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Key points
- Distance is only one factorBGP policy and upstream quality can matter as much as geography.
- Return path mattersClean traffic can enter through one path and return through another, creating asymmetry.
- Mitigation must be local enoughA scrubbing path that is too far away can protect availability while damaging experience.
Definition of the problem
The problem is that latency is often reduced to a marketing claim: “low latency”, “premium network” or “Europe optimized”. In reality, a packet path is the result of policy. A provider may be physically close but poorly connected to a user ISP. Another may be farther away but have a better route and less congestion.
BGP does not choose the lowest latency path by default. It chooses a route based on attributes and policy: local preference, AS path, MED, communities and provider decisions. That means two users in the same country can reach the same protected service through different paths.
Anti-DDoS adds another layer. Traffic may first be attracted to a mitigation PoP, filtered, then returned to the customer by tunnel or cross-connect. If the PoP is badly located or the return path is inefficient, the service remains online but feels unstable, especially for games and real-time applications.
Why it matters
Latency matters commercially because users do not care whether the route is technically elegant. They feel delay, jitter and packet loss. A FiveM player sees desync. A VoIP user hears cuts. An API customer sees timeouts. A hosting client blames the provider even if the issue is a transit path.
It also matters during attacks. Some providers route all protected traffic to a distant scrubbing center only when mitigation starts. That creates a sudden latency jump exactly when the customer is already under pressure. Better designs keep the mitigation path predictable and close to the natural route where possible.
For operators, latency is also a cost signal. A bad route can increase backbone usage, tunnel overhead and support tickets. Measuring latency only from the provider PoP is not enough; the useful measurement is from real user networks to the protected service and back.
Possible solutions
The first solution is to choose PoP locations close to the main user base and well connected to major networks. A PoP is useful only if the surrounding transit ecosystem is strong.
The second is route monitoring by ASN and region. Looking at average ping from one server is not enough. You need to know how traffic from Orange, Free, Bouygues, Deutsche Telekom, Telefonica, Vodafone or other networks actually reaches the protected prefix.
The third is careful handoff design. GRE, IPIP, VXLAN and cross-connects each have different operational and latency implications. A tunnel is fast to deploy but adds encapsulation and depends on both underlay paths. A cross-connect is cleaner but requires datacenter presence.
The fourth is BGP traffic engineering. Communities, local-pref, selective announcements and more-specifics can improve paths, but they must be tested. Random AS path prepending rarely solves latency by itself.
- Low-latency DDoS protection in Europe: why Marseille is strategic
Connect latency and PoP positioning in Europe.
Concrete use case
A game server hosted in southern France may have excellent latency to French users but weaker paths to Central Europe depending on the upstream mix. If DDoS protection forces all traffic through a northern PoP, some users may see additional delay even when the attack is filtered.
A better design keeps the ingress close to the natural route where possible and uses protected transit or tunnels that do not create unnecessary detours. For some customers, a cross-connect or nearby router VM is better than a long tunnel across Europe. For others, a tunnel is acceptable because deployment speed matters more.
The decision should be based on measurements: baseline latency by ASN, packet loss, jitter, ingress volume and behavior during mitigation. Without those measurements, “low latency” is just a slogan.
Frequent mistakes
- Judging latency only from one looking glass or one speed test.
- Ignoring the return path after clean traffic delivery.
- Assuming anycast automatically gives the lowest latency to every user.
- Choosing a remote scrubbing center only because it has more advertised capacity.
- Forgetting tunnel overhead and underlay path quality.
- Not separating normal latency from latency during mitigation.
FAQ
Does Anti-DDoS always add latency?
Not necessarily. A well-placed mitigation path can be close to the natural route. Poorly placed scrubbing can add noticeable delay.
Is physical distance the main factor?
It matters, but BGP policy, upstream quality and congestion can matter just as much.
Is GRE bad for latency?
GRE itself is not the problem. The underlay path, MTU, encapsulation handling and return routing are what matter.
