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
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 Destination P Prf Metric 1 Metric 2 Next hop AS path * 91.201.176.0/22 B 170 100 0 >195.69.144.110 3356 21219 196638 I B 170 100 10 >193.0.0.147 12859 21219 196638 I B 170 100 50 >195.69.144.200 12859 21219 196638 I B 170 100 100 >195.69.144.35 12859 21219 196638 I B 170 100 >195.69.144.178 6320 3327 21219 196638 I B 170 100 0 >195.69.145.47 8218 3257 3356 21219 196638 I B 170 100 >195.69.144.50 1103 3549 3327 21219 196638 I B 170 100 >195.69.144.34 1103 3257 3356 21219 196638 I B 170 100 0 >195.69.145.144 1273 3549 3327 21219 196638 I B 170 100 100 >195.69.144.89 286 3549 3549 3327 21219 196638 I * 91.207.218.0/23 B 170 100 0 >195.69.144.110 3356 13249 6886 196629 I B 170 100 0 >193.0.0.147 3356 13249 6886 196629 I B 170 100 50 >195.69.144.200 12859 35320 196629 AS_TRANS ? B 170 100 100 >195.69.144.35 12859 35320 196629 AS_TRANS ? B 170 100 >195.69.144.178 6320 2914 35320 196629 AS_TRANS ? B 170 100 0 >195.69.145.144 1273 2914 35320 196629 AS_TRANS ? B 170 100 100 >195.69.144.89 286 2914 35320 196629 AS_TRANS ? B 170 100 0 >195.69.145.47 8218 3257 3356 13249 6886 196629 I B 170 100 >195.69.144.50 1103 3549 3356 13249 6886 196629 I B 170 100 >195.69.144.34 1103 3257 3356 13249 6886 196629 I * 195.88.52.0/23 B 170 100 0 >195.69.144.110 3356 13249 28761 196665 I B 170 100 0 >193.0.0.147 3356 13249 28761 196665 I B 170 100 50 >195.69.144.200 12859 13249 28761 196665 I B 170 100 100 >195.69.144.35 12859 13249 28761 196665 I B 170 100 0 >195.69.145.144 1273 3356 13249 28761 196665 I B 170 100 100 >195.69.144.89 286 3356 13249 28761 196665 I B 170 100 0 >195.69.145.47 8218 3257 3356 13249 28761 196665 I B 170 100 >195.69.144.50 1103 3549 3356 13249 28761 196665 I B 170 100 >195.69.144.34 1103 3257 3356 13249 28761 196665 I * 195.128.231.0/24 B 170 100 0 >195.69.144.110 3356 13249 6886 196629 35748 I B 170 100 10 >193.0.0.147 12859 35320 196629 AS_TRANS 35748 I B 170 100 50 >195.69.144.200 12859 35320 196629 AS_TRANS 35748 I B 170 100 100 >195.69.144.35 12859 35320 196629 AS_TRANS 35748 I B 170 100 >195.69.144.178 6320 2914 35320 196629 AS_TRANS 35748 I B 170 100 0 >195.69.145.144 1273 2914 35320 196629 AS_TRANS 35748 I B 170 100 100 >195.69.144.89 286 2914 35320 196629 AS_TRANS 35748 I B 170 100 0 >195.69.145.47 8218 3257 2914 35320 196629 AS_TRANS 35748 I B 170 100 >195.69.144.50 1103 3257 2914 35320 196629 AS_TRANS 35748 I B 170 100 >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
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.
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 <jlewis@packetnexus.com> 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.
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
participants (4)
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Andy Davidson -
Christian Koch -
James Aldridge -
Jason Lewis