Cabletron Systems 9032578-05 manual Persistence Default Binding Level Timeout, Sticky Minutes

Chapter 17: Web Hosting Configuration Guide

directed to the same load balancing server (for example, the server with IP address 10.1.1.1).

•Sticky persistence: a binding is determined by matching the source and destination IP addresses only. This allows all requests from a client to the same virtual address to be directed to the same load balancing server. For example, both HTTP and HTTPS requests from the client address 134.141.176.10 to the virtual destination address 207.135.89.16 would be directed to the same load balancing server (for example, the server with IP address 10.1.1.1).

•Virtual private network (VPN) persistence: for VPN traffic using Encapsulated Security Payload (ESP) mode of IPSec, a binding is determined by matching the source and destination IP addresses in the secure key transfer request to subsequent client requests. This allows both the secure key transfer and subsequent data traffic from a particular client to be directed to the same load balancing server. The default port number recognized by the SSR for secure key transfer in VPN is 500; you can use the load-balance set vpn-dest-portcommand to specify a different port number.

You can use the load-balance show source-mappingscommand to display information about the current list of bindings.

The binding between a client (source) and a load balancing server times out after a certain period of non-activity. The default timeout depends upon the session persistence level configured, as shown below:

Persistence	Default Binding
Level	Timeout
TCP	3 minutes
SSL	120 minutes
Sticky	120 minutes
VPN	3 minutes

You can change the timeout for a load balancing group with the load-balance set aging- for-src-mapscommand.

The SSR also supports netmask persistence, which can be used with any of the four levels of session persistence. A netmask (configured with the load-balance set client-proxy-subnetcommand) is applied to the source IP address and this address is compared to the list of bindings: if a binding exists, the packet is sent to the same load balancing server previously selected for this client; if there is not a match, a new binding is created. This feature allows a range of source IP addresses (with different port numbers) to be sent to the same load balancing server. This is useful where client requests may go through a proxy that uses Network Address Translation or Port Address Translation or multiple proxy servers. During a session, the source IP address can change to one of several sequential addresses in the translation pool; the netmask allows client requests to be sent to the same server.

234 SmartSwitch Router User Reference Manual