 last-mile, access networks have not dropped as much as on long-haul core routes, the costs and complexity to upgrade middle-mile and access infrastructure are higher than those on core networks. This is because additional equipment is required due to the greater number of con- nections and routes. For example, access networks connect to millions of homes and buildings with vast numbers of separate cable runs. By contrast, undersea cabling sys- tems are thousands of miles long, and intercity routes run hundreds of miles. Thus, they require fewer connections and less equipment. There are numerous challenges in managing and upgrading networks; they need to be secure from hackers, have adequate capacity, and be sustainable during emergen- cies. Providing capacity during peak traffic periods is particularly important during disasters caused by severe weather or terrorist attacks, when governments and popula- tions depend on networks to communicate with emergency personnel and families. Providing funding for these capabilities does not add revenue, but is critical to the security of nations, commerce, and the ability to communicate during emergencies. Appendix APPENDIX Table 4-1 SONET Worldwide Standards and SONET/SDH Capacity North American Synchronous Synchronous European Digital Transport Synchronous Hierarchy Signal (STS) SONET Transfer Mode (SDH) Speed Levels Channels (STM) Levels Channels 52Mbps 28 DS1s or STM-0 21 E1s 1 DS3 155Mbps 84 DS1s or STM-1 63 E1s or 1 E4 3 DS3s 622Mbps OC-12 336 DS1s STM-4 252 E1s or 4 E4s or 12 DS3s 2,488Mbps OC-48 1,344 DS1s STM-16 1,008 Els or 16 or 48 DS3s 9,953Mbps OC-192 5,376 DS1s STM-64 4,032 E1s or 64 or 192 39.812Gbps OC-768 21,504 STM-256 16,128 E1s or DS1s or 256 E4s 768 DS3s Table 4-2 PON Standards 10G-EPON Broadband Gigabit Gigabit ATM PON Ethernet PON Ethernet PON Speed 622Mbps* (OC 622Mbps* 2.5Gbps 10 Gbps 12) downstream upstream and downstream downstream downstream 155Mbps* (OC 1.25 Gbps 1Gbps upstream 3) upstream upstream Or symmetric 10Gbps upstream and downstream Co