Cisco SG300 unable to learn mac addresses

[Kahlilevelyn]

Good Day,

Currently my SG300 switch cannot learn mac addresses. A show CDP neighbour only shows 1 device (a 2960 switch) my 2851 router and AP cannot be seen via CDP.

Heres a spanning tree output:

SW1#show spanning-tree

Spanning tree enabled mode RSTP
Default port cost method: long
Loopback guard: Disabled

Root ID Priority 32768
Address 00:af:1f:7e:e9:b9
This switch is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Number of topology changes 0 last change occurred 00:43:39 ago
Times: hold 1, topology change 35, notification 2
hello 2, max age 20, forward delay 15

Interfaces
Name State Prio.Nbr Cost Sts Role PortFast Type
--------- -------- --------- -------- ------ ---- -------- -----------------
gi1 enabled 128.49 20000 Frw Desg Yes P2P (RSTP)
gi2 enabled 128.50 2000000 Dsbl Dsbl No -
gi3 enabled 128.51 2000000 Dsbl Dsbl No -
gi4 enabled 128.52 2000000 Dsbl Dsbl No -
gi5 enabled 128.53 2000000 Dsbl Dsbl No -
gi6 enabled 128.54 2000000 Dsbl Dsbl No -
gi7 enabled 128.55 200000 Frw Desg Yes P2P (RSTP)
gi8 enabled 128.56 2000000 Dsbl Dsbl No -
gi9 enabled 128.57 2000000 Dsbl Dsbl No -
gi10 enabled 128.58 2000000 Dsbl Dsbl No -
gi11 enabled 128.59 2000000 Dsbl Dsbl No -
gi12 enabled 128.60 2000000 Dsbl Dsbl No -
gi13 enabled 128.61 2000000 Dsbl Dsbl No -
gi14 enabled 128.62 2000000 Dsbl Dsbl No -
gi15 enabled 128.63 2000000 Dsbl Dsbl No -
gi16 enabled 128.64 2000000 Dsbl Dsbl No -
gi17 enabled 128.65 2000000 Dsbl Dsbl No -
gi18 enabled 128.66 2000000 Dsbl Dsbl No -
gi19 enabled 128.67 2000000 Dsbl Dsbl No -
gi20 enabled 128.68 2000000 Dsbl Dsbl No -
gi21 enabled 128.69 2000000 Dsbl Dsbl No -
gi22 enabled 128.70 2000000 Dsbl Dsbl No -
gi23 enabled 128.71 2000000 Dsbl Dsbl No -
gi24 enabled 128.72 2000000 Dsbl Dsbl No -
gi25 enabled 128.73 2000000 Dsbl Dsbl No -
gi26 enabled 128.74 2000000 Dsbl Dsbl No -
gi27 enabled 128.75 2000000 Dsbl Dsbl No -
gi28 enabled 128.76 2000000 Dsbl Dsbl No -
Po1 enabled 128.1000 20000 Dsbl Dsbl No -
Po2 enabled 128.1001 20000 Dsbl Dsbl No -
Po3 enabled 128.1002 20000 Dsbl Dsbl No -
Po4 enabled 128.1003 20000 Dsbl Dsbl No -
Po5 enabled 128.1004 20000 Dsbl Dsbl No -
Po6 enabled 128.1005 20000 Dsbl Dsbl No -
Po7 enabled 128.1006 20000 Dsbl Dsbl No -
Po8 enabled 128.1007 20000 Dsbl Dsbl No -

SW1#

I think the issue is with Green energy, i tried to disable it however the issue still persists, this is causing the switch to not be able to forward traffic.

Also note all the ports towards my 2851 and my 1702i AP are UP and were working fine, suddenly  the switch stopped being able to learn any mac address other than that 1 switch.

[Michal Bruncko]

• your STP output shows only two ports in UP state
• better would be to provide "show interface status" output as well and provide port numbers where your two additional devices are connected
• also port configuration (to each device) or whole switch config could help
• I would also say: check if 2851 and 1702i AP are both UP (powered), if so, then check cabling.
• That Aironet AP is powered through switch? is your switch with PoE capability? Is PoE enabled globally and/or per port basis?