[192103] in North American Network Operators' Group
Re: nested prefixes in Internet
daemon@ATHENA.MIT.EDU (Owen DeLong)
Wed Oct 19 12:51:00 2016
X-Original-To: nanog@nanog.org
From: Owen DeLong <owen@delong.com>
In-Reply-To: <CAJx5YvG93ThGeBvFkpdh7eBsuTC+6qEJi_5C7d5o5ZjmmoXgiA@mail.gmail.com>
Date: Wed, 19 Oct 2016 11:50:48 -0500
To: Martin T <m4rtntns@gmail.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
Assuming that there is a PNI A<->C assumes facts not in evidence.
Owen
> On Oct 19, 2016, at 11:27 AM, Martin T <m4rtntns@gmail.com> wrote:
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> Hi,
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> I made a drawing of those two best solutions: =
http://i.imgur.com/7NQVgUH.png
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> As much as I understand, both solutions require no special changes
> from "ISP C". Only advantage of solution B over solution A, that I can
> see, is that at the time when link between "ISP C" and "ISP B" is up,
> the traffic from Internet towards "ISP B" prefers the "ISP C"
> connection.
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>=20
> In case the link between "ISP A" and "ISP B" goes down, then traffic
> from "ISP A" addressed to this /24 will use a private peering link
> between "ISP A" and "ISP C" so the transit costs are not an issue.
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> thanks,
> Martin
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> On Wed, Oct 12, 2016 at 1:58 AM, Owen DeLong <owen@delong.com> wrote:
>>=20
>>> On Oct 10, 2016, at 14:59 , Baldur Norddahl =
<baldur.norddahl@gmail.com> wrote:
>>>=20
>>>=20
>>>=20
>>> Den 10/10/2016 kl. 22.27 skrev Owen DeLong:
>>>> Not true=E2=80=A6 There are myriad reasons that the /24 might not =
reach a network peered with ISP-A, including the possibility of being a =
downstream customer of a network peered with or buying transit from =
ISP-A. In the latter case, not an issue, since it=E2=80=99s paid =
transit, but in the former (peered, not transit), again, ISP-A is =
probably not super excited to carry traffic that someone isn=E2=80=99t =
paying them to carry.
>>>>=20
>>>=20
>>> But ISP-A is in fact being paid to carry the traffic. Supposedly =
ISP-B has a paid transit relation to ISP-A. In the case the transit link =
is down ISP-A might have to transport the traffic through a less =
profitable link however.
>>=20
>> Which isn=E2=80=99t really in the agreement between ISP-B and ISP-A =
unless it was specifically (and unusually) negotiated.
>>=20
>> Also, you=E2=80=99re assuming that the leased space came with a =
transit agreement. In many cases, address leases don=E2=80=99t, so =
consider the additional scenario where ISP-B leases addresses from =
ISP-A, but has transit contracts with ISP-C and ISP-D but no connection =
at all to ISP-A.
>>=20
>>> I know that if ISP-A was my network I would be making money even =
with the transit link down. Yes I might have to transport something out =
of my network through one of my transits, but outbound traffic is in =
fact free for us because we are heavy inbound loaded.
>>=20
>> Yes, but it doesn=E2=80=99t help if it also came in on a transit =
link. Any traffic you both receive and transmit on transit costs you =
money pretty much no matter who you are.
>>=20
>>=20
>> Owen
>>=20
