Intel 1520 User Manual

Intel NetStructure Cache Appliance Administrator’s Guide

Setting Web management options

The Web Management section lets you restart the cluster and specify refresh rates 
as observed in monitor mode. The following table describes these configuration 
settings.

Setting virtual IP addressing options

The Virtual IP Addressing section lets you define and maintain the appliance’s 
pool of virtual IP addresses.

The appliance keeps a pool of IP addresses as virtual IP addresses from which to 
draw and assign IP addresses to nodes as necessary. This practice assures that if a 
node in the cluster fails, other nodes can assume the failed node’s responsibilities.

Virtual IP addresses are really just IP addresses. They are called virtual addresses 
because they are not tethered to particular machines and can rotate among nodes 
in a cluster.

It is common for a single machine to represent multiple IP addresses on the same 
subnet. This machine would have a primary or real IP address bound to its 
interface card and would also serve many more virtual addresses.

You can set up your user base to use a DNS round-robin pointing at virtual IP 
addresses, as opposed to using the real IP addresses of the appliance machines in 
the cluster.

Because virtual IP addresses are not bound to machines, a cluster can steal 
addresses from inactive nodes and distribute those addresses among the 
remaining live nodes. 

Using a proprietary management protocol, appliance nodes communicate their 
status with their peers. If a node fails, its peers notice the failure and quickly 
negotiate which of the remaining nodes will mask the fault by taking over the 
failed node’s virtual interface.