[j-nsp] Core network design for an ISP

[Saku Ytti]

On 27 March 2016 at 13:20, Mark Tinka <mark.tinka at seacom.mu> wrote:
> I don't like 6PE due to fate-sharing, but I know a lot of people run it
> because it reduces workload.

I understand this argument, but I feel it's opposite. Let's assume
there is 5% chance of failure to occur in some time frame, i.e. 95% of
not occurring. If your control-plane depends on two separate instance
working to produce services then you have only 90% chance of failure
not occurring, i.e. you reduced service availability by deploying more
features.

Now you could argue that sure, you maybe have slightly higher chance
of failing one of them, but you have much lower chance of failing all
of them at same time, that may be true. But for me, having IPv6 up if
IPv4 is down is 0 value. The control-plane example you have is
non-issue, because I'm going to need OOB to RS232 anyhow.

I would decouple my services from my control-plane signalling. And
crucially in this particular example, if I'm running MPLS, native IPV6
is not an option, I need labeled paths to have same IPv4 and IPv6
behaviour, RSVP applicability, convergence, BGP free core etc. Only
reason I would ever consider native IPv6 is if I'm also doing IPv4
lookups in core.


-- 
  ++ytti