client.send(message, 0, message.length, 41234, "localhost");
client.close();
+**A Note about UDP datagram size**
+
+The maximum size of an `IPv4/v6` datagram depends on the `MTU` (_Maximum Transmission Unit_)
+and on the `Payload Length` field size.
+
+- The `Payload Length` field is `16 bits` wide, which means that a normal payload
+ cannot be larger than 64K octets including internet header and data
+ (65,507 bytes = 65,535 − 8 bytes UDP header − 20 bytes IP header);
+ this is generally true for loopback interfaces, but such long datagrams
+ are impractical for most hosts and networks.
+
+- The `MTU` is the largest size a given link layer technology can support for datagrams.
+ For any link, `IPv4` mandates a minimum `MTU` of `68` octets, while the recommended `MTU`
+ for IPv4 is `576` (typically recommended as the `MTU` for dial-up type applications),
+ whether they arrive whole or in fragments.
+
+ For `IPv6`, the minimum `MTU` is `1280` octets, however, the mandatory minimum
+ fragment reassembly buffer size is `1500` octets.
+ The value of `68` octets is very small, since most current link layer technologies have
+ a minimum `MTU` of `1500` (like Ethernet).
+
+Note that it's impossible to know in advance the MTU of each link through which
+a packet might travel, and that generally sending a datagram greater than
+the (receiver) `MTU` won't work (the packet gets silently dropped, without
+informing the source that the data did not reach its intended recipient).
### dgram.bind(port, [address])
-For UDP sockets, listen for datagrams on a named `port` and optional `address`. If
+For UDP sockets, listen for datagrams on a named `port` and optional `address`. If
`address` is not specified, the OS will try to listen on all addresses.
Example of a UDP server listening on port 41234: