Re: AS path weirdness

2009-03-23 Thread Andy Davidson 


On 21 Mar 2009, at 02:48, Jason Lewis wrote:

I'm not entirely sure what I'm looking at. The reserved AS, 65490  
appears in parentheses and I've never seen that in MRT formatted  
data and not sure why it's happening.


This has been observed when a vendor runs 32-bit AS aware code on part  
of their edge, and non-32-bit AS aware code on a different part of  
their edge.


I'm also not clear on why I see 23456 *and* a 32 bit AS in the  
path.  Is anyone else seeing this or is it something wacky at RRC04?

91.207.218.0/23|29222 6830 (65490) 3356 35320 3.21 23456


There's some history with this prefix.

http://www.andyd.net/media/talks/asn4_breaks_network.pdf [from nanog45]

Andy

Re: AS path weirdness

2009-03-22 Thread Christian Koch 
a private asn in (parentheses) indicates a bgp confederation, i would
tend to think that there is some sort of mis-config or software bug in
one of the routers in that path thats leaking it

On Sun, Mar 22, 2009 at 7:51 AM, Jason Lewis  wrote:
> I was under the impression that MRT only used brackets for sets.  eg.
> [ASNUM]
>
> Thanks for taking a look.
>
> jas
>
> James Aldridge wrote:
>> Jason Lewis wrote:
>>> I'm not entirely sure what I'm looking at. The reserved AS, 65490
>>> appears in parentheses and I've never seen that in MRT formatted data
>>> and not sure why it's happening.
>>
>> That would be a single-element AS_SET, I guess.
>>
>
>

Re: AS path weirdness

2009-03-22 Thread Jason Lewis 
I was under the impression that MRT only used brackets for sets.  eg.
[ASNUM]

Thanks for taking a look.

jas

James Aldridge wrote:
> Jason Lewis wrote:
>> I'm not entirely sure what I'm looking at. The reserved AS, 65490
>> appears in parentheses and I've never seen that in MRT formatted data
>> and not sure why it's happening.
> 
> That would be a single-element AS_SET, I guess.
>

Re: AS path weirdness

2009-03-22 Thread James Aldridge 
Jason Lewis wrote:
> I'm not entirely sure what I'm looking at. The reserved AS, 65490
> appears in parentheses and I've never seen that in MRT formatted data
> and not sure why it's happening.

That would be a single-element AS_SET, I guess.

> I'm also not clear on why I see 23456 *and* a 32 bit AS in the path.  Is
>  anyone else seeing this or is it something wacky at RRC04?

That's certainly not limited to rrc04.  From one of our routers at the AMS-IX
I see the following (JunOS 9.2, so 32-bit AS numbers are in "ASPLAIN" format
and AS_TRANS is spelt out):

A DestinationP Prf   Metric 1   Metric 2  Next hopAS path
* 91.201.176.0/22B 170100  0 >195.69.144.110  3356 21219 
196638 I
 B 170100 10 >193.0.0.147 12859 21219 
196638 I
 B 170100 50 >195.69.144.200  12859 21219 
196638 I
 B 170100100 >195.69.144.35   12859 21219 
196638 I
 B 170100>195.69.144.178  6320 3327 
21219 196638 I
 B 170100  0 >195.69.145.47   8218 3257 
3356 21219 196638 I
 B 170100>195.69.144.50   1103 3549 
3327 21219 196638 I
 B 170100>195.69.144.34   1103 3257 
3356 21219 196638 I
 B 170100  0 >195.69.145.144  1273 3549 
3327 21219 196638 I
 B 170100100 >195.69.144.89   286 3549 3549 
3327 21219 196638 I

* 91.207.218.0/23B 170100  0 >195.69.144.110  3356 13249 
6886 196629 I
 B 170100  0 >193.0.0.147 3356 13249 
6886 196629 I
 B 170100 50 >195.69.144.200  12859 35320 
196629 AS_TRANS ?
 B 170100100 >195.69.144.35   12859 35320 
196629 AS_TRANS ?
 B 170100>195.69.144.178  6320 2914 
35320 196629 AS_TRANS ?
 B 170100  0 >195.69.145.144  1273 2914 
35320 196629 AS_TRANS ?
 B 170100100 >195.69.144.89   286 2914 
35320 196629 AS_TRANS ?
 B 170100  0 >195.69.145.47   8218 3257 
3356 13249 6886 196629 I
 B 170100>195.69.144.50   1103 3549 
3356 13249 6886 196629 I
 B 170100>195.69.144.34   1103 3257 
3356 13249 6886 196629 I

* 195.88.52.0/23 B 170100  0 >195.69.144.110  3356 13249 
28761 196665 I
 B 170100  0 >193.0.0.147 3356 13249 
28761 196665 I
 B 170100 50 >195.69.144.200  12859 13249 
28761 196665 I
 B 170100100 >195.69.144.35   12859 13249 
28761 196665 I
 B 170100  0 >195.69.145.144  1273 3356 
13249 28761 196665 I
 B 170100100 >195.69.144.89   286 3356 
13249 28761 196665 I
 B 170100  0 >195.69.145.47   8218 3257 
3356 13249 28761 196665 I
 B 170100>195.69.144.50   1103 3549 
3356 13249 28761 196665 I
 B 170100>195.69.144.34   1103 3257 
3356 13249 28761 196665 I

* 195.128.231.0/24   B 170100  0 >195.69.144.110  3356 13249 
6886 196629 35748 I
 B 170100 10 >193.0.0.147 12859 35320 
196629 AS_TRANS 35748 I
 B 170100 50 >195.69.144.200  12859 35320 
196629 AS_TRANS 35748 I
 B 170100100 >195.69.144.35   12859 35320 
196629 AS_TRANS 35748 I
 B 170100>195.69.144.178  6320 2914 
35320 196629 AS_TRANS 35748 I
 B 170100  0 >195.69.145.144  1273 2914 
35320 196629 AS_TRANS 35748 I
 B 170100100 >195.69.144.89   286 2914 
35320 196629 AS_TRANS 35748 I
 B 170100  0 >195.69.145.47   8218 3257 
2914 35320 196629 AS_TRANS 35748 I
 B 170100>195.69.144.50   1103 3257 
2914 35320 196629 AS_TRANS 35748 I
 B 170100>195.69.144.34   1103 3257 
2914 35320 196629 AS_TRANS 35748 I

AS_TRANS and a 32-bit ASN only seem to appear together in the paths through
35320 so it looks as though something odd is going on there.

James

AS path weirdness

2009-03-20 Thread Jason Lewis 
I'm seeing the following in the MRT data from RRC04 at ripe.
http://www.ripe.net/projects/ris/rawdata.html

http://data.ris.ripe.net/rrc04/2009.03/bview.20090320.2359.gz for reference.

I'm not entirely sure what I'm looking at. The reserved AS, 65490
appears in parentheses and I've never seen that in MRT formatted data
and not sure why it's happening.

I'm also not clear on why I see 23456 *and* a 32 bit AS in the path.  Is
 anyone else seeing this or is it something wacky at RRC04?

91.201.176.0/22|29222 6830 (65490) 3356 21219 3.30
91.207.218.0/23|29222 6830 (65490) 3356 35320 3.21 23456
195.88.52.0/23|29222 6830 (65490) 3356 13249 28761 3.57
95.128.230.0/24|29222 6830 (65490) 2914 35320 3.21 23456 35748
195.128.231.0/24|29222 6830 (65490) 2914 35320 3.21 23456 35748


jas