v6 & DSL / Cable modems [was: Private use of non-RFC1918 IP space (IPv6-MW)]

Sun Feb 8 01:56:28 UTC 2009

Bill Stewart wrote:
> That's not because it's doing dynamic address assignment - it's
> because you're only advertising the aggregate  route from the
> BRAS/DSLAM/etc., and you can just as well do the same thing if you're
> using static addresses.  
Customers can land on one of a fleet of large BRAS across multiple POPs 
in a geographic region so that a failure of one piece of equipment or 
POP doesn't cause an outage.   If I want to run a hint of redundancy 
then I need to propogate statics out of the POP itself.  There are 
corners that can be cut but none seem to fit into the kind of redundancy 
we like.   Unlike a most BGP routes DSL circuits tend to go up and down 
a lot, this adds to convergence time and CPU load on the router. 

My issue is not basic network design skills.  My issue is that customers 
have indicated that they feel statics are a given for IPv6 and this 
would be a problem if I went from tens of thousands of statics to 
hundreds of thousands of static routes (ie. from a minority to  all).   
Even injecting statics into iBGP rather than an IGP I feel would add 
considerably to the load routers face and give a big hit in the event of 
failure.  (We already have a class of customer with statically assigned 
addresses or ranges).

The indication so far seems to be that on this list at least people 
don't see IPv6 statics for all as the general option.  This gives me a 
bit more hope.

MMC

-- 
Matthew Moyle-Croft - Internode/Agile - Networks
Level 4, 150 Grenfell Street, Adelaide, SA 5000 Australia
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