/// The speed, in OCTETS per second, of the link over which the Outbound/Return Packet will be sent.
/// Since it will not be long before network speeds exceed 4.3Gb/s, and since some machines deal poorly with fields longer than 32 bits, octets per second was chosen over bits per second.
/// If this value cannot be determined, the field should be set to zero.
/// A gateway receiving an address mask request should return it with the address mask field set to the 32-bit mask of the bits identifying the subnet and network,
/// for the subnet on which the request was received.
/// </para>
///
/// <para>
/// If the requesting host does not know its own IP address, it may leave the source field zero; the reply should then be broadcast.
/// However, this approach should be avoided if at all possible, since it increases the superfluous broadcast load on the network.
/// Even when the replies are broadcast, since there is only one possible address mask for a subnet, there is no need to match requests with replies.
/// The "Identifier" and "Sequence Number" fields can be ignored.
/// </para>
/// </summary>
AddressMaskRequest=0xA1,
/// <summary>
/// RFC 950.
///
/// <para>
/// A gateway receiving an address mask request should return it with the address mask field set to the 32-bit mask of the bits identifying the subnet and network,
/// for the subnet on which the request was received.
/// </para>
///
/// <para>
/// If the requesting host does not know its own IP address, it may leave the source field zero; the reply should then be broadcast.
/// However, this approach should be avoided if at all possible, since it increases the superfluous broadcast load on the network.
/// Even when the replies are broadcast, since there is only one possible address mask for a subnet, there is no need to match requests with replies.
/// The "Identifier" and "Sequence Number" fields can be ignored.
/// </para>
/// </summary>
AddressMaskReply=0xA2,
/// <summary>
/// RFC 1393.
/// </summary>
Traceroute=0x1E,
/// <summary>
/// RFC 1475.
/// The introduction of network layer conversion requires a new message type, to report conversion errors.
/// Note that an invalid datagram should result in the sending of some other ICMP message (e.g., parameter problem) or the silent discarding of the datagram.
/// This message is only sent when a valid datagram cannot be converted.
/// </summary>
ConversionFailed=0x1F,
/// <summary>
/// RFC 1788.
/// </summary>
DomainNameRequest=0x25,
/// <summary>
/// RFC 1788.
/// Parsing of this datagram isn't supported because its parsing is not clear from the RFC.