Dear All,
I have this network scenario in my Lan:
In the rack1 there are two cisco 3750-48TS connected among them via stack-wise cable than via the giga port the stack master is connected to the stack master of another stack composed by two 3750-48TS in the rack2.
The Stack member in the rack1 is connected to the other stack member in the rack2
In the rack1 is connected to the 3750 the primary router that link my site to a MPLS Wan.
In the rack2 is connected the backup router to the 3750,that is connected via ISDN to the same MPLS Wan of the primary router.
I have created a Management Vlan where all the router/switch are connected, and another Vlan called Ro_Wan for the Routers that link my site to the MPLS Wan, finally I’ve created a User Vlan.
I have configured HSRP in the User Vlan among the stack in the rack1 and the other in the rack2 to provide resiliency for the PCs ,also I have configured HSRP in the Ro_Wan Vlan among the stack in the rack1 and the stack in the rack2 to use the virtual ip address as next hop for the routing-back in the routers configuration.
My question is:
If both the two giga links among the rack1 and the rack2 goes down,the stack in the rack2 become Active so the traffic generated by the PCs makes the backup line up but the primary link is up too with the same network connected on the Lan, how I can avoid this problem ?
