[j-nsp] BGP error messages

[Tay Chee Yong]

Hi Daniel,

Do you have any idea which relase of ERX code has the bug in the TCP stack
fixed?
Please advise.

Thanks.

Regards,
Cheeyong

On Mon, 14 Oct 2002, Daniel Roesen wrote:

> On Mon, Oct 14, 2002 at 09:55:10AM +0800, Tay Chee Yong wrote:
> > My juniper router is facing an ERX router via ATM using ip address 192.168.1.1
> > and .2, and we are running bgp between this link.
> >
> > However, our bgp is resetting pretty frequently. One of the recent cause of
> > resetting is due to a TCP error on both ends. In addition, what does the
> > statement "connection collision prefers 192.168.1.2+1926 (proto)" means?
> >
> > Error messages from Juniper (JUNOS 5.0R5.1):
> >
> > Oct 14 07:36:01 juniper2 rpd[15846]: bgp_traffic_timeout: NOTIFICATION sent to
> > 192.154.24.74 (External AS 9989): code 4 (Hold Timer Expired Error), Reason:
> > holdtime expired for 192.168.1.2 (External AS xxxx)
> > Oct 14 07:36:01 juniper2 rpd[15846]: bgp_event: peer 192.168.1.2 (External AS
> > xxxx) old state Established event HoldTime new state Idle
> > Oct 14 07:37:07 juniper2 rpd[15846]: bgp_pp_recv: NOTIFICATION sent to
> > 192.168.1.2 (External AS xxxx): code 6 (Cease), Reason: dropping 192.168.1.2
> > (External AS xxxx), connection collision prefers 192.168.1.2+1926 (proto)
> > Oct 14 07:37:07 juniper2 rpd[15846]: bgp_recv: peer 192.168.1.2 (External AS
> > xxxx): received unexpected EOF
> > Oct 14 07:37:17 juniper2 rpd[15846]: bgp_event: peer 192.168.1.2 (External AS
> > xxxx) old state OpenConfirm event RecvKeepAlive new state Established
>
> What happens is: BGP (TCP) session times out (holdtime expired), then
> the session is tried to bring up again, but one side didn't time out
> the session yet - so the TCP state of the original session was still
> there and it get's confused. The new attempt is let fallen on the floor
> ("connection collision"). The second re-establishment attempt then works.
> (sorry if that's wrong, I'm pre-caffeein).
>
> We had once the very same problem of Junipers running JunOS 5.x (not
> seen with 4.4!) dropping BGP sessions to ERXes frequently. We were
> after long weeks of examination able to prove that there was an
> implementation bug in the TCP stack used by ERX for BGP with handling
> retransmits. This bug was fixed with later ERX software releases.
>
> So try using newer ERX software, I know of no work-around. Drop me
> a mail if you need further info (bug ID etc.) if you need them and
> I try to find out.
>
>
> Best regards,
> Daniel
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