IP transit is the service that connects networks to the global internet through an upstream provider. Understanding how it works helps you make informed decisions about connectivity, bandwidth, and routing for your infrastructure.
Publish date: 1/1/2026
Every time you load a website, send an email, or stream a video, your data travels through multiple networks before reaching its destination. But how does your network actually connect to the rest of the internet? That's where IP transit comes in.
If you're running servers, managing infrastructure, or just curious about how internet connectivity works behind the scenes, understanding IP transit is worth your time. It's the backbone service that lets networks communicate globally, and it plays a big role in performance, reliability, and cost.
IP transit is a service where one network (usually an Internet Service Provider) sells access to the global internet to another network. Think of it as buying a pathway to reach every other network on the internet.
When you purchase IP transit, you're essentially paying for bandwidth and routing capability. Your upstream provider (the transit provider) accepts your traffic and forwards it to its destination anywhere on the internet. They also deliver traffic from the internet back to your network.
This is different from a direct connection to a single service or network. With IP transit, you get access to the entire internet routing table, which contains routes to hundreds of thousands of networks worldwide.
The technical foundation of IP transit relies on BGP (Border Gateway Protocol), the routing protocol that makes the internet work.
Here's how the process typically unfolds:
Your network connects physically to a transit provider's router, usually through fiber optic cables. This connection might be at a data center, internet exchange point, or other network facility.
Once physically connected, you establish a BGP session with your transit provider. Through this session, you advertise your IP address space (your network prefixes) to them, and they advertise the full internet routing table to you.
When someone tries to reach your network from the internet, their traffic eventually reaches your transit provider, which forwards it to you. When you send traffic out, your transit provider receives it and routes it toward its destination, either directly (if they're connected to that network) or through their own upstream providers or peering relationships.
The transit provider essentially becomes your upstream connection to the internet. They handle all the complexity of reaching every network globally, maintaining relationships with other networks, and keeping routing tables updated.
Several technical elements work together to make IP transit function:
BGP announcements: Your network announces its IP prefixes to the transit provider, advertising that traffic for those addresses should be sent to you. The transit provider then propagates these announcements across the internet.
AS numbers: Each network that participates in BGP routing needs an Autonomous System Number (ASN). This unique identifier represents your network in the global routing system. Your transit provider uses their ASN, and you'll typically need your own if you're buying transit from multiple providers.
Physical connectivity: The actual network connection matters. This might be a cross-connect in a data center, a leased fiber line, or connectivity through an internet exchange. The capacity of this connection determines your maximum bandwidth.
Service level agreements: Transit contracts typically specify bandwidth commitments, uptime guarantees, latency targets, and support response times. These SLAs define what you're actually paying for beyond just the raw connection.
Understanding the difference between transit and peering helps clarify how internet connectivity works:
Transit is a paid service where you buy access to the entire internet. The transit provider takes responsibility for delivering your traffic anywhere and accepting traffic from anywhere for delivery to you.
Peering is a mutual agreement between two networks to exchange traffic directly, typically without payment. Networks peer when it's mutually beneficial, usually to reduce costs and improve performance for traffic between them.
Most networks use a combination of both. You might have transit for reaching the entire internet, plus direct peering relationships with networks you exchange a lot of traffic with (like content delivery networks or other large providers).
Transit providers themselves maintain extensive peering relationships. When you buy transit, you're indirectly benefiting from all of their peering agreements and upstream connections.
Transit services come in different configurations depending on your needs:
Full transit provides access to the complete internet routing table. This is the standard service most people mean when they talk about IP transit. You can reach any network on the internet through your provider.
Partial transit or regional transit connects you to specific geographic regions or network segments. This is less common but sometimes used for specialized scenarios or cost optimization.
Transit with DDoS protection includes traffic scrubbing and filtering to protect against distributed denial of service attacks. Many modern transit providers offer this as a standard feature or add-on.
Burstable transit allows you to pay for a baseline bandwidth commitment but temporarily burst above that limit when needed, paying only for the extra usage. This can be cost-effective for traffic patterns with occasional spikes.
Several factors should influence your decision when selecting transit providers:
Network quality and reach: Look at the provider's network topology, where they have points of presence, and what their connectivity looks like. Providers with extensive peering deliver better performance and often lower latency. You can check publicly available looking glass tools to see routing paths.
Bandwidth pricing and terms: Transit is typically sold as either committed bandwidth (you pay for a set amount whether you use it or not) or 95th percentile billing (you pay based on your usage, excluding the top 5% of spikes). Compare pricing models and understand the contract terms.
Redundancy requirements: Most networks buy transit from at least two providers for redundancy. If one provider has issues, your traffic can reroute through the other. This is called multihoming, and it's standard practice for anything mission-critical.
