{"id":127,"date":"2016-08-13T00:44:13","date_gmt":"2016-08-12T22:44:13","guid":{"rendered":"http:\/\/hentati.org\/?p=127"},"modified":"2020-12-06T20:41:45","modified_gmt":"2020-12-06T19:41:45","slug":"f5-loadbalancer-gtm-vs-ltm-difference-between-global-local-traffic-manager","status":"publish","type":"post","link":"https:\/\/hentati.org\/index.php\/2016\/08\/13\/f5-loadbalancer-gtm-vs-ltm-difference-between-global-local-traffic-manager\/","title":{"rendered":"F5 (LoadBalancer) GTM VS LTM \u2013 DIFFERENCE BETWEEN GLOBAL & LOCAL TRAFFIC MANAGER"},"content":{"rendered":"

GTM \u2013 Global Traffic Manager Overview<\/span><\/h3>\n

The\u00a0Global Traffic Manager<\/strong>, aka\u00a0GTM<\/strong>, and now referred to\u00a0DNS<\/strong>, is one of the cutting edge modules offered on F5 Networks BIG-IP\u00ae platform. \u201cGlobal\u201d is the right word for this module because it has the ability to make name resolution load balancing decisions for systems located anywhere in the World, not just the US. You can think of the GTM as an intelligent DNS that is security minded. In other words its\u2019 logic can make informed decisions on correlating a hostname to an IP address while keeping security in check.<\/span><\/p>\n

Most things you do on the Internet or Private networks start with name resolution \u2013 so it makes sense if you\u2019re going to load balance an application it would start at this layer \u2013 resolving names to IPs based on availability, Performance, and even Persistence. It\u2019s important to note, traffic does not \u201croute\u201d through the GTM, the GTM simply tells you the best IP to route to based on metrics for the URL in question. That IP can be almost anything really, but usually it\u2019s an actual server, or a virtual IP that fronts multiple servers. Like a traditional DNS architecture you usually have multiple GTMs in your architecture, this is for redundancy\/availability.<\/span><\/p>\n

The main configuration element in a GTM is called a Wide IP or WIP for short, or as my significant other likes to call it a \u201cWipey\u201d ;). There are many configuration elements that work in concert with a WIP, but at the base of it all is the Wide IP. A WIP equates to the common URL you\u2019re load balancing, for example www.yourcompany.com. A pool or pools are usually attached to a WIP which contain the IPs it\u2019s intelligently resolving. Like your run of the mill DNS server, the GTM does not tell the requester any information about ports. Though, the monitors associated with the pool members can indeed monitor availability or performance on ports.<\/span><\/p>\n

 <\/p>\n

LTM \u2013 Local Traffic Manager Overview<\/span><\/h3>\n

The\u00a0Local Traffic Manager<\/strong>, aka\u00a0LTM<\/strong>, is the most popular module offered on F5 Networks BiG-IP\u00ae platform. The real power of the LTM is it\u2019s a Full Proxy, allowing you to augment client and server side connections. All while making informed load balancing decisions on availability, performance, and persistence. \u201cLocal\u201d in the name is important, opposed to the GTM, traffic actually flows through the LTM to the servers it balances traffic to. Usually the servers it\u2019s load balancing sit \u201clocally\u201d in the same data center as the LTM, though that is not a requirement. With SNAT configured on the VIP, if you can route to it you can load balance it \u2013 so it\u2019s possible to have servers in different data centers be a part of the same pool in an LTM VIP.<\/span><\/p>\n

The main configuration element on an LTM is the Virtual IP or VIP for short. There are a plethora of configuration elements that work with VIPs, but at the heart of the technology it\u2019s a VIP they are all a part of. Like a WIP, VIPs equate to the URL you\u2019re load balancing, but at its lowest level. Like a WIP it usually contains a pool with the servers it\u2019s load balancing & monitor(s) to measure availability \/ performance.<\/span><\/p>\n

Some of the Key differences of the GTM vs LTM<\/span><\/p>\n

    \n
  • The biggest difference between the GTM and LTM, as mentioned earlier, is traffic doesn\u2019t actually flow through the GTM to your servers.<\/span><\/li>\n
  • The GTM is an intelligent name resolver, intelligently resolving names to IP addresses.<\/span><\/li>\n
  • Once the GTM provides you with an IP to route to you\u2019re done with the GTM until you ask it to resolve another name for you.<\/span><\/li>\n
  • Similar to a usual DNS server, the GTM does not provide any port information in its resolution.<\/span><\/li>\n
  • The LTM doesn\u2019t do any name resolution and assumes a DNS decision has already been made.<\/span><\/li>\n
  • When traffic is directed to the LTM traffic flows directly through its\u2019 full proxy architecture to the servers it\u2019s load balancing.<\/span><\/li>\n
  • Since the LTM is a full proxy it\u2019s easy for it to listen on one port but direct traffic to multiple hosts listening on any port specified.<\/span><\/li>\n<\/ul>\n

     <\/p>\n

    How do the GTM & LTM work together?<\/span><\/h3>\n

    The GTM and LTM can work together or they can be totally independent. If your organization owns both modules it\u2019s usually using them together, and that\u2019s where the real power comes in.. They do this via a proprietary protocol called iQuery. iQuery, functioning on TCP port 4353, reports VIP availability \/ performance back to the GTMs. The GTMs can then dynamically resolve VIPs that live on an LTM(s).<\/span><\/p>\n

    When a GTM has LTMs as servers in its\u2019 configuration there is no need to monitor the actual VIP(s) with application monitors, as the LTM is doing that & iQuery reports the information back to the GTM.<\/span><\/p>\n

    As you can see the GTM & LTM modules are powerful tools in the world of Application Delivery \/ Load Balancing. Together the GTM & LTM make one mean lean Application Delivery machine.<\/em><\/span>
    \nQuestions? Comments? Or would like to share how your organization is using the LTM & GTM module? Well Chime right in below!<\/em><\/span><\/p>\n

     <\/p>\n","protected":false},"excerpt":{"rendered":"

    GTM \u2013 Global Traffic Manager Overview The\u00a0Global Traffic Manager, aka\u00a0GTM, and now referred to\u00a0DNS, is one of the cutting edge modules offered on F5 Networks BIG-IP\u00ae platform. \u201cGlobal\u201d is the …<\/p>\n","protected":false},"author":1,"featured_media":192,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6],"tags":[],"_links":{"self":[{"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/posts\/127"}],"collection":[{"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/comments?post=127"}],"version-history":[{"count":3,"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/posts\/127\/revisions"}],"predecessor-version":[{"id":632,"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/posts\/127\/revisions\/632"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/media\/192"}],"wp:attachment":[{"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/media?parent=127"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/categories?post=127"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hentati.org\/index.php\/wp-json\/wp\/v2\/tags?post=127"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}