>>>>> InuY4sha <(E-Mail Removed)> writes:
> Can a Link Local Address be routable? What ISO/OSI layer is a Link
> Local Address bounded to? L2 or L3?
Why this question sounds like a homework assignment, I wonder?
For the second part, a shared-media link layer (such as
Ethernet, even though it's more point-to-point these days)
generally employs some kind of addressing: as all the nodes
receive the message sent (the media is shared, remember?), there
has to be a way for the receiving node to determine whether the
message is targeted at it.
However, as the link layer has no knowledge whatsoever about
anything beyond its own link, the only addresses it may ever get
are the link local ones.
On the other hand, the /network/ layer covers a /network/ of
multiple links. It may, however, for some specific needs (such
as autoconfiguration) have to use some kind of “generic”,
predefined addresses, whose scope we, however, have to limit to
a specific link. To distinguish these addresses from the
network-wide addresses (which are the ones we've introduced the
network layer for in the first place) we call them “link local.”
As for the routing, it's sometimes stated that the network level
addresses are introduced to uniquely name all the nodes in the
network. It's not quite true — the Media Access Control
sublayer addresses (as per Ethernet) are already sufficiently
unique; and, IPv6 link local (and, sometimes, global) addresses
are derived from them. Think, however, of what a kind of
routing table it will require to support forwarding to such
addresses at the scale of Internet. Hopefully, this will allow
you to attain the enlightment.
--
FSF associate member #7257 Coming soon: Software Freedom Day
http://mail.sf-day.org/lists/listinfo/ planning-ru (ru), sfd-discuss (en)
Similar Threads
Linear Mode
