IPV6 link local

orange_badger

hi

im currently reading the offical cert guide for icnd 2 third edition and it seems to be so brief especially on link local addresses . Ive also checked my laptops link local address and it looks to be in a complete different format making use of a "%"

can anyone please point me in the direction of a good link or any good books which explain ipv6 and its implementation in home and business to a decent level

any help would be appreciated thanks

iamme4eva

I just googled it for you, as I've never heard of it. "percent sign in ipv6 address" throws up loads of results.

[h=2]Link-local addresses and zone indicesURL="http://www.techexams.net/w/index.php?title=IPv6_address&action=edit&section=34"]edit[/URL[/h]Because all link-local addresses in a host have a common prefix, normal routing procedures cannot be used to choose the outgoing interface when sending packets to a link-local destination. A special identifier, known as a zone index,^[7] is needed to provide the additional routing information; in the case of link-local addresses, zone indices correspond to interface identifiers.
When an address is written textually, the zone index is appended to the address, separated by a percent sign (%). The actual syntax of zone indices depends on the operating system:

• the Microsoft Windows IPv6 stack uses numeric zone indexes, e.g., fe80::3%1. The index is determined by the interface number;
• most Unix-like systems (e.g., BSD, Linux, Mac OS X) use the interface name as a zone index: fe80::3%eth0.

Zone index notations cause syntax conflicts when used in uniform resource identifiers (URI), so the '%' character must be escaped via percent-encoding^[35]: http://[fe80::3%25eth0]

That's from Wikipedia - while not necessarily the most reliable source, I read it on a few other sites too. https://en.wikipedia.org/wiki/IPv6_address#Link-local_addresses_and_zone_indices

orange_badger

yeh same no mention of it in the book think im gonna have a dig round amazon for some concrete material thanks for the link

iamme4eva

For what it's worth, I got through my CCNA and CCNP R & S without ever hearing about it!!! I like questions like this - they make me learn too.

I'm sure if you spend a few minutes searching you'll find some decent articles about it. There's a lot of good stuff out there.

NetworkVeteran

yeh same no mention of it in the book think im gonna have a dig round amazon for some concrete material thanks for the link

While you will find many routing & switching books that describe link-local addresses in detail--I recommend "IPv6 Essentials", which is up-to-date and aimed at the CCNA level--you won't find many describing the "%" zone index.

That's because this appears to be mostly a Windows/Linux/end-system thing. The zone index is not something sent over the wire, but rather states in ping and display commands what interface a link-local address is associated with. In IOS/JunOS/intermediate-systems, this is usually made clear through a combination of placement in show commands and a requirement to provide the outgoing interface in ping commands. Still, an interesting observation backed up by RFC 4007! Thanks for sharing.

iamme4eva

NetworkVeteran wrote: »

Still, an interesting observation backed up by RFC 4007! Thanks for sharing.

Nice RFC reference. Hope you had to google that aren't you aren't a walking RFC reference library! Every day is a school day...