It may happen that when trying to reach the Exadata machine using the management network, the data center switch that connects to the Exadata Cisco switch get a 'connection rejected' error.
On X7-2 port 48 of the Cisco switch is setup by default as ‘spanning tree network’ that set the BPDU* filter to disable, and communications between customer switch and the Cisco are rejected.
To solve run this command on the Cisco:
Enabling BPDU filtering in the interface level stops sending or receiving BPDU on this interface; this is the same as disabling spanning tree on the interface.
See on My Oracle Support: Cisco 93108 switch is getting Error Disabled on the Uplink Switch (Doc ID 2360702.1)
* BPUD stands for: Bridge Protocol Data Unit. BPDUs are data messages that are exchanged across the switches within an extended LAN that uses a spanning tree protocol topology