[OT] Request for help in figuring out passage of DSCPs

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1

Dear all,

I want to ask for volunteers that are willing and able to run a bsd/macos command and share the output with me (on- or off-list). Please note this requires a BSD/macos traceroute as only that offers the desired diagnostics:

traceroute -aID -t 180 nacktmulle.duckdns.org

This command will try to traceroute a host in AS 6805 with setting TOS 180 which corresponds to DSCP 45. The question I want to get a handle on is, how will the DSCP value be changed along the path and are these changes aligned with specific AS boundaries. Or put differently, how many ISPs modify DSCP 45 if sent from an end-user and what exact modification is performed.

Running this in a VM is fine, this is not performance critical it is just currently only BSD traceroute offers this diagnostic mode...

2

FreeBSD ok?

$ uname -a
FreeBSD rtropn.brain.lan 14.1-RELEASE-p5 FreeBSD 14.1-RELEASE-p5 stable/24.7-n267840-e62d514886a SMP amd64

$  traceroute -aID -t 180 nacktmulle.duckdns.org
traceroute to nacktmulle.duckdns.org (77.8.245.42), 64 hops max, 48 byte packets
 1  [AS0] rtr00 (10.1.1.1)  0.989 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf00000010100000a0101154d08f52a0800fb0efcef00010000000000000000000000000000000000000000
____________________6ee0________________________________________________________________________

 2  [AS0] 10.72.48.1 (10.72.48.1)  8.822 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf10000020100000a0101154d08f52a0800fb0dfcef00020000000000000000000000000000000000000000
________________01__6edf________________________________

 3  [AS0] 100.120.104.120 (100.120.104.120)  7.360 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf20000030100000a0101154d08f52a0800fb0cfcef00030000000000000000000000000000000000000000
__00____________01__6f92________________________________________________________________________0000000000000000000000000000000000000000

 4  [AS0] 100.120.104.16 (100.120.104.16)  4.454 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf30000040100000a0101154d08f52a0800fb0bfcef00040000000000000000000000000000000000000000
__00____________01__6f91________________________________

 5  *
 6  [AS1299] lax-b23-link.ip.twelve99.net (62.115.13.102)  7.836 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf50000060100000a0101154d08f52a0800fb09fcef00060000000000000000000000000000000000000000
__00____________01__6f8f________________________________________________________________________0000000000000000000000000000000000000000

 7  [AS1299] dls-bb2-link.ip.twelve99.net (62.115.123.136)  43.526 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf60000070100000a0101154d08f52a0800fb08fcef00070000000000000000000000000000000000000000
__00____________01__6f8e________________________________________________________________________0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200078740008010165810101

 8  [AS1299] dls-b23-link.ip.twelve99.net (62.115.138.65)  41.371 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf70000080100000a0101154d08f52a0800fb07fcef00080000000000000000000000000000000000000000
__00____________01__6f8d________________________________________________________________________0000000000000000000000000000000000000000

 9  [AS12956] 94.142.107.190 (94.142.107.190)  40.333 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf80000090100000a0101154d08f52a0800fb06fcef00090000000000000000000000000000000000000000
__00____________01__6f8c________________________________

10  [AS12956] 213.140.35.43 (213.140.35.43)  171.426 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcf900000a0100000a0101154d08f52a0800fb05fcef000a0000000000000000000000000000000000000000
__20____________01__6f6b________________________________________________________________________0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200085d30008010106225301

11  *
12  [AS12956] 176.52.248.88 (176.52.248.88)  166.215 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcfb00000c0100000a0101154d08f52a0800fb03fcef000c0000000000000000000000000000000000000000
__20____________01__6f69________________________________

13  [AS12956] o2-ae7-0-grtdusix1.net.telefonicaglobalsolutions.com (81.173.106.17)  169.528 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcfc00000d0100000a0101154d08f52a0800fb02fcef000d0000000000000000000000000000000000000000
__20____________01__6f68________________________________________________________________________0000000000000000000000000000000000000000

14  [AS6805] ae5-0.0002.cord.01.dus.de.net.telefonica.de (62.53.8.220)  181.705 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcfd00000e0100000a0101154d08f52a0800fb01fcef000e0000000000000000000000000000000000000000
__00____________01__6f87________________________________________________________________________00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002000f9e500080101040fe101

15  [AS6805] gigabitethernet100-0-0-4.0002.dbrx.02.fra.de.net.telefonica.de (62.53.11.242)  173.831 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcfe00000f0100000a0101154d08f52a0800fb00fcef000f0000000000000000000000000000000000000000
__00____________01__6f86________________________________________________________________________00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002000f9e500080101040fe101

16  [AS6805] ge-1-0-0-0.0002.dcre.03.haj.de.net.telefonica.de (62.53.1.149)  176.843 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fcff0000100100000a0101154d08f52a0800fafffcef00100000000000000000000000000000000000000000
__00____________01__6f85________________________________________________________________________00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002000f9e500080101040fe101

17  [AS6805] bundle-ether2.0001.cord.01.ham.de.net.telefonica.de (62.53.14.231)  178.599 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fd000000110100000a0101154d08f52a0800fafefcef00110000000000000000000000000000000000000000
__00____________04__6c84________________________________________________________________________00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002000f9e500080101040fe101

18  [AS6805] 62.53.11.181 (62.53.11.181)  173.327 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fd010000120100000a0101154d08f52a0800fafdfcef00120000000000000000000000000000000000000000
__00____________05__6b83________________________________

19  [AS6805] dynamic-077-008-245-042.77.8.pool.telefonica.de (77.8.245.42)  181.165 ms
vhtslen id  off tlprsum srcip   dstip   typ cod sum
45b40030fd020000130100000a0101154d08f52a0800fafcfcef00130000000000000000000000000000000000000000
0000__000000____0000____0000000000000000______fd______12
1 Like
3

Thanks! It looks like your ISP already re-marks to all zero, while AS12956 (Telxius) internally uses 0x20 (CS1) for some part of its internal network.

4

I should have added my ISP is Cox on DOCSIS in southern California, if that adds any useful data.

1 Like
5

Thanks, the southern california location was likely from the AS1299 node in L.A., but Cox is useful information as is docsis/cable, thanks!