Extreme Networks Px Series Persistence Modes, 1Scheduling Policies, Specifier Policy Description

The Px series application switch supports the following scheduling policies:

Table 6-1:Scheduling Policies

Specifier	Policy	Description
rr	round robin	Distributes clients evenly across the web server group by passing each
		new connection request to the next server in line. The first client
		connection is sent to the first server, the second to the second server,
		and so on, until each server has a connection. When each server has
		its first connection, the next client connection is sent to the first server,
		the next to the second, and so on.
		Round robin is the simplest way of balancing web traffic, and is best
		suited for environments where the performance level of all servers is
		about equal, and all servers provide the same content.
wrr	weighted	Similar to round robin, except that you can apply a weight to each
	round robin	server. For example, if server A has a weight of two, and server B has
		a weight of one, server A receives two connections for each connection
		given to server B.
		Weighted round robin is useful if all servers provide the same content,
		but some are faster than others.
lc	least	Passes a new connection to the server having the least number of
	connections	active sessions. It distributes clients based on the server with the least
		connections currently open.
		The least connections policy provides the best performance under most
		conditions.
wlc	weighted	As in weighted round robin, assigns a weight to each server. The weight
	least	can be based on a number of things, including:
	connections	■	Processor speed
		■	Network connection speed
		Connections are distributed using the servers with the least connections

by weight. As in weighted round robin, weighted least connections can be used if servers have very different connection handling capacities.

Weighted least connections has the advantage of not overloading older, slower servers with too many connections.

Persistence Modes

Persistence, also called stickiness, is the maintenance of a session between a client and a particular web server. Most medium- and large-scale websites have multiple, redundant web servers that are run in parallel and contain duplicate information. When a client

6-2 Px Series Application Switch Installation and Configuration Guide