IP

IP multicast is used for group communication in IoT protocols but has no standard encryption mechanism (DTLS/encryption for IP multicast still unspecified), forcing insecure broadcast or host-based communication only.

Per-packet load distribution forwarding schemes cause packets to arrive out of order, triggering TCP's fast retransmit algorithm and causing the sender to reduce window size, dramatically reducing throughput.

IoT mesh networks create multi-link subnet topologies that violate IP's 1:1 mapping between Layer-2 links and IP subnets. This architectural mismatch complicates routing and addressing.

When two devices are assigned the same IP address on the same network, communication fails. Diagnosing which device caused the conflict requires network inspection.

TCP/IP architecture doesn't allow embedding application semantics into network packets, preventing application-level control over data transmission. This forces applications to build custom framing on top of TCP.

Multi-layer protocol stack organization (Sockets → TCP → IP → driver) requires costly layer transitions and data transformations at each boundary. Nearly one-quarter of small-packet processing time is spent on memory management (mbuf overhead and copying), and layer transitions consume significant processing overhead.

Diagnosing TCP/IP performance issues requires checking multiple system layers (host memory/CPU, link errors, IP fragmentation, TCP retransmission, buffer sizes, MTU settings), with many interdependent configuration parameters and no straightforward diagnosis methodology, making performance troubleshooting tedious and time-consuming.