* Why does IPV6 link local address advertised as /64?
@ 2008-11-12 4:49 Stephen Hemminger
2008-11-12 5:29 ` Matti Aarnio
2008-11-12 7:44 ` Rémi Denis-Courmont
0 siblings, 2 replies; 3+ messages in thread
From: Stephen Hemminger @ 2008-11-12 4:49 UTC (permalink / raw)
To: netdev
It seems to make more sense to have only the actual host (ie /128)
on the link-local address or is there some other purpose to
using a /64?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Why does IPV6 link local address advertised as /64?
2008-11-12 4:49 Why does IPV6 link local address advertised as /64? Stephen Hemminger
@ 2008-11-12 5:29 ` Matti Aarnio
2008-11-12 7:44 ` Rémi Denis-Courmont
1 sibling, 0 replies; 3+ messages in thread
From: Matti Aarnio @ 2008-11-12 5:29 UTC (permalink / raw)
To: Stephen Hemminger; +Cc: netdev
On Tue, Nov 11, 2008 at 08:49:06PM -0800, Stephen Hemminger wrote:
> It seems to make more sense to have only the actual host (ie /128)
> on the link-local address or is there some other purpose to
> using a /64?
The purpose of the link-local prefixes is not to report interface
physical address, but enable communication without yet having
full configuration in place - this enables ZeroConfig, DHCP6,
etc. mechanisms.
Consider Ethernet with link-local address, you can do peer-to-peer
communication there without global addresses by using MAC address
derived link-local address. Indeed the global prefix RA's are
link-local multicasts.
Furthermore, with links using _same_ /64 prefix and possibly varying
suffix, all applications using the link-local addresses must also
inform socket binding of the interface where it is to be applied to.
/Matti Aarnio
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Why does IPV6 link local address advertised as /64?
2008-11-12 4:49 Why does IPV6 link local address advertised as /64? Stephen Hemminger
2008-11-12 5:29 ` Matti Aarnio
@ 2008-11-12 7:44 ` Rémi Denis-Courmont
1 sibling, 0 replies; 3+ messages in thread
From: Rémi Denis-Courmont @ 2008-11-12 7:44 UTC (permalink / raw)
To: ext Stephen Hemminger; +Cc: netdev
On Wednesday 12 November 2008 06:49:06 ext Stephen Hemminger, you wrote:
> It seems to make more sense to have only the actual host (ie /128)
> on the link-local address or is there some other purpose to
> using a /64?
For the same reason that IPv4 link-local (169.254/16) addresses are /16 rather
than a /32. There are LINK-local addresses, not HOST-local addresses - you
must be able to talk to other nodes on the link with them.
--
Rémi Denis-Courmont
Maemo Software, Nokia Devices R&D
^ permalink raw reply [flat|nested] 3+ messages in thread
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2008-11-12 4:49 Why does IPV6 link local address advertised as /64? Stephen Hemminger
2008-11-12 5:29 ` Matti Aarnio
2008-11-12 7:44 ` Rémi Denis-Courmont
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