What you have said makes absolute sense to me. However, I only "reserved" 136Kbit for the VoIP traffic, there are 44Kbit available even we assume the 180Kbit is the maximum. Why doesn't HTB allocate the 44Kbit to the class for ping traffic, which only require rate 4Kbit and 0.5 Kbit?
Some of this could be do to the fact that an ICMP echo request packet is extremely small. It is quite likely that your ADSL connection has a raw throughput of 256 kbps. On top of the ADSL signal is a signaling protocol, be it Frame Relay (older DSL circuits in my town are this) or ATM (newer DSL circuits), each have their own protocol overhead as well as minimum packet size. So if you are sending ICMP echo request packets that are very small, they will have to be wrapped in the network layer (OSI layer 2) packets and transmitted on the ADSL line (OSI layer 1) thus growing in size. It is quite likely that the size of the packets on physical layer are approaching 256 kbps and thus heating the physical maximum of your circuit. There is always the fact that ADSL is half duplex where as SDSL is full duplex. You would see this as a problem if you were trying to download something and upload something at the same time. Your circuit can only do one thing at a time thus somethi ng will have to wait. You will see this if you are able to FTP a large file out to a system on the net fast, close to your maximum, yet your VoIP (SIP?) traffic will start having problems at less than the maximum rate that the physical link can handle.
Any one care to support or refute this? I'm mainly going off of what I have read and discussed with others. I'm presently going after CCNA and this is the answer that I would give to a client, but if there is something better or there is a discussion that is to be had I'm game for it. Someone please correct me as I want to learn more. ;)
Grant. . . . _______________________________________________ LARTC mailing list LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
