Hi Romeo, thanks for the comprehensive replies, both here and on the blog. On 12/03/2015 09:29, Romeo Zwart wrote:
There are two drivers for that. We receive many requests from prospective new K-root hosts. We have considered how to respond to this demand from the community. This made us propose this smaller footprint server, enabling a wider variety of hosts at a lower cost. So, one driver for changing the BGP routing model, is in the simplified hardware. We prefer the single server to spend it's time on answering DNS queries, rather than spend its cycles on routing BGP.
mmm, depends how it's configured. E.g. if you have the device directly connected with a single o/s, bare-metal installation, it will make almost no difference. If you're using the hardware as a hypervisor, then yes there will be a performance impact but it can easily and cheaply be mitigated by adding an extra core or two and assigning those cores to the virtual router.
The second driver is that we spend a relatively large amount of engineering time on peering management for each instance. In the new model that factor is obviously reduced a lot, which allows us to scale the number of instances and achieve a finer grained distribution without a large increase in management and engineering effort.
Peering management is an issue that IXPs are painfully aware of and we've been doing a lot of work on this in the last 6 months. There's a new json formatted ixp participant data export schema which will allow you to import ixp data from multiple IXPs into your own internal systems. This format is being deployed across multiple IXPs. Once you have that data in your systems, it should be easy enough to use it to automatically configure IXP routers (assuming normal intermediate checks and param validation, etc). As you have an open peering policy, you could even do stuff like configuring bgp sessions to all ixp participants by default, but in passive mode. This would allow IXP participants to connect to you at their leisure. More at: https://github.com/euro-ix/json-schemas
We will discuss with hosts how they propagate the K-root prefix on a case by case basis. Some may prefer to distribute only locally, others may propagate globally. We expect of course that they tune this according to local capacity. We will monitor, using for example RIPE Atlas and DNSMON, the actual impact on K-root reachability for end users and work with the local hosts to optimize routing where needed.
I mentioned the side effect of this in a blog posting, namely that this will cause the k root BGP network distance to appear to be the same as transit. This means that in many cases the ixp instance will not be preferred and the ixp participants will not get the full benefit of having a nearby k root instance. Nick