Readme: correct receive buffer section

Readme.md

@@ -21,10 +21,36 @@ http://localhost:8080/
 
 ## Note
 
-`babeld` can spew out massive amounts of route changes that can fill the netlink socket. 
+`babeld` can spew out massive amounts of route changes that can fill the
+netlink socket. `rmon` tries to allocate a 16MB receive buffer, which seems to
+be enough for the moment. For this to work check `/proc/sys/net/core/rmem_max`
+to be more than 16MB (16777216).
+
+### Set receive buffer size temporarily
+
+Do one of the following:
+
+```shell
+# echo 16777216 > /proc/sys/net/core/rmem_max
+```
+
+```shell
+# sysctl -w net.core.rmem_max=16777216
+```
+
+### Set receive buffer pemanently
+
+Add the following line to `/etc/sysctl.conf`:
+
+```
+net.core.rmem_max = 16777216
+```
+
+and run
+
+```shell
+# sysctl -p
+```
 
-Check your values:
 
-1. `/proc/sys/net/core/rmem_default` >= 1048576 (1MB)
-2. `/proc/sys/net/core/rmem_max` higher than the value above