Broadcastverkehr

Broadcastverkehr, or broadcast traffic, is network traffic that is delivered to all nodes within a broadcast domain. In Ethernet networks this typically involves frames addressed to the broadcast MAC address ff:ff:ff:ff:ff:ff and flooded to all ports in the same VLAN. Broadcast traffic serves essential functions, such as address resolution and dynamic addressing, and is used by protocols like ARP and DHCP to reach devices that have not yet learned specific address information.

In practice, switches usually confine broadcasts to the VLAN in which they originated. Routers or Layer 3 switches block broadcast traffic from crossing VLAN boundaries, so segmentation with VLANs is a primary method to limit broadcast domains. However, broadcast traffic can still become problematic if misconfigurations, faulty hardware, or certain protocols cause excessive broadcasting or broadcast storms. Sources include ARP requests, DHCP discovery messages, network discovery tools, and devices that improperly flood frames (for example, in hubs or bridged environments). Excessive broadcasts can consume bandwidth, increase CPU load on devices, and degrade overall network performance.

To manage broadcastverkehr, network designers use several strategies. Segmenting networks with VLANs to reduce broadcast domains is fundamental. Implementing storm control on switches helps cap the rate of broadcast frames and can prevent congestion during transient faults. Other measures include configuring DHCP snooping to prevent rogue DHCP traffic, enabling appropriate security features to isolate ports, and optimizing multicast with mechanisms like IGMP snooping where multicast traffic is preferred over broadcast. Regular monitoring of broadcast volume with network management tools aids in early detection of misconfigurations or faulty devices.

See also: broadcast domain, VLAN, ARP, DHCP, broadcast storm, multicast, switch, router.