Encountering a strange issue with a Cisco 3850 that is in use as a core switch. It is flooding all ports on the switch with traffic. After investigating more, it appears that the CAM table is not updating, and is empty aside from the built in addresses.
Using Cacti to monitor the interfaces, I can see a large amount of outbound traffic to each port, with no correlating incoming traffic on any of the other ports. I set up a monitor port and watched the traffic with wireshark, and I am seeing traffic that most certainly should not be on that port.
There dont appear to be any spanning tree issues that I can identify. I will be disabling uplinks one by one in a little bit to test.
I am still really confused why the switch is not populating the mac address-table, there is enough traffic that I would figure it would have updated by now.
Output of 'show mac address-table'
Vlan Mac Address Type Ports
---- ----------- -------- -----
All 0100.0ccc.cccc STATIC CPU
All 0100.0ccc.cccd STATIC CPU
All 0100.0ccc.ccce STATIC CPU
All 0180.c200.0000 STATIC CPU
All 0180.c200.0001 STATIC CPU
All 0180.c200.0002 STATIC CPU
All 0180.c200.0003 STATIC CPU
All 0180.c200.0004 STATIC CPU
All 0180.c200.0005 STATIC CPU
All 0180.c200.0006 STATIC CPU
All 0180.c200.0007 STATIC CPU
All 0180.c200.0008 STATIC CPU
All 0180.c200.0009 STATIC CPU
All 0180.c200.000a STATIC CPU
All 0180.c200.000b STATIC CPU
All 0180.c200.000c STATIC CPU
All 0180.c200.000d STATIC CPU
All 0180.c200.000e STATIC CPU
All 0180.c200.000f STATIC CPU
All 0180.c200.0010 STATIC CPU
All ffff.ffff.ffff STATIC CPU
1 dca5.f433.1bc7 STATIC Vl1
10 dca5.f433.1bc6 STATIC Vl10
30 dca5.f433.1be5 STATIC Vl30
40 dca5.f433.1be4 STATIC Vl40
50 dca5.f433.1be8 STATIC Vl50
20 dca5.f433.1bd6 STATIC Vl20
15 dca5.f433.1bd4 STATIC Vl15
Total Mac Addresses for this criterion: 28
Output of 'show mac address-table count'
Mac Entries for Vlan 1:
---------------------------
Dynamic Address Count : 0
Static Address Count : 1
Total Mac Addresses : 1
Mac Entries for Vlan 10:
---------------------------
Dynamic Address Count : 0
Static Address Count : 1
Total Mac Addresses : 1
Mac Entries for Vlan 30:
---------------------------
Dynamic Address Count : 0
Static Address Count : 1
Total Mac Addresses : 1
Mac Entries for Vlan 40:
---------------------------
Dynamic Address Count : 0
Static Address Count : 1
Total Mac Addresses : 1
Mac Entries for Vlan 50:
---------------------------
Dynamic Address Count : 0
Static Address Count : 1
Total Mac Addresses : 1
Mac Entries for Vlan 20:
---------------------------
Dynamic Address Count : 0
Static Address Count : 1
Total Mac Addresses : 1
Mac Entries for Vlan 99:
---------------------------
Dynamic Address Count : 0
Static Address Count : 0
Total Mac Addresses : 0
Mac Entries for Vlan 15:
---------------------------
Dynamic Address Count : 0
Static Address Count : 1
Total Mac Addresses : 1
Total Mac Address Space Available: 32752
Output of sh arp summary
Total number of entries in the ARP table: 424.
Total number of Dynamic ARP entries: 412.
Total number of Incomplete ARP entries: 3.
Total number of Interface ARP entries: 9.
Total number of Static ARP entries: 0.
Total number of Alias ARP entries: 0.
Total number of Simple Application ARP entries: 0.
Total number of Application Alias ARP entries: 0.
Total number of Application Timer ARP entries: 0.
Interface Entry Count
Vlan15 2
GigabitEthernet1/0/24 4
Vlan20 124
LIIN0 1
Vlan40 40
Vlan30 28
Vlan10 222
GigabitEthernet1/0/1 3
Super confused here! Any ideas?
