Disclaimer: I know a bit about Cisco switches, but I will be the first to admit that there is a LOT that I do not know. So, please bear with me with something that may be a very long description of what ends up being a very simplistic issue.
I have a stack which consists of 3 C2960 switches that are being replaced with 3 C9200 switches. I have the stack configured so that both stacks are basically identical, with changes being made to the IP addresses and such to avoid any conflicts while I am migrating.
For the most part (or at least from what I can tell) everything is working as it should. Port VLAN assignments (access mode) are working just fine, traffic is passing between VLANs without issue, etc. However, I am running into an issue when I connect a managed switch into the port I have configured for it.
The switch that I am connecting is a Netgear GS350 8-Port Managed Switch. There are 3 different VLANs set up on the switch:
- ID 10 - Servers
- ID 26 - Printers
- ID 251 - Network Management
That device works exactly as intended. I can ping it, log into the network management interface, etc. The devices connected to the ports assigned as VLAN10 and 26 are working fine. This tells me that the Netgear switch is configured properly.
That switch is connected to GI2/0/8 on the existing C2960 stack, and I have that same port configured to match on my new C9200 stack. Here is the config for that port:
Existing Stack:
interface GigabitEthernet2/0/8
description Managed Switch - IT Office
switchport trunk native vlan 251
switchport trunk allowed vlan 10,26,251
switchport mode trunk
spanning-tree portfast trunk
end
New Stack:
interface GigabitEthernet2/0/8
description Managed Switch - IT Office
switchport trunk native vlan 251
switchport trunk allowed vlan 10,26,251
switchport mode trunk
spanning-tree portfast trunk
end
When I move the cable from 2/0/8 on the old/existing stack to the new stack, everything works as expected for all of the devices connected on there on VLANs 10 and 26, however I am unable to communicate with the Netgear switch on VLAN251. I know the switch is there, because I can talk to the devices beyond it.
When I look at the mac address-table for that port, it shows the devices and VLANs:
CORE-STACK#show mac address-table int Gi2/0/8
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
251 2880.88df.835b DYNAMIC Gi2/0/8
10 0018.ae90.b510 DYNAMIC Gi2/0/8
10 f8bc.4100.485b DYNAMIC Gi2/0/8
26 0017.c880.0822 DYNAMIC Gi2/0/8
Total Mac Addresses for this criterion: 4The device on VLAN 251 is the switch.
Looking at the VLAN config on both switches, they are also identical:
interface Vlan251
ip address 172.16.251.50 255.255.255.0
end
It isn't that complicated of an interface :)
The ONLY thing that I can see different between the two switches is when I do a 'sh vlan'.
Old (Existing) stack:
CORE-SWITCH#sh vlan br
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Gi2/0/2, Gi2/0/8, Gi2/0/47
Gi2/0/50, Gi3/0/49, Gi3/0/50
Gi3/0/51, Gi3/0/52New Stack:
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Gi1/0/40, Gi1/0/42, Te1/1/2
Te1/1/3, Te1/1/4, Gi2/0/2
Gi2/0/40, Gi2/0/42, Gi2/0/47
Gi2/0/48, Gi2/1/1, Gi2/1/2
Gi2/1/3, Gi2/1/4, Gi3/0/2
Gi3/0/20, Gi3/0/40, Gi3/0/42
Gi3/1/1, Gi3/1/2, Gi3/1/3
Gi3/1/4I truncated everything after VLAN 1, mainly due to the remaining VLANs having the same issue (the ports listed for each vlan are widly different between the 2 stacks)
The new stack has more interfaces in VLAN 1, even though the configuration for each interface is exactly the same on both setups. This may be because I only have 3 ports occupied on the new stack (Gi2/0/8 for the Netgear switch, GI2/0/21 for my computer, and Te1/1/1 [switchport mode trunk] for the uplink to the rest of the network). Or, it could be for a myriad of other reasons that I am not aware of.
I have attached the config for each stack to this as well, as there is a very good chance that there is something that I am simply overlooking.
Does anyone have any ideas what I may be overlooking? I am absolutely stumped at this point.
