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

Created: Jul 6, 2018 07:54:00Latest reply: Jul 11, 2018 02:09:38 736 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：

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liwaye

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.

x
convention：

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

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