55.10208@gmail.com> <007b01c99911$907facf0$b17f06d0$@nl><49A8471E.6090506@gmail.com> <009501c99920$92154340$b63fc9c0$@nl><49A944FF.9000102@gmail.com> <003001c99b2c$a3fcf4a0$ebf6dde0$@nl><49AD5184.6080300@gmail.com> <000101c99c3c$3121a870$9364f950$@nl><49AD9760.3080909@gmail.com> <49AD98D4.3@earthlink.net><49AD9EA8.6040803@gmail.com> <49ADA17B.9040600@earthlink.net><49ADAF7C.1050509@gmail.com> <49ADB9FB.6050600@earthlink.net> <49AE3A3A.5000305@gmail.com> <7FB7EE0A621BA44B8B69E5F0A09DC76407B5D783@xmb-rtp-208.amer.cisco.com> <49AE9827.5090309@gmail.com> <7FB7EE0A621BA44B8B69E5F0A09DC76407B5D803@xmb-rtp-208.amer.cisco.com> <49AEBA6D.7030903@gmail.com> <7FB7EE0A621BA44B8B69E5F0A09DC76407B5DB1F@xmb-rtp-208.amer.cisco.com> <49AF97FA.70200! 07@gmail.com> <002201c99d76$017d4b20$0477e160$@nl> <49AFAA15.9! 060905@gmail.com> <003a01c99d8e$f47ba2f0$dd72e8d0$@nl> <49AFD85E.504030 1@gmail.com>
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Date: Thu, 05 Mar 2009 15:04:41 +0100
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Subject: Re: [Autoconf] Autoconf addressing model
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Hi Alex,


|> So the following topology is valid:
|>
|> +----------+                        +----------+
|> |          |fe80::1/64              |          |
|> |          +========================+          |
|> | router 1 |              fe80::2/64| router 2 |
|> |          |fe80::1/64              |          |
|> |          +========================+          |
|> |          |              fe80::2/64|          |
|> +----------+                        +----------+
|>
|> Agreed on this?
|
|Agreed.  But why /64?  An address is /128, and the link-local address'
|prefix is /10.

I used address-prefix format (RFC4291).

And RFC2464:

5.  Link-Local Addresses
   The IPv6 link-local address [AARCH] for an Ethernet interface is
   formed by appending the Interface Identifier, as defined above, to
   the prefix FE80::/64.

The 54 bits following 1111111011 are zero. There is little difference
between FE80::/10 and FE80::/64. On Ethernet, it is the latter.



|> I repeated the test with the link local addresses. Here also, I
|> experienced no problems. This is because there are two links with
|> exactly the same address pairs (an advantage to use same LL addresses
|> on all interfaces).
|
|Demonstrating the advantage of loopback0 vs eth0 would have implied that
|you start OSPFv3 on eth0 instead of loopback0 and that it would have
|crashed.

My routing protocols do not crash. I told you before.



|But even then, I'm sure there may exist OSPFv3 implementation which
|would not crash when running over eth0 and ifconfig down eth0.
|
|In this sense, if the loopback0 interface is a solution to crashing
|OSPFv3-over-eth0, then it is an implementation solution. Some
|implementations do, others don't.

You totally missed the point.



Teco.