[atlas] Strange and undocumented (?) result in traceroute JSON output

On 7/17/13 9:17 AM, Stephane Bortzmeyer wrote:
> Measurement #1013405 contains:
>
>          "result": [
>            {
>              "x": "*"
>            },
>            {
>              "late": 20,
>              "ttl": 61,
>              "from": "88.79.15.141",
>              "size": 96
>            },
>            {
>              "x": "*"
>            },
>            {
>              "x": "*"
>            }
>
> While "late" is documented
> <https://atlas.ripe.net/doc/data_struct#v4400_traceroute>, the lack of
> "rtt" field is not and crashes tools like json2traceroute.py.
tools like json2traceroute.py which aim to reconstruct the routing 
vector should be aware of responses which arrive out of order; packets 
which are 'late' or show 'ittl' in the result require special attention 
because the 'from' address listed verly likely is from a router at a 
different hop.


json2traceroute.py could simply ignore the 'strange' results by changing 
the lines

    ...
    else:
             rtt.append(hr["rtt"])
             hopfrom = hr["from"]
             ...

to

    ...
    elif (not "late" in hr) and (not "ittl" in hr):
             rtt.append(hr["rtt"])
             hopfrom = hr["from"]
             ...



-- Rene