BGP and Peering: How Routing Works for ISPs and Hosting Providers

In the world of telecommunications and professional hosting, connectivity quality is not measured solely in megabits per second, but above all in the intelligence with which traffic is routed. For Internet Service Providers (ISPs), structured web agencies, and hosting companies, a deep understanding of BGP (Border Gateway Protocol) and peering dynamics is fundamental to guaranteeing stable, fast, and resilient services.

In this technical article, we will explore how routing works on a global scale, the crucial difference between peering and IP Transit, and how the advanced use of tools such as BGP Communities and BGP FlowSpec can radically transform network performance. At Servereasy, operating directly from the main datacenters in Milan, we offer carrier-class solutions specifically designed for those who need large capacity and total control over their traffic.

What is BGP (Border Gateway Protocol) and Why is it Vital for ISPs?

The Border Gateway Protocol (BGP) is, without mincing words, the protocol that makes the Internet work. While internal routing protocols (such as OSPF) manage traffic within a single corporate network, BGP is the “global postman” that decides how data packets should travel between different and independent networks on a worldwide scale.

For an ISP or hosting provider, BGP is not an option, but an absolute necessity. Without BGP, a network would be isolated, unable to communicate to the rest of the world which IP addresses it manages and how to reach them. The protocol constantly analyzes global “routing tables,” evaluating multiple possible paths to reach a destination and choosing the optimal one based on predefined policies, path length (AS Path), and commercial agreements.

Autonomous Systems (AS) and the Map of the Internet

To actively participate in global BGP routing, an organization must possess an Autonomous System Number (ASN). An Autonomous System (AS) is a network, or group of networks, under the control of a single administrative entity (such as an ISP, a large university, or a technology company like Servereasy) that presents a clear and defined routing policy toward the Internet.

When BGP routers communicate with each other, they exchange information about the blocks of IP addresses (prefixes) that each AS can reach. This immense web of interconnected ASes forms the backbone of the Internet. Having your own ASN and directly managing BGP sessions means having total control over your network destiny, without blindly depending on the routing decisions of a single upstream provider.

Peering vs IP Transit: What is the Difference?

In the vocabulary of network operators, the terms “peering” and “IP Transit” are often used, but they represent two profoundly different commercial and technical concepts.

IP Transit is a commercial service in which an operator (the customer) pays another operator (the transit provider, usually a Tier 1 or Tier 2) to have access to the entire global Internet. The transit provider commits to routing the customer’s traffic to any worldwide destination and, conversely, to announcing the customer’s routes to the rest of the world. It is an asymmetric relationship: the customer pays for a complete service.

Peering, on the other hand, is an agreement (often free, known as “settlement-free peering”) between two networks to mutually exchange traffic destined exclusively for their respective customers. In peering, there is no provider and customer; there are two partners (peers) who find mutual benefit in exchanging traffic directly, bypassing costly transit providers.

The Advantages of Direct Peering (MIX and MINAP)

For a local ISP or hosting company located in Milan, establishing direct peering sessions at the main Italian Internet Exchange Points (IXPs), such as the MIX (Milan Internet eXchange) or MINAP, offers incalculable advantages. Latency is dramatically reduced because traffic between two peering networks travels directly through the IXP switch, without having to traverse intermediate nodes or leave national borders — a critical factor for real-time applications like VoIP, online gaming, or live streaming. Furthermore, every gigabit of traffic exchanged via peering is a gigabit that does not need to be paid to the IP Transit provider, generating massive cost savings for high-volume networks. Finally, having multiple paths (transit plus multiple peerings) means that if one link fails, traffic can be instantly re-routed over another path, guaranteeing superior uptime.

We at Servereasy maintain extensive direct connectivity relationships with major global operators, ensuring that traffic reaches its destination in the fastest and most efficient way possible.

Routing Optimization: BGP Communities and Traffic Engineering

Having multiple connections is only the first step; the real added value for an ISP lies in the ability to actively manipulate traffic. This is where BGP Communities come into play.

