--- Ed Wildgoose <lists@xxxxxxxxxxxxxx> wrote: > > >http://www.lammertbies.nl/comm/info/RS-232_flow_control.html > >ECN is software flow control. There is also icmp for software FC? The > >idea is too prevent 'buffer underruns' in the modem, any SNMP or other > >stats on this buffer would also provide SWFC. > > > > > > I don't consider this to be "flow-control" in the sense of throttling > sending. This is really a syncronisation protocol. > Yes, SwFC is lame. Howerver it would be a good band-aid, to have router and modem syncronisation take place. > >http://www.nwfusion.com/netresources/0913flow.html > >This is ethernets HWFC, that any directly connected modem could use. > The > >idea then is for the directly connected computer to use SwFC(ECN or > >?icmp?) to pass this FC onto other hosts using the modem. > > > > > > Hmm, I wasn't aware of a "pause" ability for ethernet. But still this > is a very low level layer 1 protocol. In other words this will calm > your 100mb net card talking to your 10mbit port on your cable modem. > But it has no idea that the cable modem only has a 256kb link > The router(PC) has no idea of the buffer fullness, this is the underlying problem! The cable modem needs to triger a "pause" when it's buffer reaches %80 full, regardless of any other rate limiting. Linux kernel can do this with some cards, under heavy CPU strain(htb). CONFIG_NET_HW_FLOWCONTROL: net/Kconfig > You need something which works at IP level or above. TCP (level higher) > No, the DEVICE is not > layer 3. It's simply a bridge, with a stoplight on one end. The idea is to not make any cars crash, that has nothing todo with the ball game a car might want to get too. > has some stuff, but (I repeat) it basically involves dropping traffic > until the sender slows down. There are protocols like ECN, but they are > Yes, ECN will/should be used for routers attached to bridges. > broadly unsupported. ICMP stuff is frequently dropped by > routers/firewalls making it problematic (look at how difficult it is > just to do MTU discovery!) > ECN makes this a non-issue. > What's your question though? Read the LARTC howto and the ADSL QOS > howto. They are both excellent docs. Also read up on some basic TCP > notes. There is nothing really clever that you can do - it's all in the > > docs you just have to work around the limitations of the protocols > I would like to know is maby a ?$6000.00? Cisco cable mobem will not only use HwFC but ECN as well? Thought i'd like to find a $150.00 modem that will just do HwFC, maby an internal one? > Ed W > __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - Send 10MB messages! http://promotions.yahoo.com/new_mail _______________________________________________ LARTC mailing list / LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
