Understanding How The Master In An Ex4200 Virtual Chassis Is Elected; Understanding Software Upgrade In An Ex4200 Virtual Chassis - Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual

Complete Software Guide for Junos

Understanding How the Master in an EX4200 Virtual Chassis Is Elected

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Understanding Software Upgrade in an EX4200 Virtual Chassis

898
®
OS for EX Series Ethernet Switches, Release 10.4
All switches that are interconnected in an EX4200 Virtual Chassis configuration are
member switches of that Virtual Chassis. Each Virtual Chassis configuration has one
member that functions as the master and controls the Virtual Chassis configuration.
When a Virtual Chassis configuration boots, the Juniper Networks Junos operating system
(Junos OS) for Juniper Networks EX4200 Ethernet Switches automatically runs a master
election algorithm to determine which member switch takes the role of master.
The algorithm that the software uses to determine the master in an EX4200 Virtual
Chassis is as follows:
Choose the member with the highest user-configured mastership priority (255 is the
1.
highest possible value).
Choose the member that was master the last time the Virtual Chassis configuration
2.
booted.
Choose the member that has been included in the Virtual Chassis configuration for
3.
the longest period of time. (For this to be a deciding factor, there has to be a minimum
time lapse of one minute between the power-ons of the individual interconnected
member switches.)
Choose the member with the lowest MAC address.
4.
The variations among EX4200 switch models, such as whether the switch has 48 or 24
ports, do not impact the master election algorithm. To ensure that a specific member is
elected as the master:
Power on only the switch that you want to configure as master of the Virtual Chassis
1.
configuration.
Configure the mastership priority of that member to have the highest possible value
2.
(255).
Continue to configure other members through the master member, as desired.
3.
Power on the other members.
4.
EX4200 Virtual Chassis Overview on page 891
Understanding EX4200 Virtual Chassis Components on page 893
Understanding EX4200 Virtual Chassis Configuration on page 904
An EX4200 Virtual Chassis can be composed of multiple Juniper Networks EX4200
Ethernet Switches and each member switch is running Juniper Networks Junos operating
system (Junos OS) packages. For ease of management, the Virtual Chassis configuration
provides flexible methods to upgrade software releases.
Copyright © 2010, Juniper Networks, Inc.