MAC Address Table not updating

[salomidhogela]

I have an issue where by the mac address table is not refreshing on cisco 9300 switches. Cisco IOS XE Software, Version 17.03.05

Regards,

Salom

[balaji.bandi]

check this thread and bug :

https://community.cisco.com/t5/switching/cisco-9300mac-address-table-not-refreshing/m-p/4713240

[salomidhogela]

I just realized that I have experienced almost the similar issue. However with the current issue is that with no portsecurity configured, mac address table is not refreshing after 5 minutes. This usually happen on interfaces where an unamaged switch is connected. 

Regards,

Salom

[balaji.bandi]

Since unmanaged device not gone done, those ARP will not be flushed until it get automatic timeout, so decrease the ARP time out.

check output wherre the unmanaged device connected (what is the arp timeout)

show interface gigx/x

ARP type: ARPA, ARP Timeout 04:00:00

decrease the timers example :

interface gig0/0 (this where unmanged switch conencted)

arp timeout XX (what ever time you need in seconds)

[salomidhogela]

The timeout is current set to 4hrs, and from my observation this mac stays on the interface for even a month. Will adjusting the timer really resolve the issue. 

GigabitEthernet1/0/12 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is *************** (bia ************)
Description: *************
MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 100Mb/s, media type is 10/100/1000BaseTX
input flow-control is on, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:05:55, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:00:03
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 33000 bits/sec, 14 packets/sec
5 minute output rate 124000 bits/sec, 17 packets/sec
67 packets input, 18062 bytes, 0 no buffer
Received 0 broadcasts (0 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
55 packets output, 22489 bytes, 0 underruns
Output 0 broadcasts (0 multicasts)
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

Tx

Salom

[balaji.bandi]

Post the interface config both cisco side and 3com side, also show example that MAC staying for Long output for us to verify,

as mentioned try decreasing the timers.

show mac-address-table aging-time  (show you global timers) - if you like you can tweak this and observe

mac-address-table aging-time command.

Note : what you see on the 3COM, is the MAC table flush learning from cisco side  to 3com ?

[salomidhogela]

show mac address-table aging-time

Global Aging Time: 300
Vlan Aging Time
---- ----------

interface GigabitEthernet1/0/12
description *******
switchport access vlan X
switchport mode access

tx

Salom

[balaji.bandi]

post the example of MAC address table was in the database for ever ?

have you tried arp time out under interface as suggestged before ?

[MHM Cisco World]

can I know more detail 
what is the unmanaged SW you talk about ?
what is link between 9000 and unmanaged SW ?

[salomidhogela]

It's a 3Com Baseline switch, connect via a cat6 fly lead from the data port. 

[jox198501]

Hi.

Sry if i hop in with question about mac adress table :

i have a multilayerswitch in packet tracer, with 2 vlans 10 and 20, and 1 pc in each of the vlan, and SVI 10 and 20 for routing between them
i want to know how cef table work, so i got that part until adjacency table which shows:

sh adjacency detail

and it says for example:
protocol IP, interface VLAN20, address 10.1.20.100 (pc2 address), and L2 rewrite header with source and dest mac address.

Is the last step before forwarding paket to PC2, to check MAC ADRESS TABLE also ?
because there is no output port in show adjacency
and there is one in mac address table:

vlan 20
mac address mac_of_pc2
type dynamic
port f0/1

so,in cef routing decision, after fib and adjacency table, is it correct that in this case last step in order to send packet from pc1 to pc2, is to chek mac adress table for destination address of pc2, in order to know what is the egress port to pc2 ?

tnx

[balaji.bandi]

Google has many examples of how that works.

look below example :

https://networklessons.com/switching/cef-cisco-express-forwarding