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Is my L2 switch not recognizing our VLAN?


I think I'm having an issue with a L2 switch seeing a VLAN. I'm trying to add a printer to our network and add it to our printer VLAN. We did this without a hitch a couple of days at another site, but this new site has a couple of hops back to the mdf. I've exhausted pretty much all other ideas when I noticed the VLAN brief on the switch with the working printer looking like I would expect: 

31   Printer-Network                  active    Gi1/0/3

But, the VLAN brief showing the same VLAN on the switch with the non-working printer, not looking like it should: 

31   VLAN0031                         active    Gi0/7

This makes me wonder if it's even recognizing the VLAN. 

Addt'l info: 

So, the path goes like this:

Loc1-3560cg port Gi0/9 >> Loc2-3560cg port Gi0/10 >> Loc3-3850 port Gi2/0/22

We added a printer on port 7 for Loc1-3560cg. I changed the VLAN to include the printer VLAN (31)

interface GigabitEthernet0/7

 switchport access vlan 31

 switchport mode access

 switchport voice vlan 239

 spanning-tree portfast


I noticed on the trunk ports, they were not configured to include VLAN 31 so I added it to the outgoing port on our Loc 1 switch

interface GigabitEthernet0/9

 description Uplink Loc2

 switchport trunk encapsulation dot1q

 switchport trunk native vlan 1001

 switchport trunk allowed vlan 4,31,200,239,254

 switchport mode trunk

 media-type sfp


and the trunk port on Loc 2 switch


interface GigabitEthernet0/10

 description Downlink Loc1

 switchport trunk encapsulation dot1q

 switchport trunk native vlan 1001

 switchport trunk allowed vlan 4,31,200,239,254

 switchport mode trunk


Loc 3 already had it in range

interface TenGigabitEthernet2/0/22

 description Loc2

 switchport trunk native vlan 1001

 switchport trunk allowed vlan 1-100,102-252,254-4094

 switchport mode trunk


(I also added VLAN 31 to the outgoing port on Loc 2 to Loc 3)

interface GigabitEthernet0/9

 description Uplink Loc 3

 switchport trunk encapsulation dot1q

 switchport trunk native vlan 1001

 switchport trunk allowed vlan 4,5,31,34,134,200,239,254

 switchport mode trunk


Loc1-3560cg#sh vlan

VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Gi0/10
4 Loc1 active Gi0/1, Gi0/2, Gi0/3, Gi0/5
31 VLAN0031 active Gi0/6, Gi0/7
200 wireless-mgmt active Gi0/4, Gi0/8
239 Parks-VOIP active Gi0/1, Gi0/2, Gi0/3, Gi0/4, Gi0/5, Gi0/6, Gi0/7
254 Network-Mgmt active
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1 enet 100001 1500 - - - - - 0 0
4 enet 100004 1500 - - - - - 0 0
31 enet 100031 1500 - - - - - 0 0
200 enet 100200 1500 - - - - - 0 0
239 enet 100239 1500 - - - - - 0 0
254 enet 100254 1500 - - - - - 0 0
1002 fddi 101002 1500 - - - - - 0 0
1003 tr 101003 1500 - - - - - 0 0
1004 fdnet 101004 1500 - - - ieee - 0 0
1005 trnet 101005 1500 - - - ibm - 0 0


Primary Secondary Type Ports
------- --------- ----------------- ------------------------------------------

Loc1-3560cg#sh int Gi0/7
GigabitEthernet0/7 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is bcc4.93c2.0745 (bia bcc4.93c2.0787)
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)
Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 1000 bits/sec, 2 packets/sec
20974 packets input, 7029897 bytes, 0 no buffer
Received 1277 broadcasts (1048 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 1048 multicast, 0 pause input
0 input packets with dribble condition detected
53977 packets output, 35988613 bytes, 0 underruns
0 output errors, 0 collisions, 1 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


Also, do I need to add VLAN 31 to every switch along the path or is allowing it through the trunk ports enough?


10 Replies 10

MHM Cisco World

share the 
show vtp status 
show mac-address table

I don't have it plugged into the port at the moment, but even then sh mac-address-table won't deliver any output on any of my switches. I have to do sh mac ad dy, and then it will show the mac, but it does show it. I guess my question would be, why are we looking at mac addresses and not the VLAN? I'm thinking the VLAN is the issue.

Loc1-3560cg#sh mac-address-table


% Invalid input detected at '^' marker.


Loc1-3560cg#sh vtp status

VTP Version capable             : 1 to 3

VTP version running             : 1

VTP Domain Name                 : thevtp

VTP Pruning Mode                : Disabled

VTP Traps Generation            : Disabled

Device ID                       : bcc4.93c2.0780

Configuration last modified by at 0-0-00 00:00:00


Feature VLAN:


VTP Operating Mode                : Transparent

Maximum VLANs supported locally   : 1005

Number of existing VLANs          : 10

Configuration Revision            : 0

MD5 digest                        : 0x6A 0xE7 0x6C 0xA3 0x40 0x34 0x92 0x8B

                                    0x34 0x0B 0xBB 0x05 0xD2 0xC6 0x68 0x9C


what is the VTP status of the switch where the printer is connected to, is that either a client or a server switch ? Make sure it is, because otherwise, the Vlan has only local significance. The best setup is to chose one switch to be the VTP server, and all others to be VTP clients (use VTP version 3 for security).

MHM Cisco World

Also, do I need to add VLAN 31 to every switch along the path or is allowing it through the trunk ports enough?

You get the answer for your issue, you need to add VLAN and allow it in trunk.
also check the VTP is transparent mode

VTP is in transparent mode and I have allowed the VLAN through the trunk ports. But do I need to add it somewhere else besides the trunk ports on each switch in the path? 

Yes only when assign VLAN to access port the VLAN is add automatic but for trunk NO when you allow it the SW not add it you need to add it.

So what you're saying is (if I understand correctly) is that even though I've allowed the VLAN through the trunk ports, I still need to add it to an access port on every switch on the path? 

one each SW that the traffic is bridge until it routed,
what I meaning if
if the SVI of VLAN 31 is in SW3 then the 
VLAN must add in SW1 SW2 SW3


if the SVI of VLAN 31 is in SW2 
only SW1 and SW2 need to add VLAN, 
in SW2 the frame will routed to other VLAN so in SW3 no need VLAN 3.

OK, I've got VLAN 31 on every switch back to the mdf. I'll let you know later if this works; I have to run back out to the site. 

good job friend.

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