 is not an integral number of octets in length. 3. The bits of the received frame (exclusive of the FCS itself) do not generate a CRC value identical to the one received. An invalid MAC frame is not passed to the LLC. The minimum frame size is 512 bits for the 10-Mbps data rate (Ref. 3). This requires a data field of either 46 or 54 octets, depending on the size of the address field used. The minimum frame size is based on the slot time, which for the 10-Mbps data rate is 512 bit times. Slot time is the major parameter controlling the dynamics of collision handling and it is: An upper bound on the acquisition time of the medium An upper bound on the length of a frame fragment generated by a collision The scheduling quantum for retransmission To fulfill all three functions, the slot time must be larger than the sum of the physical round-trip propagation time and the MAC sublayer jam time. The propagation time for 3 Minimum frame length is 64 octets. 11.6 LAN ACCESS PROTOCOLS a 500-m segment of 50-S2 coaxial cable is 2165 nsec, assuming that the velocity of propagation of this medium is 0.77 X 300 X 106 m/sec (Ref. 3). 11.6.2.1.1 Transmission Requirements. System model. Propagation time is critical for the CSMA/CD access method. The major contributor to propagation time is the coaxial cable and its length. The characteristic impedance of the coaxial cable is 50 So + 2 S. The attenuation of a 500-m (1640-ft) segment of the cable should not exceed 8.5 dB (17 db/km) measured with a 10-MHz sine wave. The velocity of propagation is 0.77c.4 4 The referenced maximum propagation times were derived from the physical configuration model described here. The maximum configuration is as follows: A trunk coaxial cable, terminated in its characteristic impedance at each end, consti- tutes a coax segment. A coax segment may contain a maximum of 500 m of coaxial cable and a maximum of 100 MAUs. The propagation velocity of the coaxial cable is assumed to be 0.77c minimum (c = 300,000 km/sec). The maximum end-to-end propagation delay