BGP peering + transit mix
Everything your fleet serves has to leave the building somehow. You always have the plain "open Internet" path — it is free and it is already there, but traffic wanders across whoever happens to be in the way before it reaches your customer. Buying transit gives you a steadier, watched path: someone is paid to carry your traffic and held to a promise about it. Direct peering means you run a cable straight to another network and skip the middle entirely — the fastest option, and the most expensive to keep lit.
You do not have to choose just one. Most facilities keep the free Internet path as a fallback, buy transit for the bulk of paid, reliable traffic, and add direct peering to the handful of networks where low latency actually wins a contract. The trade is always the same: cheaper paths wander and add delay; pricier paths are short and predictable. As your customers grow pickier about latency, the mix tilts toward transit and direct.
Detailed explanation
You announce your prefixes upstream over BGP4. Three peering kinds, mix-and-match: Internet (always present, cheapest, longest AS path, no SLA), Transit (paid, SLA-backed, mid-latency, the workhorse), Direct (cross-connect at a meet-me, single-AS hop, premium fixed cost). Each kind carries a latency multiplier on the peering record — the projection folds it into the customer-facing latency budget.
Cost and latency trade off per kind. Internet is free but adds the most hops and has no recourse when a transit provider mid-path congests. Transit buys you a watched path and an SLA. Direct collapses the path to one hop at the cost of a standing cross-connect. Latency-sensitive tenants push the mix toward Transit/Direct; cost-sensitive bulk egress can ride the free Internet path. PeeringMix below shows the current split.