Cisco Certified Network Associate (CCNA) Practice Exam

Which routing protocol supports routing update authentication, IP address conservation, and works with multiple vendors?

1. RIPv2

2. EIGRP

3. OSPF

4. RIPv1

The correct answer is: OSPF

The correct answer is OSPF (Open Shortest Path First). OSPF is a widely used link-state routing protocol that supports several advanced features, making it suitable for modern networking environments. One of the key attributes of OSPF is its support for routing update authentication. This feature enhances security by ensuring that routing updates are exchanged only between authorized routers, reducing the risk of malicious routing information being injected into the network. Additionally, OSPF is designed for efficient IP address utilization, which is crucial in today’s networks where IP addresses may be limited. OSPF uses a hierarchical structure with areas to optimize routing and conserve address space, making it more scalable and suitable for larger networks. OSPF's interoperability is another significant advantage. Being an open standard, it can work seamlessly across devices from multiple vendors, allowing diverse networking environments to integrate without compatibility issues. In contrast, RIPv2 and RIPv1 have limitations regarding authentication methods and are older distance-vector protocols that do not support some advanced features found in OSPF. EIGRP, while it does support multiple vendor devices through its capability to use a routing information protocol like IP, is primarily a Cisco proprietary protocol, which may restrict its deployment in multi-vendor scenarios.