[af-ix-discuss] Renseignements, Interconnexion de deux POP

[nishal at ispa.org.za (Nishal Goburdhan)]

On 4 Jan 2018, at 15:07, Benny.MBOKO at arpce.cg wrote:

> Bonjour ? tous et tous mes v?ux les meilleurs,
>
> Je viens vers vous pour un peu plus de lumi?re sur l?interconnexion 
> de 2 POP.
> Comment peut-on interconnecter deux Points de Pr?sence d?un IXP 
> sachant que chaque POP a ses propres ressources (ASN et IP)
> Les ressources de management de chaque POP interviennent-elles dans 
> cette interconnexion ?
> Quelles sont les ?tapes ? franchir et quelles sont les pr?requis ?
> Merci pour votre coup de pouce.
>
> Cordialement
> Benny Sh?rif MBOKO OTOKA
> Administrateur r?seau et syst?me
> Au Service du tr?s haut d?bit
> [cid:image001.png at 01D04223.BE54C720]
> Immeuble ARPCE ,91 bis Avenue de l?amiti?
> Centre-ville-Brazzaville-Congo BP : 2490
> T?l mobile : (+242) 06 653 29 38/044525539
> T?l bureau : (+242) 05 510 72 72
> Site internet : www.arpce.cg<http://www.arpce.cg/>
> Email : Benny.MBOKO at arpce.cg<mailto:Benny.MBOKO at arpce.cg>


hi benny,
you had sent this message to the mailing list owner in error.  i?m 
redirecting this to the mailing list, (and i took the liberty of 
replying as well :-)

happy 2018 to you too!

it is not a good idea to interconnect internet exchange points.  it is 
better to allow internet exchange points to run and develop 
independently.  over time some internet exchange points may fail.  
that?s not necessarily a bad thing, and simply shows how the market, 
or policy, changes in a region.  in cases where you hear of IXPs 
interconnecting, it is generally the same IXP that has multiple PoPs 
within a city.  this usually happens when there are multiple colocation 
facilities in the city, and when peering participants (ie. the networks 
that want to peer) want to be able to connect to the same IX fabric, but 
from different facilities.

but, even this is not easy to accomplish, since the IXP administrator 
would have to take the effort of building infrastructure to connect 
across the city.  this infrastructure will not be free, and now places 
the burdens of capital expenditure (ie. equipment) and operational costs 
(ie. payments to keep the fibre running) on the shoulders of the IXP 
admin.  generally, IXPs are non-profits that work to improve 
interconnectivity (and not ISPs that are working to make money) so, 
increasing the cost of the IXP?s operations is something that you 
always want to avoid!
artificially increasing the cost of running the IXP, means that you 
would need to find creative ways of funding this, and that would quickly 
distract you, the IXP administrator, from the basic operations of the 
IXP - which is to run a stable fabric!  so, even if you are thinking of 
building, or extending your IX to multiple sites, i?d strongly suggest 
doing this, *if, and only if*, the cost of the fibre between the 
different locations is very cheap, or free!
note the first very big constraint here - the cost.

i started with cost, since, it is important to realise what an IXP is 
meant to do.  a well-managed IXP will reduce the 
average-per-bit-delivery-cost (ABPDC) of the networks that connect to 
it.  ie.  peering makes the network cheaper to run.  if this is not 
true, networks will stop peering, and continue/start purchasing IP 
transit instead.  so, if you start to introduce costs into the IXPs 
operations, the IXP will have to find ways to fund this, and, that goes 
against the what is probably the first rule of the IXP - which is to 
make interconnection cheaper!
of course, the costs go beyond just the recurring costs of the 
connectivity between the locations;  as the IX operators, if you did 
decide to build a distributed exchange, you?d need to have a 24x7 NOC 
to manage this.  and you can?t have just a single person, so that 
means staff costs, HR costs, etc.  all of which needs to be funded, and 
all of which makes it even more difficult to get networks to the IX to 
start.

there are other reasons as well;  if you do go ahead, and make this 
happen, then your participants - networks that would otherwise be 
peering - may complain that you are competing with them for 
transmission, and may withdraw from your IX.  that is *absolutely* to be 
avoided, since a network removing itself, is never a good thing for the 
peering environment.  and, in the long term, this is a direct 
disincentive to invest in telecoms infrastructure by the private sector; 
  infrastructure, which otherwise, would lead to more competition, lower 
pricing, and a more stable overall network.

i?ve mentioned three reasons, and explained just one in some detail.  
but i?m hoping you start to see that this isn?t a good idea!

there only a few niche caches where an IXP interconnects directly with 
another;  these *always* come with limitations;  rules like you are not 
allowed to use more than X %bandwidth, etc.  in the long run, this 
situation does not scale, and is generally avoided.  of the more than 
500 IXPs globally today, there are fewer than ten cases where this 
happens, and i would strongly encourage you to not follow this model.  
interconnecting IXPs may sound like a grand idea, and it serves a 
short-term political goal, but at a practical, and long-term economic 
level, it?s quite a disastrous thing to do to your economy.

there are many cities in the world that have multiple IXPs, that do not 
interconnect with each other.  multiple IXPs in a city work best, when 
they are considered separate (ie. different infrastructure) and 
generally only work well, when there?s already a rich mesh of 
interconnectivity.  in other words, get an IXP up and running;  try to 
get as many participants connected and peered, and when these 
participants start to feel like there is a need for resiliency, then 
it?s a good idea to consider getting another IXP up within the same 
city.   it?s a *terrible* idea to start two competing IXPs from day1, 
as this will likely fragment the peering market, and that?s something 
that you want to avoid at all costs.

i?ll pause here to give other list folk a chance to express their 
opinions, but i?m happy to explain this in greater detail if 
necessary.   ;-)

?n.