> -----Original Message----- > From: linux-ppp-owner@xxxxxxxxxxxxxxx > [mailto:linux-ppp-owner@xxxxxxxxxxxxxxx] On Behalf Of Jar > Sent: 21. oktober 2008 20:44 > To: linux-ppp@xxxxxxxxxxxxxxx > Subject: ppp0 and it's txqueuelen with HSDPA gsm modems > > Hello > > What would be "optimal" value for ppp0 device's txqueuelen, > when it is used with HSDPA gsm modem for link which downlink > speed is 1Mbit/s and uplink speed is 384kbit/s and ping > ~80..100 ms? Is the default value 3 just OK? > > -- > Best Regards, Jar Jar, I would suggest using normal TCP calculation, i.e. that you dimension the txqueue size after the "BDP rule": bandwidth x delay product. Using your outbound numbers this is: 1,000,000 x 0.1 = 100,000 bits = 12,500 bytes. Assuming 1500 byte packets, this is txqueue = 12,500 / 1500 = 8.3 packets. So you could try txqueue size in the region 8-10, this should prevent queue starvation at packet drop events caused by traffic overload, even if you only have one single TCP flow. Best regards, Arne Lie SINTEF ICT, Dept. of Communication Systems e-mail: arne.lie@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-ppp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
