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Annotation of embedaddon/mtr/FORMATS, revision 1.1.1.1

1.1       misho       1: 
                      2: The "split" format is for a separating the gui from the main program.
                      3: The main program can be installed setuid, and you don't want to link a
                      4: gui-library with a setuid program.
                      5: 
                      6: 
                      7: The split format is:
                      8: 
                      9: <pos> <host> <loss%> <rcvd pckts> <sent pckts> <best> <avg> <worst> 
                     10: 
                     11: 
                     12: The "raw" format is:
                     13: 
                     14: hostline|pingline|dnsline|timestampline
                     15: 
                     16: hostline:
                     17: h <pos> <host IP>
                     18: 
                     19: pingline:
                     20: p <pos> <pingtime (ms)>
                     21: 
                     22: dnsline: 
                     23: d <pos> <hostname>
                     24: 
                     25: timestampline:
                     26: t <pos> <pingtime> <timestamp>
                     27: 
                     28: 
                     29: Timestampline is not  yet implemented. Need to find out how to do
                     30: ICMP timestamping first. :-)
                     31: 
                     32: 
                     33: Someone suggested to put the following text here. As to context: Some
                     34: people are wondering why mtr sometimes reports hosts beyond the
                     35: destination host. 
                     36: 
                     37: 
                     38: The FINAL host will occasionally be mentioned at position n, n+1, n+2
                     39: etc.
                     40: 
                     41: You know traceroute, right? It sends a packet, waits for the reply to
                     42: come back and when it comes back, it sends the next packet.
                     43: 
                     44: If say hosts 5-8 do not send "time exceeded" packets, you'll wait a
                     45: 4*3 = twelve seconds extra before you get any results on hosts 9 and
                     46: further. MTR doesn't work like that.
                     47: 
                     48: In theory we could send out a probe for host 1-40 all at once. But
                     49: this would pose an unnecessary burden on the network. So what we do,
                     50: is we send out probes for a max of 5 hosts beyond where we've seen a
                     51: reply. So in the example above, we'd see a reply from router at
                     52: position 4, then we'd send out 5-9 (and because the max-host is now at
                     53: 9, we'll send them out at 1s/9 = 111ms intervals). When the reply from
                     54: host 9 comes back, we'll start probing for host 10-15 (at about 60ms
                     55: intervals). But suppose the network delay upto host 9 is already 200ms
                     56: and suppose our destination host is at position 11. Then by the time
                     57: the packet from host 11 comes back, we'll already have sent probe
                     58: packets for position 12, 13, and 14! Those will come back as
                     59: "destination reached" and be reported by the "raw" mode.
                     60: 
                     61: Curses mode will stop showing hosts with position numbers beyond the
                     62: first reply of the destination host. It could gather the information
                     63: about replies to packets sent as probes FURTHER than it actually is
                     64: into the line displayed at its true position, but it doesn't (yet).
                     65: 
                     66: In fact the above example is almost completely true:
                     67: 
                     68: % mtr -r -n -c 2 152.179.99.218 | tail -5
                     69:  13.|-- 144.232.18.238 0.0% 2 94.8 95.4 94.8 96.0 0.8
                     70:  14.|-- 152.63.16.182 0.0% 2 95.1 95.5 95.1 95.8 0.5
                     71:  15.|-- 152.63.64.106 0.0% 2 163.9 163.9 163.9 164.0 0.1
                     72:  16.|-- 152.63.50.89 50.0% 2 163.7 163.7 163.7 163.7 0.0
                     73:  17.|-- 152.179.99.218 50.0% 2 168.2 168.2 168.2 168.2 0.0
                     74: % mtr -l -c 2 152.179.99.218 | grep -v "^[dp]" |tail -7
                     75: h 10 144.232.1.41
                     76: h 11 144.232.4.96
                     77: h 16 152.179.99.218
                     78: h 17 152.179.99.218
                     79: h 18 152.179.99.218
                     80: h 12 144.232.18.238
                     81: h 13 152.63.16.182
                     82: 
                     83: As you can see we get the reply from the destination host at position
                     84: 16 AFTER we've sent probes for position 17 and 18. When those come
                     85: back, they are reported. That's what raw mode does. It reports the raw
                     86: information.
                     87: 
                     88: If you write a backend for the raw mode, it's up to you to
                     89: filter/display the results.
                     90: 
                     91: h 10 144.232.1.41
                     92: h 11 144.232.4.96
                     93: h 12 144.232.18.238
                     94: h 13 152.63.16.182
                     95: h 14 152.63.64.106
                     96: h 15 152.63.50.89
                     97: h 16 152.179.99.218
                     98: h 17 152.179.99.218
                     99: h 18 152.179.99.218
                    100: