Re: [LARTC] how to get the latency down on maxed out classes?
On Saturday 07 December 2002 17:49, Abraham van der Merwe wrote: Hi Stef! Does anybody have any idea how to get the latency down and still maintain the correct throughput? If you want low latency for some traffic (ping, telnet, ssh), then you can create a separate class for it. And if you have a 64kbit modem, you have to be sure you never send more data then the modem can handle. If you send more data, the hugh modem queue's will be filled so they create a lot of latency. So for a 64kbit link, try to limit ALL traffic to 60kbit so the queue's of the modem are never filled. I'm doing all my tests under ideal conditions (over 100mbit lan and shaping the traffic to something low such as 384kbit). The problem is that the latency becomes unnatural. If you have a normal line, e.g. 64kbit and you saturate the line, the latency still stays within limits, but with HTB, the latency can become very high if you have multiple concurrent tcp sessions going at full steam in a class. I can understand why it does this, but I need a way to get the latency down to acceptable limits. The only thing where I can think of, is adding a small fifo to each class. But you already tried and it created packets loss. So I can't help you. Stef -- [EMAIL PROTECTED] Using Linux as bandwidth manager http://www.docum.org/ #lartc @ irc.oftc.net ___ LARTC mailing list / [EMAIL PROTECTED] http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
Re: [LARTC] how to get the latency down on maxed out classes?
If you have a normal line, e.g. 64kbit and you saturate the line, the latency still stays within limits, but with HTB, the latency can become very high if you have multiple concurrent tcp sessions going at full steam in a class. I can understand why it does this, but I need a way to get the latency down to acceptable limits. Are you sure the latency and packet loss are not the same, when you have the same queue size as the router has ? Is the traffic locally generated (on the same machine as the HTB is running) ? If so then perhaps that's the difference. ___ LARTC mailing list / [EMAIL PROTECTED] http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
[LARTC] how to get the latency down on maxed out classes?
lets say I want to limit traffic to/from client to 64kbit. now, client opens a tcp connection blasting away at full speed. If client now pings isp, it gets on average around 7 seconds latency. I tried to improve this by using SFQ on the leaf nodes of my HTB hierarchy, but that does not really improve the situation, only makes it much worse. with SFQ I get anything between 250ms and 13 seconds latency. You understand what's going on here? As I recall, both pfifo and sfq default to queues of length 128 packets. If you fill that with 1500 byte packets you have ~200Kbytes which is about 1.6Mbits. At 64Kbit/sec that would take ~30 sec to send so your latency could be as high as 30 sec. You can limit this latency by reducing the queue size. On the other hand, the application that fills the queue evidently doesn't mind large latency. Otherwise it wouldn't fill the queue. I think I posted to this list once a description (maybe even the code?) of another way to limit latency - drop packets that have been in the queue for more than a timeout period (I tend to use 3 sec). SFQ should have the desirable result that one tcp connection won't slow down another one or a ping. I then tried fifos. With small packet fifos the packet loss is just to great to be of any use and even then the latency is quite high (~200ms). You consider 200ms high? One max size packet = 1500 bytes = 12Kbit which is about 200ms on a 64Kbit link. You can't expect to do better. I'm thinking of using RED, but the number of parameters is daunting and I have no idea how the HTB rate correlates to packet size and burst rates for red. RED should be independent of HTB. ___ LARTC mailing list / [EMAIL PROTECTED] http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
[LARTC] 100 Mbit/64 Kbit problem..
Hello.im pretty new in advanced routing and limiting issues. i have read a little and decided to ask you guys before anything else. this is a simple graph of my home network: cli1 cli2 cli3 | | | eth0 eth1 | | | BBone - [ME] (100Mbit Switch) cli5 256Kbit 100Mbit | \| |\ | cli4 (10Mbit Hub) | |eth1 [server] |eth0 | cli6---(10Mbit Hub)--cli7 As i originally limited the traffic with cbq.init,all the clients had 64 kbps outside the network,but inside too.So like,if i ping the eth1 interface of the [server] it was like 0.5 ms,but if i'd ping the eth0 there were like 3,4 seconds. Basically i want all the LAN clients to have 100 or 10 Mbits inside,in my [ME] eth1 interface,and limited at 64 Kbits only outside the network. I'd appreciate if you'll give me some hints in creating the correct cbq ierarchy to have at least full 10 Mbit inside and for all the clients the 64 Kbit limit outside of [ME]. Thanks in advance. ___ LARTC mailing list / [EMAIL PROTECTED] http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
[LARTC] neughbour table overflow
hi all, am getting neighbour table overflow messages very often... Dec 9 09:59:54 ICG kernel: NET: 13 messages suppressed. Dec 9 09:59:54 ICG kernel: Neighbour table overflow. Dec 9 09:59:59 ICG kernel: NET: 12 messages suppressed. Dec 9 09:59:59 ICG kernel: Neighbour table overflow. how can i stop/reduce it ?? what factors does it depends on ?? kernel configuration are... CONFIG_IP_ADVANCED_ROUTER=y CONFIG_IP_MULTIPLE_TABLES=y CONFIG_IP_ROUTE_FWMARK=y CONFIG_IP_ROUTE_NAT=y CONFIG_IP_ROUTE_MULTIPATH=y CONFIG_IP_ROUTE_TOS=y CONFIG_IP_ROUTE_VERBOSE=y CONFIG_IP_ROUTE_LARGE_TABLES=y CONFIG_IP_PNP=y CONFIG_IP_PNP_DHCP=y # CONFIG_IP_PNP_BOOTP is not set # CONFIG_IP_PNP_RARP is not set thanking you in advance.. A.H ___ LARTC mailing list / [EMAIL PROTECTED] http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
