18. Possible Changes to the ECN Field in the Network

18. Possible Changes to the ECN Field in the Network

This section systematically examines the various ways in which the ECN field might be modified in the network. This section examines the consequences of these modifications, specifically whether they are likely to result in behavior that is worse in any dimension (throughput, delay, fairness, or functionality) than if a router simply dropped a packet.

As background information, in IPv4, the IP header is protected against bit errors by a header checksum; this is not the case in IPv6. For IPv6, the ECN field could be modified accidentally by bit errors in a link or router, without being detected by an IP header checksum.