BGP Communities are essentially numerical “labels” (tags) that can be applied to routing announcements. These labels communicate to the routers of peering partners or transit providers how they should treat specific routes. For example, an ISP can use a specific BGP Community to tell its transit provider: “Do not announce this route of mine to operator X,” or “Lower the priority of this route in Europe.”

This process, known as Traffic Engineering, allows operators to balance the load on their links, avoid congested paths, and optimize costs. Our carrier-class infrastructure fully supports these advanced logics: we can implement custom BGP Communities tailored to your specific traffic engineering requirements, offering you a flexibility that standard providers simply cannot provide.

Advanced Security: The Role of BGP FlowSpec

In today’s landscape, network security is as critical as performance. Volumetric DDoS (Distributed Denial of Service) attacks can quickly saturate an ISP’s links, causing cascading service disruptions for all customers. Traditionally, DDoS mitigation required routing anomalous traffic to costly “scrubbing” appliances.

Today, the BGP FlowSpec (Flow Specification) standard represents the cutting edge of network defense. FlowSpec extends BGP’s capabilities by allowing routers to exchange not only information on “how to reach a destination,” but also extremely granular traffic filtering rules. An operator can use FlowSpec to tell all routers on their network (and those of compatible partners): “Immediately discard all UDP packets from port 53 directed to IP 192.0.2.1.”

This ability to distribute mitigation rules in fractions of a second across the entire routing infrastructure allows DDoS attacks to be blocked directly at the network “edge,” before they can saturate internal links. All of our core routers natively support the BGP FlowSpec standard, guaranteeing immediate responsiveness against volumetric threats.

Servereasy’s Carrier-Class Infrastructure in Milan

To provide the highest level of connectivity to companies like Netsons, Aruba, or local ISPs, the physical infrastructure must be impeccable. Our IP Transit service is currently active at the most strategic datacenters in Italy: Settimo Milanese, Caldera 21 in Milan, and DATA4.

Our global network is based on a carrier-class routing infrastructure with a dual IPv4 and IPv6 protocol stack implemented on carrier-class optical fiber. This allows us to offer all our Points of Presence an IPv6 speed equivalent to the line’s transmission capacity, providing IPv6 service transparently and at no additional cost alongside existing IPv4 services.

We offer ports from 10 Gigabit Ethernet (10 GigE), 40 Gigabit Ethernet (40 GigE), and 100 Gigabit Ethernet (100 GigE), with guaranteed speeds and link aggregation capabilities for multi-node configurations. Billing is extremely flexible: it is possible to purchase the entire port (flat) or a fraction of it, with bandwidth calculated using the 95th percentile method (burstable), ensuring you pay only for what you actually use.

Dedicated Control Panel for Network Operators

We know that ISPs and network operators need real-time visibility and control. For this reason, we have developed a dedicated operational interface for the direct management of DDoS protection on IP addresses and subnets. Our control panel enables autonomous management of IPs and subnets, application of protocol and service filters, real-time traffic monitoring, consultation of attack and mitigation history, centralized firewall control, and sub-user management for technical teams. This tool is designed for use in production environments, with particular attention to stability and the speed of execution of critical operations during attacks.

Conclusion: The Importance of a Reliable Infrastructure Partner

Managing BGP routing, optimizing peering, and defending against DDoS attacks requires specialized expertise and a solid infrastructure. For ISPs, web agencies, and hosting companies located in Milan and throughout Italy, relying on a local partner with carrier-class capabilities means making a decisive quality leap.

We at Servereasy do not simply sell bandwidth; we provide advanced, secure, and scalable connectivity solutions, designed for those who make the Internet their core business. If your company needs large transit capacity, minimal latency, and integrated DDoS protection, we are ready to support your growth.

Are you an ISP or network operator? Contact us today to discuss your IP Transit needs and discover how our Milan infrastructure can optimize your BGP routing.

Servereasy Answers:

Staff Servereasy