When implementing OSPF (Open Shortest Path First) on a network with MikroTik devices, it is important to understand how OSPF handles the transmission of information and how this affects the network.

OSPF is a link state protocol that uses specific message types to establish and maintain adjacency relationships with other OSPF routers.

It does not use broadcast in the traditional sense, as, for example, the RIP (Routing Information Protocol) protocol would. Instead, OSPF uses several more controlled and efficient communication methods:

1. Types of OSPF Messages

OSPF uses several message types to manage its routing process:

• Hello Packets: These packets are sent periodically to a multicast address (not broadcast in the traditional sense). On Ethernet networks, this address is 224.0.0.5, which is a multicast address intended for all OSPF routers.
• LSAs (Link State Advertisements): Once the adjacency relationship is established, changes in the network topology are communicated through LSAs, which are sent to multicast addresses.

2. Use of Multicast

OSPF uses multicast, not broadcast, addresses for most of its communications. This reduces the range and impact of OSPF traffic because multicast packets are only processed by devices that are configured to listen for those specific multicast addresses. Devices that do not participate in OSPF do not process these packets, reducing the load on the network.

3. OSPF areas

OSPF implementation in large networks can be structured in different areas to optimize performance and minimize LSA traffic. This means that only routers within the same OSPF area exchange complete link state information, further reducing unnecessary traffic throughout the network.

4. DR (Designated Router) and BDR (Backup Designated Router)

In larger networks, especially segments with multiple routers, OSPF elects a DR and a BDR to reduce the number of OSPF adjacencies required. The DR and BDR are the only ones that receive and retransmit link state updates from all other routers on the same broadcast network, which minimizes the amount of OSPF traffic and reduces the processing load on each individual router.

Conclusion

By implementing OSPF on a network with MikroTik devices, you would not be generating network broadcasts in the traditional sense, but rather you would be using well-controlled multicast-based communication methods that are inherent to OSPF.

This is designed to be efficient and scalable, even on larger networks, ensuring that only the necessary devices handle OSPF traffic, minimizing the impact on overall network performance.