What is a Tier 1 network?

A Tier 1 network is an operator that reaches the entire internet purely through settlement-free peering, that is, without buying IP transit from anyone. A Tier 1 network pays no other network for reachability and takes no default route, because direct peering relationships with the other Tier 1 networks give it full reachability of the world. Tier 2 and Tier 3 are categories defined by contrast: they describe operators that must purchase some or all of their reachability as transit.

Tier 1, Tier 2 and Tier 3

The tier hierarchy is not a formal standard or a certification, but a widely used description of where a network sits in the global chain of interconnection. One criterion decides it: does the operator have to pay anyone to reach the rest of the internet? Tier 1 networks pay no such fee, because they exchange traffic with every other Tier 1 on a settlement-free basis and together form the core of the internet.

• Tier 1: full reachability purely through settlement-free peering, with no transit purchased and no default route.
• Tier 2: peers with many networks but buys some reachability (usually distant regions) as IP transit.
• Tier 3: connects to the internet almost entirely through paid transit, with little or no peering.
• The lines are blurry: most operators are Tier 2, and only a dozen or so networks worldwide hold Tier 1 status.

Settlement-free and the default-free zone (DFZ)

Settlement-free means neither party pays the other for the exchanged traffic, because both gain comparable value from the link. Tier 1 networks can operate without transit precisely because settlement-free peering ties them together in a full mesh, in which each one sees the prefixes of all the others. This connects to the idea of the default-free zone (DFZ): the set of routers that have no default route configured and make decisions solely from the full BGP table, which today holds close to a million IPv4 prefixes. The core routers of every Tier 1 network belong, by definition, to the DFZ.

Why the tier of your provider matters

The tier label is often abused in marketing, so look at the facts rather than the slogans. Tier 1 status alone does not guarantee the best route to every destination, because quality is decided by the actual topology, presence at the right exchanges and BGP policy, not by the name of the category. For most Polish operators the best strategy is multihoming on two or more independent transit providers, complemented by broad local peering. That setup gives short domestic paths and resilience to failures regardless of the provider's formal tier.

Where AS202520 SkyPass sits in this hierarchy

AS202520 SkyPass is not a Tier 1 network and does not claim that status, because we base global reachability on IP transit from several independent upstreams. Our strength is dense peering at Polish internet exchanges, including THINX, TPIX, WRIX and 1-IX. Through it, domestic traffic reaches its destination over the shortest local path instead of detouring through Western Europe. Multiple upstreams combined with dense peering give customers an effect close to direct access to the core: the full BGP table, low latency to networks in Poland and a predictable cost.