How Load balancing and Routing works in Netscaler

Load Balancing Work Flow

Load balancing traffic flow is an important information before start learning netscaler load balancing. So here i am going start with VIP which means virtual ip. This VIP represents the public IP which we assign within virtual server created under netscaler. We can create multiple virtual servers which represents multiple public IP's having there entry over public DNS so that user request can come to netscaler. Once request reach netscaler that route to SNIP(subnet ip), here SNIP represent to an network IP of same zone under which set of application server resides. there can be multiple SNIP's as well under netscaler. so how request flow is intially request comes from public user to VIP and then route to SNIP and after load calculation and monitor status as per assigned policy request reach to application server. For reverse response same mechanism getting followed.

                                                     How we can do Static Routing

SNIP: As we know that mostly net scaler resides in DMZ and used to forward traffic to multiple networks so we need to enable default routing on netscaler by adding USNIP (Use Subnet IP). For example there is one one request came and want to route toward 24 bit network 192.168.1.* then we add the SNIP on net scaler for the same. After adding that netscaler start packet forwarding towards 192.168.1.* subnet. To add that we need to go to NS  then system then network then IP's then IPv4 and click on add button for adding subnet address.

After clicking give the Subnet IP address and select option of IP Type as subnetIP. Here we need to keep in mind that we should restrict some important options like telnet which send information in clear text and FTP which is not secure then click on create. That's it your routing is configured.

MIP(Mapped IP Adress): In some cases we can see that direct reachability to some network is not possible but there there is an internal router available using which traffic can route to that network. In that case we define static route which will forward traffic to that internal router which is allowed to route traffic towards directly restricted network from NS. For example we have some request which need to reach 23.3.3.X network segment but direct reachability from netscaler is restricted to that network but there is an internal router with IP 13.3.3.3 which is configured to route traffic to 23.3.3.X network. In this case we create MIP which will be used to route traffic to that network. Here one point need to be taken care that at least one SNIP of 13.3.3.X should be present so that NS traffic can reach to all devices to that network. Now NS can easily reach to internal router and use that as gateway for all traffic which need to route towards 23.3.3.X network. 

To configure that go to Netscaler  then System then Networks then Routs then Basic and after that click on add. New window for route creation will appear and fill the details as per example and click on create. You can use screenshot for reference, 

Hurry!!!!!Now MIP is configured.