In the trunk example, which statement is true?

In the trunk example, which statement is true?

• A. None of the hosts can ping each other
• B. Hosts on VLAN 11 can ping VLAN 111
• C. Hosts on VLAN 111 can ping VLAN 11
• D. Hosts on both VLANs can ping each other

Answer: (B)

Inter-VLAN routing on a trunked link is what makes this possible. A trunk carries multiple VLANs, but hosts in different VLANs live in separate L2 domains, so they can’t reach each other without a Layer 3 device to route between the VLANs. When routing is configured, a host in one VLAN can reach a host in another VLAN as long as the path back is allowed as well. In this scenario, the observed connectivity shows that a host in VLAN 11 can reach a host in VLAN 111. That means the inter-VLAN route from VLAN 11 toward VLAN 111 is functioning and the destination is reachable. The return path from VLAN 111 to VLAN 11 would require a corresponding route and an unblocked return path; if that return traffic is blocked (for example, by an ACL on the routing interface or by a misconfigured return route), the reverse ping would fail. So the statement that matches what’s working is that hosts on VLAN 11 can ping hosts on VLAN 111.

Inter-VLAN routing on a trunked link is what makes this possible. A trunk carries multiple VLANs, but hosts in different VLANs live in separate L2 domains, so they can’t reach each other without a Layer 3 device to route between the VLANs. When routing is configured, a host in one VLAN can reach a host in another VLAN as long as the path back is allowed as well.

In this scenario, the observed connectivity shows that a host in VLAN 11 can reach a host in VLAN 111. That means the inter-VLAN route from VLAN 11 toward VLAN 111 is functioning and the destination is reachable. The return path from VLAN 111 to VLAN 11 would require a corresponding route and an unblocked return path; if that return traffic is blocked (for example, by an ACL on the routing interface or by a misconfigured return route), the reverse ping would fail. So the statement that matches what’s working is that hosts on VLAN 11 can ping hosts on VLAN 111.