[afnog] Survey: Collecting African IXP Colocation Data for research purposes (Slight changes in the survey)

[Roderick]

Thank you so much Nishal, 

Well noted. 

Roderick. 

On Feb 29, 2016, at 8:57 PM, Nishal Goburdhan <nishal at controlfreak.co.za> wrote:

> On 1 Mar 2016, at 4:13, Roderick wrote:
>> On Feb 29, 2016, at 4:45 PM, Nishal Goburdhan <nishal at controlfreak.co.za> wrote:
>> 
>> Ok I see. This might happen. However, if it does A can infer that B is peering with C (C is not peering with A but is present at the IX). And similarly C can infer that A is peering with B.
> 
> A can infer all it wants;  if B is operating a well run network, it will not change A’s view of the network.
> my point was that your premise of 3 networks, and hence there will always be two peers to each, is incorrect, even in start-up IXPs.
> 
> note:  i’m not commenting on best practice;  i’m simply trying to get you to see that there are other things that you have not counted for, in your model.
> 
> 
>> Could you please tell me how often 2 ASes in the region exchange part of their network prefixes via an IXP although the rest is operational?
> 
> quite often actually.  what usually happens is:
> * engineer A installs a peering router and connects to the domestic IXP
> * to achieve some traffic engineering, engineer B advertises a more specific prefix to the transit operator, but forgets to do the same to the domestic IXP
> * some sort of asymmetric routing happens
> 
> or ..
> 
> * network gets new address block/client
> * network does not advertise new network block to the IXP
> 
> or ..
> …
> 
> there are a few operators here that routinely complain on various IX lists, about inconsistent announcements that make the IX is less effective that it should be.  perhaps they’ll speak up with real world data for you    :-)
> 
> 
>> Sure. (PS: the *academic world* finds analyzing randomly collected measurements data more accurate than looking on the traffic graph published on the website ;) )
> 
> IANAA.    :-)
> and, for operators, what’s in the network, trumps what’s in some textbook.
> 
> —n.