How can I emulate DSL & Cable Modem connections?
DSL is typically an asymetric offering, with higher download speeds than upload speeds. Typical download speeds are 512kbps – 1.54Mbps and typical upload speeds are 128kbps – 512kbps. Cable modems are also asymetric, with similar upload speeds to that of DSL. The download speeds are often higher, ranging up to 3Mbps in many cases. It really depends on what the local DSL & Cable providers are selling, however. A good estimate for latency would be 35ms in both directions for a round-trip-time of 70ms. Packet loss should be rare providing you are not overloading the network under test (and overloading the network will drop packets independently of the packet-loss settings in LANforge anyway). Packet duplication and reordering should be extremely rare events. Cable & DSL emulations should have a backlog buffer of 16-32 in most cases. Larger buffers can seriously increase latency and/or make TCP/IP run sub-optimally. ISPs almost always oversell their bandwidth and assume that not everyone w
