09-16-2010 07:40 AM - edited 03-06-2019 01:01 PM
Hi
We are currently facing a weird situation. We installed a new cisco switch 2960 lets call it Switch_floor_2 as in the below diagram
Core_switch --> Switch_floor_1--> Switch_floor_2
After the installation we were unable to telnet to the switch using its management IP. Precisely out of 10 Icmp Echo Requests we are getting only 1-2 replies.
The weird thing is that the Core_switch is learning the mac-address of the management IP of Switch_floor_2 from 2 vlans.
The one is the management vlan (Vlan 500) and the other is the vlan we are using for our Riverbed devices (VLAN 700).
In Switch_floor_2 there is nothing connected except the trunk link with Switch_floor_1.
Core_switch#show mac-address-table | include a8c1
* 700 xxxx.xxxx.a8c1 dynamic Yes 0 Fa3/11
* 500 xxxx.xxxx.a8c1 dynamic Yes 0 Gi4/5
(xxxx.xxxx.a8c1 is the mac-address of management interface vlan in Switch_floor_2 )
Is there a possibility of a duplicate mac-address in our network?
09-16-2010 07:46 AM
akisbouza wrote:
Hi
We are currently facing a weird situation. We installed a new cisco switch 2960 lets call it Switch_floor_2 as in the below diagram
Core_switch --> Switch_floor_1--> Switch_floor_2
After the installation we were unable to telnet to the switch using its management IP. Precisely out of 10 Icmp Echo Requests we are getting only 1-2 replies.
The weird thing is that the Core_switch is learning the mac-address of the management IP of Switch_floor_2 from 2 vlans.
The one is the management vlan (Vlan 500) and the other is the vlan we are using for our Riverbed devices (VLAN 700).
In Switch_floor_2 there is nothing connected except the trunk link with Switch_floor_1.
Core_switch#show mac-address-table | include a8c1
* 700 xxxx.xxxx.a8c1 dynamic Yes 0 Fa3/11
* 500 xxxx.xxxx.a8c1 dynamic Yes 0 Gi4/5(xxxx.xxxx.a8c1 is the mac-address of management interface vlan in Switch_floor_2 )
Is there a possibility of a duplicate mac-address in our network?
What are fa3/11 and gi4/5 connected to ?
Jon
09-16-2010 07:57 AM
Jon thanks for answering.
Port Gi4/5 is the one connecting Core_Switch with Switch_floor_1
Port Fa3/11 is the Riverbed_Wan port between our two sites.
I suppose the Riverbed is working like this
Site 1 Site 2
Core_Switch (Fa3/11) --> Riverbed_Interface_Site1 --> Riverbed_Interface_Site2 --> Core_Switch_Site_2
Akis
09-16-2010 08:01 AM
What do the arp tables show on the core switches for that mac-address.
Also do you need vlan 700 on the trunk links from the core switch to switch_floor_1 to switch_floor_2. If not it may be an idea to remove that vlan from the trunk links.
Jon
09-16-2010 08:43 AM
Core_Switch#show arp | include x.x.x.104
Internet x.x.x.104 30 xxxx.xxxx.a8c1 ARPA Vlan500
The arp table in the Core_Switch seems to be fine.
I have already tried removing vlan 700 from all trunk links but no result,
The intermediate switch_floor_1 is a WS-C2924M-XL and had 1 module WS-X2931-XL. Since i installed the second module WS-X2931-XL in order to connect it with the switch_floor_2 i havent done a reset in the switch_floor_1.
Maybe i ll try a reload and will let you know.
Thanks
09-16-2010 09:23 AM
The reload of the intermediate switch fixed the problem.
So when installing WS-X2931-XL modules in a WS-C2924M-XL always reload as weird things happen..
Jon thanks a lot
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