Design help related to ACE to Switch connectivity using Port-Channel

[acharyr123]

Hi,

I have a Cisco ACE 4710 configured in One-Arm mode. This ACE is getting connected with 2 3750 switches. These 2 3750 switches connected in trunk mode.

ACE is connected to these 3750 switches using Port-channel.

ACE Config:

================================

interface gigabitEthernet 1/1

  description One-arm mode port to DMZ Switch 1 port 20

  channel-group 1

  no shutdown

interface gigabitEthernet 1/2

  description One-arm mode port to DMZ Switch 2 port 20

  channel-group 1

  no shutdown

interface port-channel 1

  switchport access vlan 51

  port-channel load-balance src-dst-ip

  no shutdown

interface vlan 51

  ip address 10.40.56.131 255.255.255.128

  access-group input everyone

  access-group output everyone

  nat-pool 1 10.40.56.215 10.40.56.215 netmask 255.255.255.255 pat

  service-policy input LB

  service-policy input remote-access

  no shutdown

===========================================================

The problem is that 3750 switches are not stacked.

Application is working fine. But i am getting a lot of MAC flapping messages..

kindly suggest whether this design is OK or something needs to be done to rectify it...

Attached a small diagram..

[jlamousn]

Hello acharyr123,

I don't think this design is ok, and it would cause mac flapping since the two indepedendent 3750 switches will learn the ace mac addresses off of two different interfaces.  The 3750s would have to be stacked so that they would act as one switch then this should work correctly.

Thanks

Joel Lamousnery

TAC CSE