Support and SLAs: When network issues happen, responsive support matters. Check what support channels are available, typical response times, and whether they have 24/7 coverage.
Once you've selected a provider, the implementation process typically follows these steps:
First, you'll need physical connectivity established. This might involve ordering a cross-connect in a data center or arranging for fiber installation. The transit provider will specify what type of interface they support (typically 1G, 10G, 100G, or higher Ethernet).
Next comes the BGP configuration. You'll need to configure your router to establish a BGP session with the provider's router. This involves exchanging ASN information, setting up authentication, and configuring route filters.
You'll then start announcing your IP prefixes to the transit provider. They'll verify that you're authorized to announce those addresses (usually through registry checks) before accepting and propagating your routes.
Testing and verification come next. Send test traffic, verify routing paths using tools like traceroute, and confirm that traffic flows in both directions properly.
Finally, monitor performance and adjust as needed. Watch bandwidth utilization, latency metrics, and routing behavior to make sure everything performs as expected.
IP transit pricing varies widely based on location, volume, and provider. Here's what to expect:
Pricing is typically quoted per Mbps per month. In major internet hubs such as New York and London, strong competition and high-capacity infrastructure have driven bulk pricing to the low end of the range, often well under $1 per Mbps at scale, while prices in less connected markets remain significantly higher.
Most transit is sold on a committed bandwidth basis, meaning you pay for a fixed amount of capacity regardless of actual usage. For example, a 1 Gbps commit means you’re billed for 1,000 Mbps each month.
95th percentile billing is also common. This model measures usage in five-minute intervals over a month, discards the top 5% of readings, and bills on the remaining peak, allowing for short traffic spikes without paying for full peak capacity.
Minimum commit levels are standard. Smaller commitments, often under 100 Mbps, tend to be less cost-effective due to operational overhead and may carry higher per-Mbps pricing or minimum charges.
Setup fees may apply, particularly for new physical connectivity, and typically cover provisioning, configuration, and administrative costs.
Different types of organizations use IP transit for various purposes:
Web hosting and cloud providers need transit to connect their customers' applications and websites to internet users worldwide. They typically purchase large amounts of bandwidth across multiple locations.
Content delivery networks use transit to reach eyeball networks (residential ISPs) that their content needs to be delivered to, though they also rely heavily on peering for cost efficiency.
Enterprise networks often buy transit for their data centers or as backup connectivity for critical sites. This supplements private network connections and provides internet access for services.
Internet exchanges and data centers sell transit as a service to their customers, becoming transit providers themselves by reselling or aggregating connectivity from larger upstream providers.
Small hosting companies and individuals running dedicated servers or colocation might purchase smaller amounts of transit for their infrastructure needs.
IP transit is the wholesale service that networks buy to connect to the internet, while internet access typically refers to end-user services like residential or business broadband. Transit assumes you're operating network infrastructure and announcing your own IP space through BGP, whereas internet access is a consumer service where the ISP handles all routing.
Not always, but it's common for networks buying transit from multiple providers. A single transit provider can announce your IP space on your behalf, but having your own ASN gives you more control and flexibility, especially for redundancy scenarios. If you're planning to multihome or do any advanced routing, you'll want your own ASN.
Start by measuring your current peak traffic levels and projecting growth. Many networks begin with commitments in the 100 Mbps to 1 Gbps range and scale up as needed. It's better to start conservative and upgrade than to overpay for capacity you won't use. Look at your 95th percentile usage over time to understand real requirements.
Yes, and it's recommended for redundancy. This is called multihoming. You'll announce your IP prefixes through multiple transit providers simultaneously, and internet routing will automatically use the best available path. If one provider has issues, traffic reroutes through the others. This does require your own ASN and more complex BGP configuration.
If you have only one transit provider, you lose internet connectivity until they restore service. This is why most production environments use multiple transit providers. With proper multihoming configuration, traffic automatically shifts to working providers within seconds of detecting an outage.
IP transit is what actually connects networks to the global internet. Whether you're running a few servers or managing large-scale infrastructure, understanding transit helps you make better decisions about connectivity, costs, and reliability.
The right transit setup depends on your specific needs. Consider your bandwidth requirements, budget, redundancy needs, and where your users or customers are located. Most scenarios benefit from multiple transit providers for redundancy, proper BGP configuration, and ongoing monitoring to catch issues early.
Thanks for reading! If you're looking for reliable network connectivity, xTom provides IP transit services with competitive pricing, extensive peering relationships, and presence in multiple global locations. We also offer dedicated servers, colocation, and a full range of infrastructure services. For scalable compute needs, V.PS delivers NVMe-powered KVM VPS hosting that's production-ready from day one.
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