[lacnog] Problemas en torno a SLAAC/DHCPv6-PD (nuevo IETF I-D)

Fernando Frediani fhfrediani en gmail.com
Jue Ene 31 10:42:05 -02 2019

Hello Fernando.

Thanks for sharing this with us.

This behavior is quiet common in some scenarios and causes, 
unfortunately, different views from users and some technical people 
believing that "IPv6 is making Internet slower".
I had the impression, in some occasions, that old IPv6 addresses hang in 
devices were more a OS issue than a SLAAC, but what you describe in the 
Draft makes sense.

One thing I have sympathy is, where possible, allocate always stable 
prefixes so the same Prefix to the same user using the 
Delegated-IPv6-Prefix and Delegated-IPv6-Prefix-Pool in RADIUS and 
therefore eliminating this issue, easing the user identification should 
you are required by the Estate and reducing the amount of necessary log.

Reading the Draft I am wondering here how and if this mechanism could 
also be applicable for something I have put here a while ago: two CPEs 
in the same Layer 2 advertising their addresses with different 
Priorities and one the one with higher priority looses connectivity to 
the upstream immediately deprecate its addresses announced to the LAN 
letting the less priority CPE addresses be the ones used by devices to 
go out to the internet making the IPv6 failover seamless in Home/SOHO 
scenarios where BGP is not available or suitable.

Best regards
Fernando Frediani

On 31/01/2019 08:54, Fernando Gont wrote:
> Estimados,
> Hemos publicado un nuevo IETF I-D que discute e intenta proveer una
> solución a un problema asociado a la interacción entre SLAAC y
> DHCPv6-PD: https://tools.ietf.org/html/draft-gont-6man-slaac-renum
> El Abstract dice:
>     A very common IPv6 deployment scenario is that in which a CPE employs
>     DHCPv6 Prefix Delegation to obtain an IPv6 prefix, and at least one
>     prefix from within the leased prefix is advertised on a local network
>     via SLAAC.  In scenarios where e.g. the CPE crashes and reboots,
>     nodes on the local network continue using outdated prefixes which
>     result in connectivity problems.  This document analyzes this problem
>     scenario, and proposes workarounds.
> Dada la proscripción :-) existente en determinados en entornos en
> relación al sentimiento maradoniano, el draft en cuestión incluye un
> "guiño" a la comunidad maradoniana. Al primero que lo encuentre y
> reporte por aqui (incluyendo algún enlace que explique/justifique el
> guiño en cuestión), lo invito una cerveza en el proximo evento de LACNIC.
> Saludos, y gracias!

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