The bug id you provided describes exactly what happened for us.
I could assume that they are similar bugs (or have same root issue), but they
have different "fixed in" lists...
CSCta33973 is fixed in 12.0(33)S5
CSCsy27511 is not fixed there according to bug toolkit
But you refer to SA which also referenced from CSCta33973 :)
So are those the same or not ?
Now i'm confused
Shimol Shah wrote:
Rodney, Luc and myself had a detailed discussion internally on this.
Below is our summary of this issue. Sharing for everyone's benefit.
We think a large but valid AS PATH was originated by someone/somewhere,
which included at-least one 4 byte ASN. When this reached the border
router which was 4 byte ASN capable, it corrupted the update when
sending it to ASN2 only peer. So the ASN2 peer on receiving it reset the
peer-ship to ASN4 peer and logged the notification 3/4 message.
This is a bug on the border router. It is addressed via CSCsy27511.
The issue can be possibly worked around by configuring "bgp maxas-limit
#" knob on the ASN4 capable upstream(border, box corrupting the
packet), but issue with that is there is no right value to use for it.
We have been able to reproduce above with a AS path length as small as 35.
So recommendation is to upgrade past the above bug.
A more compelling reason to upgrade are the more serious issues of:
http://www.cisco.com/warp/public/707/cisco-sa-20090729-bgp.shtml
Shimol
On 6/18/10 9:59 AM, Rodney Dunn wrote:
That's not it. Shimol is formulating an update on the issue and correct
bug id. Stand by...
On 6/18/10 8:41 AM, Tima Maryin wrote:
I've been told by TAC that this problem caused by CSCta33973
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