I find selling combined "Internet" as International Transit bad; see below. On 12/12/14 14:05, Dave Mill wrote:
So, as an attempt to summarise the replies somewhat.
We should:
-Treat all IXes as equal LocalPref wise
So long as your traffic sinks (customers) are inside NZ, then yes :-)
-Optional: prepend an AS once on routes learnt from AKL-IX so it matches path length with Citylink run IXes
Right now, the AS-path for ISPs on Vocus via AKL-IX will be [Vocus],[ISPX] and the AS-path via APE will be [APE],[ISPX] - presuming 'ISPX' peers with APE and doesn't peer with AKL-IX. This sucks a bit, because traffic on your network could take Vocus on AKL-IX to reach ISPX since the AS-path length is the same. I suggest ISPs prepend once to Vocus if they are using their 'combined' International service to avoid that. The same goes for any other ISP who sells an 'internet' product (combined) as an International Transit product.
-Do further ASPath length mangling if you wish to prefer one IX over another (but probably only vary the path by +/- 1 AS)
You can't do anything of the sort. Path-stuffing APE will result in pain as traffic from other ISPs to you jumps from their domestic APE peering to their paid Vocus service because the path is now shorter. Locally preferring AKL-IX means your routers will use routes provided via Vocus into the AKL-IX. Again, using those ISPs paid connectivity to Vocus. You *could* LPREF AKL-IX and then reject routes from providers who sell combined Internet as transit. But that involves knowing who they are. Vocus is just one. I assume your traffic would then take APE, if that's your next highest LPREF.
Vocus international customers should:
-Use an appropriate Community to achieve AS path prepending on their advertisements by Vocus to the various IXes so as to not attract domestic traffic in their international tubez.
This won't work if someone LPREFs AKL-IX. The longer path offered by Vocus to AKL-IX will be preferred because LPREF comes first. Vocus really, really need to offer do-not-advertise on their combined product. Tim