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luigi_avella_10's avatar
luigi_avella_10
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Dec 20, 2012

Network topology

Hi,

 

I have to shape the network to offer business continuity for several webservices and I thought about two options:

 

1) Using a GTM, but I have too few network interfaces

 

2) using an LTM to switch services between two Data Center (For business continuity), particularly the pool members will be VIP from the other LTM (each one situated in a different Data Center) all in the same extended VLAN.

 

So my questions are:

 

a) Does a module exist to expand network interfaces on GTM?

 

b) Has anyone ever used the 2) topology? Could it present problems?

 

 

Thank you

 

config
design

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  • luigi_avella_10's avatar
    luigi_avella_10
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    Apr 10, 2014

    It's a good Idea, but the application on N2 uses the external address and I can't change it. Anyway this Idea could be useful in other situations, thank you thousand.

     

  • Elias_O_16228's avatar
    Elias_O_16228
    Icon for Nimbostratus rankNimbostratus
    Apr 10, 2014

    Hi I have implemented a similar scenario as you described on your diagram.

     

    option 1: PBR on R1 and R2 is to police the traffic from R2 to LTM 172.23.2.1/24, and configure SNAT on LTM. SNAT is required if the pool member is not using LTM as gateway.

     

    option 2: Implement static route on R1 and R2 to statically route traffic to 172.23.2.x/24

     

    Then because N2 172.23.3.4/24 network with gateway is 172.23.3.1, you must have static route on the N2 server to return traffic back to LTM.

     

    Elias

     

  • luigi_avella_10's avatar
    luigi_avella_10
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    Apr 15, 2014

    Hi Elias, In first instance I would implement option 1, but finally I decided to use a PAT on R3, which is a cisco ASA, using the LTM VIP (10.254.34.25) like translation address. It's the simpliest solution because it doesn't imply routing changes neither on the nodes nor on the routers or LTM, however it will generate asymmetric traffic.