This counter reports the total number of outbound packets that were not sent on a specific network interface of a Xen domain, despite no errors being detected, since that domain was created. An admin monitors it to detect outbound packet loss unrelated to transmission errors, which could point to congestion, rate limiting, or queue overflow on that virtual interface. For example, a rising xenNetworkOutDiscards count on a VM under heavy load could indicate its outbound queue is being overwhelmed even though the underlying network hardware reports no errors.