Re: Same global address on Multiple Interface of an IP6 node

["Todd T. Fries" <todd@xxxxxxxxx>]

I understand there are tricks for faster thoroughput on IPv4 with regards
to multiple interfaces (network cards) and a single IP address.  Say,
two 100mbit cards plugged into the same 100mbit switch.  Is this `trick'
available with IPv6 in any fashion?
-- 
Todd Fries .. todd@fries.net


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(last updated 2003/03/13 07:14:10)

Penned by Roy Brabson on Thu, Jul 24, 2003 at 08:58:46AM -0400, we have:
| > Can a single global address (say 2222::1111) be configured on multiple
| > interfaces of a single ip6 node.
| 
| Yes, it can.  There are a few ways to accomplish this.  If all the 
| interfaces are on the same lan, then you could have a "primary" and a 
| "backup" interface.  If the interfaces are on different lans, you can run 
| a dynamic routing protocol and advertise the address as being reachable 
| through each physical interface on a node.  In this case, the address 
| isn't really configured on the multiple interfaces per-se (you instead 
| have a "virtual" interface which is assigned the IP address), but the 
| result is any interface on the node may be used.  There are other methods 
| which may be used as well.
| 
| > If so is there any specific purpose for doing that ??
| 
| Redundancy.  If one interface goes down, traffic will automatically switch 
| to the another interface without disrupting existing connections.
| 
| > What about link-local address, how would it be used, if single link 
| local
| > address is configured on multiple interface of a same node.
| 
| I'm not sure it is particularly useful.  Link-local addresses are really 
| intended to be used for bootstraping, configuration discovery, route table 
| maintenance, and the like.  Most, if not all, of these protocols work on a 
| per-interface basis.  I suppose it could allow an interface to act as a 
| "hot standby" for another interface, automatically switching over if the 
| primary interface fails.  But this would only work if the interfaces are 
| on the same physical lan.  If they are on different lans, then the two 
| interfaces are in different link-local scope zones and are treated as 
| unique addresses.
| 
| Roy
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