Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual page 1185

Understanding Link Aggregation into an EX8200 Virtual Chassis
Related
Documentation
Understanding Global Management of an EX8200 Virtual Chassis
Copyright © 2010, Juniper Networks, Inc.
Chapter 44: EX8200 Virtual Chassis—Overview, Components, and Configurations
Configuring Aggregated Ethernet Interfaces (CLI Procedure) on page 1330
An EX8200 Virtual Chassis is typically used to aggregate standalone EX8200 switches
at the distribution layer into a Virtual Chassis. The advantages of connecting multiple
EX8200 switches into a Virtual Chassis include better managed bandwidth at a network
layer, simplified configuration and maintenance because multiple devices can be managed
as a single device, and a simplified Layer 2 network topology that minimizes or eliminates
the need for loop prevention protocols such as Spanning Tree Protocol (STP).
You can extend the benefits of a network using an EX8200 Virtual Chassis at the
distribution layer by configuring the network connections of the devices connecting to
the EX8200 Virtual Chassis as link aggregation group (LAG) bundles. A LAG balances
traffic across the member links within an aggregated Ethernet bundle and effectively
increases the uplink bandwidth of network traffic into the Virtual Chassis. An EX8200
Virtual Chassis can support up to 239 LAGs and up to 12 interfaces per LAG. Member
links of a single LAG can span between multiple switches that are part of the same
EX8200 Virtual Chassis.
Configuring LAGs into the Virtual Chassis minimizes the need for spanning-tree protocols
by bundling multiple interfaces into a single interface. Another advantage of link
aggregation is increased link availability compared to that of links not configured in LAGs.
Because the LAG is composed of multiple member links, the LAG continues to carry
traffic over the remaining links when a link fails.
Link aggregation is also useful for combining Virtual Chassis Ports (VCPs) within an
EX8200 Virtual Chassis. See "Understanding Virtual Chassis Port Link Aggregation in an
EX8200 Virtual Chassis" on page 1080.
EX8200 Virtual Chassis Overview on page 1071
An EX8200 Virtual Chassis is composed of two EX8200 switches and up to two XRE200
External Routing Engines, so it has up to four console (
out-of-band management (
ports are accessible through the network; the EX8200 switch management ports are
connected to the external Routing Engines.
You can configure an EX8200 Virtual Chassis by logging in to the out-of-band
management ( MGMT ) port or to the console (
Engine.
If you log in to the backup external Routing Engine or in to a member switch and want to
configure the EX8200 Virtual Chassis, either cancel your session and log in to the master
external Routing Engine or enter the
session to the master external Routing Engine.
CON
MGMT ) ports. The XRE200 External Routing Engines MGMT
CON ) port of the master external Routing
request session member
) ports and up to two accessible
statement to redirect your
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