Networking
What is IP transit?
Transit is a paid service in which one network carries another network's traffic to the rest of the internet. Multiple diverse transit providers is what keeps a network reachable when one upstream has an outage. OnionVPS buys transit from Cogent, Lumen, Arelion, GTT and Telia.
Why IP transit matters
Multiple diverse transit providers is what keeps a network reachable when one upstream has an outage. OnionVPS buys transit from Cogent, Lumen, Arelion, GTT and Telia.
IP transit in practice
When you run a server, IP transit is the contract your upstream sells you: your packets leave their network and reach the rest of the internet. You would look at your BGP sessions and your provider's routing table. If you have a single transit provider, an outage there takes you offline. The cost of getting it wrong is downtime — and with 99.99% uptime SLA, you might get credits, but your users still feel the outage.
What people get wrong about IP transit
People assume a server with unmetered bandwidth has transit included and therefore unlimited reach. Correction: unmetered bandwidth is about data volume, not path diversity. Your traffic still rides a specific set of transit providers. If that single upstream fails, you are unreachable regardless of how many gigabytes you can push.
IP transit — common questions
Why do I need multiple transit providers?
One transit provider is a single point of failure. If that provider has an outage, your traffic stops. Multiple diverse providers keep your network reachable when one upstream fails, which is why OnionVPS buys transit from five providers.
Does IP transit affect my latency?
Yes. The path your packets take depends on which transit providers are used and how they route. Different providers have different peering and backbone paths. You can measure latency and adjust routing, but you are limited by the transit choices your host makes.
More from networking
- ASN
- An ASN identifies a network that controls its own routing policy and announces its address space to the global routing table via BGP.
- BGP
- BGP is the protocol that autonomous systems use to exchange routing information and decide how traffic crosses the internet.
- IXP
- An IXP is a shared physical facility where networks interconnect directly rather than paying a transit provider to carry traffic between them.
- Peering
- Peering is a direct interconnection between two networks that exchange traffic with each other without paying a third party to carry it.
- Anycast
- Anycast announces the same IP address from several locations at once, so each user is routed to the nearest instance by BGP.
- IPv6
- IPv6 is the current version of the Internet Protocol, using 128-bit addresses to replace the exhausted 32-bit IPv4 space.
- Reverse DNS
- Reverse DNS maps an IP address back to a hostname through a PTR record, the inverse of a normal DNS lookup.
- Port 25
- Port 25 is the TCP port used for server-to-server SMTP mail delivery.