Hi Nick, On 15/03/12 16:44 , Nick Hilliard wrote:
Hi Romeo,
thanks for the comprehensive replies, both here and on the blog.
And likewise, thanks for the discussion. No doubt more people on the list share your questions. :)
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.
In your example below, where the node peers with all parties on the peering lan, I would expect it to have a noticeable impact. Unless the IXP has no more than two connected members. ;-) But I admit to not having any hard numbers on this at the moment. FYI, the K-root 'hosted' solution does not involve virtualisation.
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.
Interesting. Thanks for that suggestion. We will certainly look into this to see if/how we can use this to improve the fit of our model for IXP's. However, I don't expect that we could support this on the short term.
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.
That may indeed happen, depending on path length over the transit of course. However, IXP participants may chose to prefer the local route over the transit route to still get that full benefit. Thanks for your comments. Our proposed model is targeting the vast majority of prospective hosts that have approached us, generally service providers. The IXP scenario is somewhat of a corner case. We will use your input to see how we can improve the model to also fit IXP's better. We already discussed this with some other IXP's as well and I propose that we discuss this a bit further, off list, to see how we might better address the IXP requirements. Kind regards, Romeo
Nick