Core router capabilities Which of the following describe functions that routers commonly perform in an IP internetwork?

Introduction / Context:
Routers interconnect multiple IP networks and forward packets between them. Understanding their key functions clarifies how traffic is directed, controlled, and secured in enterprise and service-provider environments. While some tasks overlap with other devices, routers remain central to inter-network operations.

Given Data / Assumptions:

• The functions listed are packet switching, packet filtering, internetwork communication, and path selection.
• We consider typical router capabilities with modern IOS or equivalent software.

Concept / Approach:

Packet switching is the fundamental act of forwarding packets from an ingress interface to an egress interface based on a routing table (or FIB/CEF). Packet filtering is achieved through ACLs, firewall features, or zone-based policies that permit or deny traffic. Internetwork communication is the core purpose: connecting different IP networks and enabling hosts on separate subnets to exchange data. Path selection occurs via routing protocols and administrative policies that determine the best next hop to reach a destination network.

Step-by-Step Solution:

Verification / Alternative check:

Traceroute reveals path selection decisions; ACL logs or counters prove filtering; throughput tests confirm switching performance. Combined, these demonstrate all listed functions.

Why Other Options Are Wrong:

• Choosing any single subset ignores the breadth of router capabilities.
• Routers routinely perform all four listed functions in production networks.

Common Pitfalls:

• Confusing switching (Layer 2) with packet switching (Layer 3 forwarding); routers perform the latter.
• Assuming filtering is only a firewall task; routers implement ACL-based filtering extensively.

Final Answer:

All of the above