Forum Discussion

jason_ives_4071's avatar
jason_ives_4071
Icon for Nimbostratus rankNimbostratus
Jul 29, 2008

GTM/LTM functioning as a LinkController

Hi,

 

 

I read somewhere that if you had the GTM and LTM modules installed on the same unit then you could achieve the same functionality as a link-controller (if not more).

 

 

I Have a V9 GTM with LTM installed, and would like to load balance both inbound/outbound sessions over multiple ISP links.

 

 

Does this sound feasible and is it straight forward to setup without the presence of the Link controller module.
config
design
  • Deb_Allen_18's avatar
    Deb_Allen_18
    Historic F5 Account
    Jul 29, 2008
    Yes, and yes, and yes you do get more. And less.

     

     

    When you install the LTM w/GTM module, you get the "Links" menu option just like Link Controller, so you can configure according to the LC manual, with one exception, IIRC: You can use the standard LTM load balancing options only. The cost based link load balancing options are ONLY avail with a real LC license, not the LTM/GTM combo.

     

     

    So you get all LTM & GTM features, many of which are not avail in LC (L7 iRules, more monitoring options, etc) but not all of the LC load balancing options.

     

     

    Click here for LC doc

     

     

    HTH

     

    /deb
  • JRahm's avatar
    JRahm
    Icon for Admin rankAdmin
    Jul 29, 2008
    Yes, and yes, and yes you do get more. And less.

     

     

    Very Seussian.
  • jason_ives_4071's avatar
    jason_ives_4071
    Icon for Nimbostratus rankNimbostratus
    Jul 30, 2008
    Thanks for the Info guys, much apprecited.

     

     

    One last query.....

     

     

    If I wanted to do inbound loadbalacning accross multiple ISP links for a given Wideip I would need to

     

     

    1. setup the wide ip

     

    2. create a virtual server per ISP network range

     

     

     

    Where it starts to get cloudy is how I tie the Links to the wideIP/virtual Svrs. Do I need to configure some dependecies within the Distibuted applications tab?.

     

     

    How would The LTM/GTM idenify that a link has gone down and to stop issuing DNS replies for those resources.?
  • dennypayne's avatar
    dennypayne
    Icon for Employee rankEmployee
    Jul 31, 2008
    When you create the WideIP you will associate the virtual servers with it, so LC will know which link to use because it knows which network range is assigned to which link.

     

     

    You need some sort of health monitor on the links, I typically use either a transparent ping to some known hop outside the border router (maybe even several that hit Google, Yahoo, etc and require at least one to be up) or SNMP to the router. If the health monitor fails, the link will be marked down and the associated virtuals will no longer be handed out for the WideIP.

     

     

    Denny