We have been seeing many issues with Netgear routers (not only iRacing specific).
One member was able to resolve this by enabling Traffic Meter and set it to unlimited in the Netgear settings (see attached for assistance.
Others fixed this issue by adding in our port range and also changed to UDP only (instead of the default UDP and TCP) on their router settings .
Here is our FAQ on Port Ranges:
Other members have changed the QoS settings. Delete all those already on the list and put iRacing as highest priority with ports 15000-52500. Log onto your Router and go to QoS settings. Delete all those already on the list and put iRacing as highest priority with ports 15000-52500 and UDP only
You can also try replacing your router and see if that resolves this issue.
You may also find helpful information in these forum posts: http://members.iracing.com/jforum/posts/list/3486016.page#11154489 and http://members.iracing.com/jforum/posts/list/3614804.page#11174518