Interswitchlinks

Interswitchlinks are network connections that join two or more switches to form a single switching fabric. They carry traffic between switches and can carry multiple VLANs when configured as trunk links, enabling communication across different parts of a network without requiring routing at every boundary. In many enterprise and data center environments, interswitchlinks form the backbone that ties together access, distribution, and core layers.

Typically, interswitchlinks are Ethernet-based and can use copper or fiber. They are often implemented as high-speed links such as 10, 40, or 100 gigabits per second to meet bandwidth demands. To increase aggregate capacity and provide redundancy, multiple physical interswitch links are commonly grouped into a single logical link using link aggregation (LACP). In larger or modern networks, interswitchlinks may be part of a spine-leaf topology or other scalable fabrics, where deterministic paths reduce congestion and improve performance.

Management of interswitchlinks involves ensuring consistent VLAN tagging, MTU settings, and quality of service policies across connected switches. Network administrators monitor link utilization, error rates, and latency, and implement redundancy to avoid single points of failure. Security considerations include restricting access to interswitchports, configuring appropriate VLAN segmentation, and applying port security measures to protect the switching fabric.

Related concepts include VLAN tagging and trunking, link aggregation, spanning tree protocols or alternative loop-free designs, and overlay technologies such as VXLAN in modern data centers. Interswitchlinks remain a fundamental element of network design, enabling scalable, efficient, and resilient switch-to-switch communication.