[c-nsp] need an idea -- router's all TCP sessions STUCK

[Kinczli Zoltán]

Hello,
 
  i'd need an idea here...
 
A router (c72k w NPE-G1, 12.3(6a)) runs OSPF, and MP-BGP, it's an MPLS/VPN PE.
Roughly in each 2,5-3 hours all of its TCP sessions (LDP and BGP) get stucked: hold timer exp, nbr down.
 
Strange:
   all OSPF neighbors are up and happy
   router can only ping neighbors via serial interfaces
        there are ATM uplinks, and serial 'downlink' to other/further PEs and CEs
   router can not initiate TCP sessions via the 'pingable' serial I/Fs,  ... nor via the others
 
A clear ip route * solves the issue!
 
all of the following together won't solve the issue though:
- shut/no shut on I/Fs with routing sources behind them (ospf neighbors),
- clear ip ospf proc
- clear adj
- clear tcp tcb *
- clear ip bg ne *
 
what's the difference between the clear ip route * and them?
 
there is plenty of contniuous free mem available... just before all of you ask:
 
router#sh mem summ
                Head    Total(b)     Used(b)     Free(b)   Lowest(b)  Largest(b)
Processor   62C7A200   456678912    28742624   427936288   425854868   425109588
      I/O    E000000    33554432     9864712    23689720    22977192    23398272

 
other info:
 
in  deb ip tcp trans there are lots of:
>> Nov 27 22:19:18.587 CET: TCP: Alert! Received a broadcast packet from x.y.z.o
        from different sources, not our address space
 
 
thanks for any idea
  -zoltan

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