URBANIAK@G.BBN.COM (09/21/88)
broadcast ICMP echo request is certainly guaranteed to provoke a massive collision (if many IP implementations respond), but this is not synonymous with being obnoxious or being a VERY BAD idea. I think I would call it an unusual, potentially dangerous action. If viewed as another LAN management tool, it can be useful, as mentioned, to locate quickly all active IP stations on a broadcast LAN. I see this as a useful, off-hours verification against address assignment databases. Certainly I would wish to request users not to issue such broadcasts, but I'm not sure that users stations should be mandated not to respond to a broadcast request. (Being one of many tools, you might conclude that the safest network behaviour is to constrain the IP behaviour. But maybe this is just a user behaviour prophylactic, not a protocol design goal. don't you really want an implementation switch: do/don't respond to IP broadcast ICMP Echo, for individual sites to set?) Also, massive LAN collisions are not necessarily to be avoided, they are to be managed, which might mean avoidance during prime time to some sites. Generating a test massive collision with IP broadcast might tell you how different implementations behave, which are more/less robust, what the settling time for this incident is for a given LAN, how your network components are responding. My view is that many production LANs permit some wee hour testing or preventive maintenance and learning on the real live network. I'm not sure how much of real LAN management might not be considered to be "unusual" and "potentially dangerous" from the perspective of a user who was yet to benefit immediately and directly. Walter doc Urbaniak. Urbaniak@BBN.COM (800 station Ethernet)