Summary
- New backbone links connect Sofia directly with Frankfurt and Istanbul.
- The operator advertises three distinct westbound paths using Istanbul, Sofia and Athens.
- Effective resilience depends on physical route diversity, available capacity and the customer’s routing policies.
DE-CIX has activated additional backbone connections linking Sofia with Frankfurt and Istanbul, completing a set of three geographically diverse westbound routes intended to improve access to European cloud, content and interconnection infrastructure.
The new links connect the BIX.BG internet exchange in the Bulgarian capital directly with DE-CIX Frankfurt, and connect Sofia with DE-CIX Istanbul. Existing routes through Istanbul and Athens provide the other paths identified by the operator for networks seeking onward connectivity towards Germany.
DE-CIX says it has designed the paths to reduce overlapping physical dependencies, allowing traffic to use alternatives if an individual terrestrial or subsea route is disrupted or congested. The announcement concerns backbone connectivity; it does not mean every connected network automatically receives resilient services or guaranteed failover.
Frankfurt is a major European internet exchange and data centre hub. Networks operating in Southeast Europe, Türkiye and neighbouring markets depend on onward connectivity for services hosted in Frankfurt and other western European locations, including cloud platforms and large computing installations.
An internet exchange allows separately operated networks to establish traffic relationships, often reducing the need to route data through additional transit providers. The underlying service can involve physical cross-connections at exchange facilities, backbone carriage between cities and commercial agreements governing how traffic is exchanged.
Alternative connectivity can support replication, access to central services and distributed applications across an organisation operating several European facilities. It may also provide a route for restoring connectivity when a shared cable corridor experiences damage.
DE-CIX advertises connectivity to Frankfurt from Sofia with latency below 35 milliseconds, from Istanbul below 40 milliseconds and from Athens below 50 milliseconds. Those figures describe its stated network capabilities. They are not guaranteed end-to-end application latency for a customer whose own access network, routing and upstream providers may add delay.
The new Sofia–Istanbul connection is separately advertised with latency below 12 milliseconds between the cities. It is intended to improve access to content and services hosted in the Balkan market, as well as providing an alternative route to central Europe.
Physical route diversity matters because two nominally separate commercial connections can share the same underground duct, cable landing station or exchange building. A single accidental excavation, equipment failure or other local incident may then interrupt both connections. True diversity requires examining the infrastructure actually used, not simply buying circuits labelled as redundant.
DE-CIX describes the backbone as using geographically redundant, non-overlapping routes. Customers will still need to check the degree of independence provided by their particular service and where a connection passes through third-party networks or common facilities.
Routing control is a further requirement. Operators use policies and protocols to determine how traffic moves between networks and when it should move to another path. An alternate link may be physically available but unused if customer routing configurations or commercial arrangements do not allow traffic to move to it.
Capacity also affects the outcome of a failure. A backup path that carries only a fraction of a customer’s normal traffic may maintain essential connectivity but be unable to preserve usual performance. Networks with critical workloads need realistic failover tests, traffic prioritisation and visibility of congestion during an interruption.
According to the reported operating figures, DE-CIX Istanbul connects about 70 networks and has reached traffic peaks of 613Gbit/s. BIX.BG is reported to connect 136 networks, with peak exchange traffic above 1.3Tbit/s. Those figures describe the respective exchange environments and must not be taken as dedicated capacity reserved on the new backbone links.
The new connections can give network providers more choices when designing routes between regional markets and the European cloud infrastructure concentrated around Frankfurt. They may also help operators distribute traffic across terrestrial and submarine systems during periods of damage or maintenance.
The new backbone should also be distinguished from new data centre capacity. It carries traffic between existing exchange environments and cannot by itself increase the power or floor space available to cloud operators in Frankfurt. Its value is in the paths and interconnection options available to network customers, not in creating additional computing infrastructure.
What customers obtain in practice will depend on the service purchased, the topology of their last-mile access, the capacity they reserve and the rules governing failover. The additional routes expand the available engineering options; the resilience of each deployed connection has to be proved in operation.
