[asterisk-users] Setting the TOS using IPtables screws up the DSCP field
Concise summary: When I set the TOS to Minimize-Delay the DSCP field in the packet changes from Expedited Forwarding to Unknown Here are the details: Scenario 1: IpTables is not used to set the TOS This is what the packet looks like using wireshark: Internet Protocol, Src: 59.93.192.xx (59.93.192.xx), Dst: 64.62.134.yyy (64.62.134.yyy) Version: 4 Header length: 20 bytes Differentiated Services Field: 0xb8 (DSCP 0x2e: Expedited Forwarding; ECN: 0x00) 1011 10.. = Differentiated Services Codepoint: Expedited Forwarding (0x2e) ..0. = ECN-Capable Transport (ECT): 0 ...0 = ECN-CE: 0 Scenario 2: IpTables is used to set the TOS Output of $/etc/rc.d/init.d/iptables status Table: mangle Chain PREROUTING (policy ACCEPT) num target prot opt source destination Chain INPUT (policy ACCEPT) num target prot opt source destination Chain FORWARD (policy ACCEPT) num target prot opt source destination 1TOSudp -- 0.0.0.0/00.0.0.0/0 udp dpts:5060:5069 TOS set 0x10 2TOStcp -- 0.0.0.0/00.0.0.0/0 tcp dpts:5060:5069 TOS set 0x10 3TOSudp -- 0.0.0.0/00.0.0.0/0 udp dpts:1:2 TOS set 0x10 This is what the packet looks like using wireshark: Internet Protocol, Src: 59.93.192.xx (59.93.192.xx), Dst: 64.62.134.xxx (64.62.134.xxx) Version: 4 Header length: 20 bytes Differentiated Services Field: 0xb0 (DSCP 0x2c: Unknown DSCP; ECN: 0x00) 1011 00.. = Differentiated Services Codepoint: Unknown (0x2c) ..0. = ECN-Capable Transport (ECT): 0 ...0 = ECN-CE: 0 I have no idea what am I doing wrong. Here is some reference reading I did: http://www.tucny.com/dscptos Any pointers in the right direction will be very much appreciated. Thanks for your time, Sysadmin http://www.debtconsolidationcare.com Internets First get out of debt community ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Setting the TOS using IPtables screws up the DSCP field
This happens because the TOS and DSCP are the same field. TOS is the first implementation of QoS on the IP header, DSCP is it's evolution and uses the same field on the IP header, you can use only one of the two at the same time. Best Regards, On Wed, May 7, 2008 at 8:59 AM, Vikas [EMAIL PROTECTED] wrote: Concise summary: When I set the TOS to Minimize-Delay the DSCP field in the packet changes from Expedited Forwarding to Unknown Here are the details: Scenario 1: IpTables is not used to set the TOS This is what the packet looks like using wireshark: Internet Protocol, Src: 59.93.192.xx (59.93.192.xx), Dst: 64.62.134.yyy (64.62.134.yyy) Version: 4 Header length: 20 bytes Differentiated Services Field: 0xb8 (DSCP 0x2e: Expedited Forwarding; ECN: 0x00) 1011 10.. = Differentiated Services Codepoint: Expedited Forwarding (0x2e) ..0. = ECN-Capable Transport (ECT): 0 ...0 = ECN-CE: 0 Scenario 2: IpTables is used to set the TOS Output of $/etc/rc.d/init.d/iptables status Table: mangle Chain PREROUTING (policy ACCEPT) num target prot opt source destination Chain INPUT (policy ACCEPT) num target prot opt source destination Chain FORWARD (policy ACCEPT) num target prot opt source destination 1TOSudp -- 0.0.0.0/00.0.0.0/0 udp dpts:5060:5069 TOS set 0x10 2TOStcp -- 0.0.0.0/00.0.0.0/0 tcp dpts:5060:5069 TOS set 0x10 3TOSudp -- 0.0.0.0/00.0.0.0/0 udp dpts:1:2 TOS set 0x10 This is what the packet looks like using wireshark: Internet Protocol, Src: 59.93.192.xx (59.93.192.xx), Dst: 64.62.134.xxx (64.62.134.xxx) Version: 4 Header length: 20 bytes Differentiated Services Field: 0xb0 (DSCP 0x2c: Unknown DSCP; ECN: 0x00) 1011 00.. = Differentiated Services Codepoint: Unknown (0x2c) ..0. = ECN-Capable Transport (ECT): 0 ...0 = ECN-CE: 0 I have no idea what am I doing wrong. Here is some reference reading I did: http://www.tucny.com/dscptos Any pointers in the right direction will be very much appreciated. Thanks for your time, Sysadmin http://www.debtconsolidationcare.com Internets First get out of debt community ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users -- Guilherme Loch Góes Visite nossa loja virtual: http://www.shopvoip.com.br Notícias e Fórum sobre VoIP com software livre: http://www.asteriskexperts.com.br ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Setting the TOS using IPtables screws up the DSCP field
Why are you trying to change the ToS from 46 (0x2e) Expedited for the RTP/RTCP packets to 16 (0x10)? I mean... these values really only need to be meaningful to yourself, your switches, your routers etc however ToS 46 (0x2e) is the standard value for RTP / RTCP as it is basically the highest priority value you can assign to something... ToS 46 is basically suppose to indicate that it trumps all other traffic and should be send before anything else (Which is a good thing for the RTP traffic) The SIP Signalling traffic is a little less important and its standard ToS value is 26 (0x1a). You also don;t need to use IPTables to set these values... Asterisk will do it for you as long as you have installed libcaps (I believe its required for it). And I don;t know what phones you are using... but your phones are probably also setting these values for you I know the Aastra phones have QoS/ToS settings under Options - Network - Type of Service -- Matt From: [EMAIL PROTECTED] [EMAIL PROTECTED] On Behalf Of Vikas [EMAIL PROTECTED] Sent: Wednesday, May 07, 2008 7:59 AM To: Asterisk Users Mailing List - Non-Commercial Discussion Subject: [asterisk-users] Setting the TOS using IPtables screws up the DSCP field Concise summary: When I set the TOS to Minimize-Delay the DSCP field in the packet changes from Expedited Forwarding to Unknown Here are the details: Scenario 1: IpTables is not used to set the TOS This is what the packet looks like using wireshark: Internet Protocol, Src: 59.93.192.xx (59.93.192.xx), Dst: 64.62.134.yyy (64.62.134.yyy) Version: 4 Header length: 20 bytes Differentiated Services Field: 0xb8 (DSCP 0x2e: Expedited Forwarding; ECN: 0x00) 1011 10.. = Differentiated Services Codepoint: Expedited Forwarding (0x2e) ..0. = ECN-Capable Transport (ECT): 0 ...0 = ECN-CE: 0 Scenario 2: IpTables is used to set the TOS Output of $/etc/rc.d/init.d/iptables status Table: mangle Chain PREROUTING (policy ACCEPT) num target prot opt source destination Chain INPUT (policy ACCEPT) num target prot opt source destination Chain FORWARD (policy ACCEPT) num target prot opt source destination 1TOSudp -- 0.0.0.0/00.0.0.0/0 udp dpts:5060:5069 TOS set 0x10 2TOStcp -- 0.0.0.0/00.0.0.0/0 tcp dpts:5060:5069 TOS set 0x10 3TOSudp -- 0.0.0.0/00.0.0.0/0 udp dpts:1:2 TOS set 0x10 This is what the packet looks like using wireshark: Internet Protocol, Src: 59.93.192.xx (59.93.192.xx), Dst: 64.62.134.xxx (64.62.134.xxx) Version: 4 Header length: 20 bytes Differentiated Services Field: 0xb0 (DSCP 0x2c: Unknown DSCP; ECN: 0x00) 1011 00.. = Differentiated Services Codepoint: Unknown (0x2c) ..0. = ECN-Capable Transport (ECT): 0 ...0 = ECN-CE: 0 I have no idea what am I doing wrong. Here is some reference reading I did: http://www.tucny.com/dscptos Any pointers in the right direction will be very much appreciated. Thanks for your time, Sysadmin http://www.debtconsolidationcare.com Internets First get out of debt community ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
