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How Can I Identify the Cause When an OSPF Neighbor Relationship Stays in Exstart/Exchange State for a Long Time?

Latest reply: Jul 11, 2018 02:09:38 740 1 0 0 0

The Exstart/Exchange state indicating that the local switch is exchanging Database Description (DD) packets with a neighbor. If the Exstart/Exchange state lasts for a long time, check the following items:

  • Whether the MTU values on the local interface and neighboring interface are the same.
  • Whether the router IDs on the two devices are the same. The two devices must have different router IDs.
  • Whether the size of received packets exceeds the MTU of the interface. When this occurs, packets sent from the neighbor are dropped.
  • x
  • convention:

Created Jul 11, 2018 02:09:38

here are a few possibilities may cause OSPF Neighbor Relationship Stays in Exstart/Exchange State for a Long Time
1.same router ID between two device
The unicast connection is broken for the following reasons
1.Error VC/DLCI mapping in frame relay/ATM switch.
2.Access lists prevent unicast
3.The unicast is NAT transformed.
4.The network type between the PRI and the BRI/dial interface is the point-to-point network type.
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  • x
  • convention:


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