rame check sequence field, inclusive. The default maximum frame size is 1518 octets; the minimum size is 64 octets. The preamble field is 7 octets in length and is used SO that the receive PLS can synchronize to the transmitted symbol stream. The SFD is the binary sequence 10101011. It follows the preamble and delimits the start of frame. There are two address fields: the source address and the destination address. The address field length is an implementation decision. It may be 16 or 48 bits long. In either field length, the first bit specifies whether the address is an individual address (bit set to 0) or group address (bit set to 1). In the 48-bit address field, the second bit specifies whether the address is globally administered (bit set to 0) or locally administered (bit set to 1). For broadcast address, the bit is set to 1. The length field is 2 octets long and indicates the number of LLC data octets in the data field. If the value is less than the minimum required for proper operation of the protocol, a PAD field (sequence of octets) is appended at the end of the data field and prior to the FCS field. 3 The length field is transmitted and received with the high-order octet first. The data (LLC data) field contains a sequence of octets that is fully transparent in that any arbitrary sequence of octet values may appear in the data field up to the maximum number specified by the implementation of the standard that is used. The maximum size of the data field supplied by the LLC is determined by the maximum frame size and address size parameters of a particular implementation. The FCS field contains four octets (32 bits) CRC value. This value is computed as a function of the contents of the source address, destination address, length, LLC data, and pad-that is, all fields except the preamble, SFD, and FCS. The encoding is defined by the following generating polynomial: x23 + 22 An invalid MAC frame meets at least one of the following conditions: 1. The frame length is inconsistent with the length field. 2. It