Re: [C-bgp-users] a problem about c-bgp in importing as-level topology from caida

[Bruno Q. <bru...@um...>]

Hello,

Looks like CAIDA has changed its file format since this parser was 
implemented in c-bgp (without notifying me ! ;-)). The version used in 
the regression tests dates back from 2007. Unfortunately, I don't have 
time to update c-bgp source code in the near future to provide 
out-of-the-box support for the new file format.


However, it might be possible to adapt your input file so that it will 
be accepted by the current version of c-bgp. There are 3 main issues 
with the file you sent (20160601.as-rel.txt).

1). Change in delimiter

In the former file format, every relationship was encoded as

     <ASx> <ASy> <type>

With the new format, relationships are encoded as

     <ASx> | <ASy> | <type>

You can change the delimiter using the following shell code :

     awk -F '|' '{print $1" "$2" "$3}' 20160601.as-rel.txt > 
20160601.as-rel.oldfmt.txt


2). Too long lines

With the new format, some lines have a potentially unbounded length. 
This is the case for the comment line that provides "# IXP ASes". That 
line will not be parsed correctly by the current c-bgp "caida parser". 
You need to remove it. Generally speaking, every line with more than 80 
characters will be considered multiple, separate lines and must be 
removed for the parser to succeed.

This can be solved by removing every comment line (i.e. lines starting 
with '#').

     grep -v '^#' 20160601.as-rel.oldfmt.txt > 
20160601.as-rel.oldfmt-no-comments.txt


3). 32-bits ASN

ASNs higher than 65535 will not be accepted. There is nothing that can 
be done with these ASNs right now. Relationships involving such ASN need 
to be removed.

It seems 41967 relationships among the 230216 in the file are concerned 
however...

     awk '{if ($1 <= 65535 && $2 <= 65535) print $1" "$2" "$3}' 
20160601.as-rel.oldfmt.txt > 20160601.as-rel.oldfmt-16asn.txt


Best regards,
Bruno





On 12/06/16 06:05, 贾溢豪 wrote:
> Hello, everyone:
>    I want to use c-bgp to analyze the AS-level topology. But the AS 
> relationship file-"20160601.as-rel.txt" from CAIDA can not be import 
> by command "bgp topology load --format=caida "20160601.as-rel.txt", 
> neither can other files from caida I have tried. Its error message is 
> "could not load topology "as-rel.2011.01.16.txt" (invalid number of 
> parameters, at line 130)".
>
>    please help me. Thank you.
>
>
>
> -- 
>
> Best Regards.
>
> *
> *
>
> *Yihao Jia*
>
> Ph.D. Candidate
> Institute for Network Sciences and Cyberspace
> Tsinghua University
>
>
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