Public IP / IP Transit / IP Peering / ASN / Internet Exchange

Typically, the terms 'transit' and 'peering' are used when routes are exchanged via BGP between ASNs.

If i subscribed to an ISP internet service and the IP range is allocated by the ISP - it is consider IP transit right ?

Usually, no, not unless you're exchanging routing information via BGP. If not, it would just be 'internet access'.

If i have an ASN number / owned and subscribed IP range from APNIC and i want to advertise this IP range through 2 different ISP provider - is this still consider IP transit ?

IP transit refers to the routes exchanged. If you buy IP transit from an ISP, you get all routes in the DFZ (Default Free Zone), so you can reach the entire internet.

If i have an ASN number / owned and subscribed IP range from APNIC and directly connected to an IX service - this will then be consider IP peering ?

Yes, if you setup BGP sessions with other networks at the IXP. With peering, you typically receive only routes to the peer's network and its downstreams. So unless you peer with every network (or an upstream of every network), you won't reach every network on the internet.

Why will one choose 3) over 2) ?

You don't, not unless you're a Tier 1 network. Only those networks are big enough to receive a full view of the DFZ via peering sessions.

Any other network needs transit to reach specific parts of the internet. It's impossible to receive a full routing table via peering otherwise.

You can add peering to IXP's for various reasons, for example to reduce latency, lower costs or reduce dependency on specific transits.

You've got the definitions mostly right, but the distinction usually comes down to who holds the routing table (BGP) and who pays whom.

Here is how we usually define these in the field:

1. ISP Allocated Range (PA Space)

If i subscribed to an ISP ... is it consider IP transit right?

No, this is usually just "Dedicated Internet Access" (DIA). In this scenario, you are a "stub" network. You don't have an ASN, and you aren't running BGP (usually). You are just a customer inside the ISP's network. They handle all the global routing for you. You are just pointing a default route to them.

2. Your ASN + Your IPs + Upstreams

is this still consider IP transit?

Yes, strictly speaking. If you have your own ASN and you are announcing your prefixes to two providers who carry your traffic to the rest of the world, you are buying IP Transit. You are "transiting" their network to reach the rest of the internet. This is a standard "Multi-homed" setup.

3. Your ASN + IX Connection

this will then be consider IP peering?

Yes. Connecting to an Internet Exchange (IX) and setting up BGP sessions with other members (like Google, Akamai, or other ISPs) is Public Peering.

As to your last question: "Why would one choose (3) over (2)?" You generally don't choose Peering instead of Transit. You use Peering to reduce your Transit.

If you only have Peering (Option 3), you can only talk to the other networks on that specific exchange. You cannot reach the rest of the random websites on the internet unless one of those peers sells you transit.

You add Peering to your mix because:

Cost: Peering at an IX is often cheaper per Mbps than Transit.

Performance: If you push a lot of traffic to a specific network (e.g., you are an ISP and your users watch a lot of Netflix), peering directly with Netflix at an IX is faster than sending that traffic up through your Transit provider and back down.

Summary: You need Transit (2) to reach the whole world (Global Table). You add Peering (3) to offload heavy traffic and save money/latency.