How to avoid asymmetric routing when configuring HSRP?

have a question regarding HSRP, and how to avoid asymmetric routing.  I configured my two core switches (Cisco 3550-12G's) in HSRP as shown below:

Core SW1

spanning-tree vlan 1 priority 24576
spanning-tree vlan 20 priority 24576

interface Vlan1
 ip address 192.168.1.3 255.255.255.0
 no ip redirects
 standby 1 ip 192.168.1.1
 standby 1 priority 95
 standby 1 preempt delay minimum 180
 standby 1 authentication gabriel9
!
interface Vlan20
 ip address 192.168.12.203 255.255.255.0
 no ip redirects
 standby priority 95
 standby 20 ip 192.168.12.200
 standby 20 priority 95
 standby 20 preempt delay minimum 180
 standby 20 authentication gabriel9

Core SW2

spanning-tree vlan 1 priority 28672
spanning-tree vlan 20 priority 28672

interface Vlan1
 ip address 192.168.1.2 255.255.255.0
 no ip redirects
 standby 1 ip 192.168.1.1
 standby 1 priority 110
 standby 1 preempt delay minimum 180
 standby 1 authentication gabriel9
!
interface Vlan20
 ip address 192.168.12.202 255.255.255.0
 no ip redirects
 standby priority 110
 standby 20 ip 192.168.12.200
 standby 20 priority 110
 standby 20 preempt delay minimum 180
 standby 20 authentication gabriel9


I have a Cisco 3550-48 switch that hangs of the 3550-12G's.  One uplink port on the 3550-48 goes to Core SW1, and the other uplink port goes to Core SW2.  this switch is on vlan 20.  I have the following route statment on the 3550-48"

ip route 0.0.0.0 0.0.0.0 192.168.12.200 (standby IP on core switches)

How do I know what switch traffic is getting routed to?  Core SW1 or Core SW2?  I have set spanning-tree priority on the vlans as shown above.  I wasn't sure if that would accomplish it.  Then when traffic is coming back in from outside the network, how does it know what traffic to send to what core switch.  Any help would be greatly appreciated.  Thanks.
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denver218Asked:
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Craig BeckCommented:
For outbound traffic, whichever switch is the active router will forward traffic.  You can determine which one by issuing the show hsrp summary command.

For inbound traffic it will depend on how your internet link(s) is configured.
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denver218Author Commented:
show hsrp summary is not a command on the 3550-12G
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Craig BeckCommented:
Oops... try show standby brief

I honestly don't know where I got the last command from!?  Not enough coffee :-S
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denver218Author Commented:
I forgot to add my other VLAN that I have on the core switches:

CORE SW1
interface Vlan 30
 ip address 10.10.0.3 255.255.255.0
 no ip redirects
 standby priority 95
 standby 30 ip 10.10.0.1 255.255.255.0
 standby 30 priority 95
 standby 30 preempt delay minimum 180
 standby 30 authentication gabriel9


interface Vlan 30
 ip address 10.10.0.2 255.255.255.0
 no ip redirects
 standby priority 110
 standby 30 ip 10.10.0.1 255.255.255.0
 standby 30 priority 110
 standby 30 preempt delay minimum 180
 standby 30 authentication gabriel9

The 3550-48 I reference above is on vlan 30 (10.10.0.0/24)

My ASA5510 has a route inside statement:

route inside 10.10.0.0 255.255.255.0 192.168.12.200

So when traffic is coming back in, what 3550-12G is it coming back on.  My topology looks as follows:



ROUTER - connection to internet
    |
    |
ASA5510
    |
    |
Cisco 3550-24
    |
    |
Two Cisco 3550-12G in HSRP (each one has a link to the above switch
    |
    |
Cisco 3550-48 (10.10.0.0/24)
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Craig BeckCommented:
The traffic would come in to Core2 as the priority is higher.
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denver218Author Commented:
Ok thanks.  So traffic comes in on Core2, now for outgoing traffic this is the output from show standby brief on Core1:  If I'm reading this right traffic goes outbound via Core1?

3550CORE_SW1#show standby brief
                     P indicates configured to preempt.
                     |
Interface   Grp Prio P State    Active addr     Standby addr    Group addr
Vl1         1   110  P Active   local           192.168.1.3     192.168.1.1
Vl20        20  110  P Active   local           192.168.12.203  192.168.12.200
Vl30        30  110  P Active   local           10.10.0.3       10.10.0.1
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Craig BeckCommented:
Yes that looks like traffic goes via Core1.

However that doesn't look like it's configured as per the configs you posted earlier.  The config you posted suggests that Core1 has a priority of 95 for VLAN20, while Core2 has a priority of 110.  That would make Core2 the active router.
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denver218Author Commented:
Thanks
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