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Re: shim6 (was Re: IPv6 news)

  • From: Joe Abley
  • Date: Fri Oct 14 15:22:20 2005 
On 14-Oct-2005, at 14:48, David Conrad wrote:


On Oct 14, 2005, at 7:57 AM, Joe Abley wrote:
The big gap in the multi-homing story for v6 is for end sites, since those are specifically excluded by all the RIRs' policies on PI addressing right now. Shim6 is intended to be a solution for end sites.
Since shim6 requires changes in protocol stacks on nodes, my impression has been that it isn't a _site_ multihoming solution, but rather a _node_ multihoming solution. Is my impression incorrect?
There is no shortage of rough corners to file down, and I am behind on my shim6 mail, but the general idea is to let end sites multi-home in the "bag-o-PA-prefixes" style and let the nodes within that site use their multiple globally-unique addresses (one per upstream, say) to allow sessions to survive rehoming events.

Are you suggesting that something else is required for ISPs above and beyond announcing PI space with BGP, or that shim6 (once baked and real) would present a threat to ISPs?
If my impression is correct, then my feeling is that something else is required. I am somewhat skeptical that shim6 will be implemented in any near term timeframe and it will take a very long time for existing v6 stacks to be upgraded to support shim6. What I suspect will be required is real _site_ multihoming. Something that will take existing v6 customer sites and allow them to be multi-homed without modification to each and every v6 stack within the site.
For end sites, that's a wildly-held opinion.

For ISPs, it's not required, since ISPs can already multi-home in the manner you describe, using PI addresses and BGP.


Joe