04-25-2007 11:17 PM - edited 03-05-2019 03:41 PM
Hi all,
i have a core switch, 6509, and an edge switch, 2960,which i need to connect using 2 uplinks. whenever i do this, my network experiences a loop, and behavior is very shaky.
the 6509 is acting as STP root for all vlans, and the 2 ports connecting to the 2960 are:
interface GigabitEthernet9/1
description Imatco_2
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-1005,1024-4094
switchport mode trunk
no ip address
end
SW6509#sh run int g9/2
Building configuration...
Current configuration : 204 bytes
!
interface GigabitEthernet9/2
description Imatco_2
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-1005,1024-4094
switchport mode trunk
no ip address
shutdown
end
the 2960 interfaces are:
interface GigabitEthernet0/1
switchport trunk allowed vlan 1-1005,1024-4094
switchport mode trunk
end
interface GigabitEthernet0/2
switchport trunk allowed vlan 1-1005,1024-4094
switchport mode trunk
shutdown
end
what am i missing?
thanks.
04-25-2007 11:27 PM
Why do you need to connect 2 links between the switches ? What is the design you are setting up?
Do you have STP enabled on all the 4 ports. If you have STP enabled on all the 4 ports, STP will eventually block one of the port and there should be no loop in the network. Chec using " "show spanning-tree details " or "show spanning-tree summary "/ "show spanning-tree gig x/y "
If you have to connect the 2 links directly to 6500, I would suggest creating an ether-channel and bundle the ports together. This will give you enhanced bandwidth and also as per STP this is only a single virtual link. Both the ports will also forward the traffic simultaneously
-amit singh
04-25-2007 11:57 PM
Hi Amit,
actually i did try to create an etherchannel bundle, and i grouped the interfaces from both sides. The 6509 config i did is:
interface Port-channel13
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-1005,1024-4094
switchport mode trunk
no ip address
int g9/1 {and 9/2}
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1-1005,1024-4094
switchport mode trunk
no ip address
channel-group 13 mode on
on the 2960, i used:
interface Port-channel1
switchport mode trunk
interface GigabitEthernet0/1
switchport trunk allowed vlan 1-1005,1024-4094
switchport mode trunk
channel-group 1 mode on
!
interface GigabitEthernet0/2
switchport trunk allowed vlan 1-1005,1024-4094
switchport mode trunk
channel-group 1 mode on
and this is what actually caused the loop.
what do you think?
04-26-2007 01:45 AM
Config seems to be perfectly fine. We have same seetings on all the 4 ports.Please let me know the IOS version on 6500 and 2960's.
-amit singh
04-27-2007 06:40 AM
Hi Amit,
the 2960 is running c2960-lanbase-mz.122-25.SEE2; the 6509 is running s222-ipservices_wan-mz.122-18.SXF6.bin
what do you think?
-Mohamad.
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