[Kamailio-Users] 487

Hi, This question may belong in a general SIP forum - but I'll drop it here anyway, - hope I stir no big anger ;-) I'm running Kamailio 1.5, - use it for wholesale, and my customers typically send me calls from their Asterisk platform. I'm experiencing a very share of calls ending up in 487. This should be the client terminating the call - but is it my client (the provider with the Asterisk platform) or is it the final client - my client's client? Could Asterisk send a 487 for some reason? I've researched this (maybe not good enough!), but cannot find the answer: Does a 487 always mean that the client gave up and hung up? If this is the case, could high PDD be my problem - it's taking too long and the client gives up? Thanks!