What is the most effective way to address the issue of limited ports on a Junos switch connected to a router with multiple VLANs?

Configuring a single trunk interface to carry traffic for all VLANs is the most effective approach when dealing with limited ports on a Junos switch connected to a router with multiple VLANs. A trunk interface allows multiple VLANs to share a single physical link, which optimizes the use of existing switch ports. This is achieved by encapsulating each VLAN's traffic using tagging protocols such as IEEE 802.1Q.

Utilizing a trunk interface streamlines network resources by reducing the need for additional physical connections. It provides a means for multiple VLANs to communicate over one interface, maintaining separation of traffic through tagging. This configuration is especially beneficial in scenarios where port availability is a concern, allowing for efficient bandwidth usage without compromising the integrity of each VLAN's data.

Other strategies, such as installing additional switches or using switch management software, could potentially alleviate port limitations but don't directly address the fundamental issue of port scarcity. Assigning each VLAN to a different subnet is also not a solution that directly resolves port limitations; it is more of an IP design consideration rather than a physical port issue. Therefore, the trunk configuration stands out as the most efficient and effective solution in this context.