IP Transit London

IP Transit is a service that provides a network (known as an ASN) with access to the wider internet through another, usually much larger, network. It is commonly used by internet service providers, data centres, and large organisations that need reliable global connectivity. In a typical IP Transit setup, the customer pays for a certain amount of bandwidth (known as a CDR) and the provider carries their traffic to and from the rest of the internet, using BGP to decide the best paths. Unlike peering, which is usually limited to traffic exchanged between specific networks, IP Transit offers full internet reachability.

A committed data rate, often shortened to CDR, is the amount of bandwidth you agree to use and pay for as part of an IP Transit service. It represents the guaranteed level of capacity that your provider will make available to you at all times, regardless of how busy the network is. Your charges are typically based on this committed rate, with any traffic above it either billed separately or subject to agreed limits, depending on the contract. In simple terms, the committed data rate sets a clear baseline for both cost and performance, helping you plan capacity while ensuring consistent and predictable internet connectivity.

A Tier 1 network operates without needing to buy IP Transit, as it can reach every other network on the internet through settlement free peering alone. In contrast, a Tier 2 network peers with some networks but still relies on IP Transit to reach parts of the internet it cannot access directly. In practical terms, Tier 1 providers tend to have the widest global reach, while Tier 2 networks often combine peering and transit to balance cost, coverage, and performance. For customers, the main difference is that Tier 1 transit can offer very broad reach, whereas Tier 2 transit may be more cost effective but depends on upstream providers for full internet access.

The 95th percentile is a common way of measuring and billing bandwidth usage for IP Transit services. Your traffic is sampled at regular intervals, usually every five minutes, over the course of a month, and the highest five per cent of those readings are discarded. The next highest value is then taken as your billable usage. This approach allows for short bursts of higher traffic without significantly increasing costs, while still reflecting your typical peak usage. In simple terms, it gives you some flexibility to handle spikes while keeping billing fair and predictable.

An , usually referred to as an ASN, is a unique number assigned to a network that controls its own routing policies on the internet. In the context of IP Transit, an ASN identifies your network when traffic is exchanged with other networks using BGP. It tells the wider internet who you are and how your routes should be treated. Having your own ASN is important if you want more control over how traffic enters and leaves your network, rather than relying entirely on the routing decisions of your transit provider.

RPKI, or Resource Public Key Infrastructure, is a security framework used to help protect internet routing. In the context of IP Transit, it allows networks to verify that route announcements they receive are authorised by the rightful holder of the IP addresses involved. This helps prevent problems such as route leaks and accidental or malicious hijacks, which can disrupt traffic across the internet. For customers, using a transit provider that supports RPKI adds an extra layer of trust and stability to how traffic is routed to and from their network.

A BGP community is a tag that can be attached to routing announcements to pass extra information between networks. In the context of IP Transit, communities are often used by customers to influence how a transit provider handles their routes, such as controlling where routes are advertised or how traffic is preferred. They provide a simple and flexible way to apply routing policies without changing the underlying BGP setup. In practical terms, BGP communities give network operators more fine grained control over traffic behaviour while keeping day to day routing management straightforward.

A BGP MD5 password is a shared secret used to secure BGP sessions between two networks. In the context of IP Transit, it helps ensure that only authorised routers can establish a BGP connection with your transit provider, protecting against accidental or malicious session resets. Both sides configure the same password, which is checked when the session is set up and during communication. While it does not encrypt traffic, it adds a basic but effective layer of authentication that improves the overall stability and security of routing.

TTL Security is a feature designed to protect BGP sessions from unwanted or spoofed connections. It works by limiting how far BGP packets can travel, so only routers that are directly connected, or within a very short distance, can successfully form a session. If a packet arrives with an unexpected TTL value, it is simply dropped. This reduces the risk of remote attacks against BGP and adds another practical layer of protection to keep routing sessions stable and under control.

IP Transit provides a full connection to the global internet, allowing your network to exchange traffic with all destinations via a service provider’s backbone and peering relationships. It’s typically used by ISPs, content providers and larger networks that need to advertise their own IP space and manage routing using BGP. Dedicated Internet Access (DIA), on the other hand, is a simpler, managed service that delivers reliable internet connectivity for a single site, usually with fixed bandwidth and less control over routing. In short, IP Transit offers greater scale and control for complex networks, while DIA is designed for straightforward, business-grade internet access.