load+OH+Stuffing) 44,736,000 5,592,000.0 Bytes Packets IP Payload (4 x 188 Bytes) 6,016 752.0 IP Header UDP Header RTP Header Sub-Total - Overhead ("Packet Tax") Transmission Unit Payload 6,336 792.0 IP Packets On DS3 Payload 44,209,694 5,526,211.8 6,977.5 Next Lowest Octal Number Evently Divisible By 6336 44,206,272 5,525,784.0 Additional Stuffing Required 3,422 427.8 Overhead 529,728 66,216.0 Maximum Practical IP Payload in DS3 44,206,272 5,525,784.0 6,977.0 Total (Payload+OH+Stuffing) 44,736,000 5,592,000.0 Next, what's the maximum program content payload? Easy, just divide the bits into headers and content. Content in each frame APPENDIX TABLE 3 TDM ATM and IP Transport Comparison Channel Overhead Available 44,736,000 526,306 44,209,694 44,209,632 44,206,272 amounts to 6,016 bits. Multiply that by 6,977, and the resulting content payload is 41,973,632bps. Summarize the numbers from the three alternatives and this is the payload from a network perspective of the three alternatives-TDM, ATM, and IP transport techniques. Table 2 shows how the three techniques compare when given a fixed rate program content pay- load. In practice, more detailed design analysis on ATM and IP is likely to result in a set of trade-offs that can be used to structure proposal preparation and analysis with suppliers. From a content perspective, the payload is not a single entity. The numbers above are summarized from allocation of bits to audio, video, closed captioning, and other data that may be required such as vertical interval test signals. As a first order estimate, this process can be built from basics by assuming or taking rates for each, sum- marizing them, and adding markup percentages to account for MPEG transport stream overhead and forward error correction arrive at a program content payload estimate. The markups are summarized as follows: MPEG Transport Stream 3.125% (On top of MPEG Markup) GLOSSARY Analog Analog means "representative of." If something is analo- gous, then it is a copy or representative of the original. I