Datasheet

4
Virtual Chassis Technology
TheEX8208supportsJuniperNetworks’uniqueVirtualChassis
technology, which enables two interconnected EX8200 chassis—
any combination of EX8208s or EX8216s—to operate as a single,
logical device with a single IP address. Deployed as a collapsed
aggregationorcorelayersolution,anEX8200VirtualChassis
configuration creates a network fabric for interconnecting access
switches, routers, and service-layer devices such as firewalls and
load balancers using standards-based Ethernet LAGs.
InaVirtualChassisconfiguration,EX8200switchescanbe
interconnected using either single line-rate 10GbE links or a LAG
withupto1210GbEline-ratelinks.SincetheVirtualChassisintra-
connectionsusesmallformSFP+interfaces,VirtualChassis
member switches can be separated by distances of up to 40 km.
IftheEX8200VirtualChassisswitchmembersarelocatedinthe
same or adjacent racks, low cost direct attach cables (DACs) can
be used as the interconnect mechanism.
SincethenetworkfabriccreatedbyanEX8200VirtualChassis
configuration prevents loops, it eliminates the need for protocols
such as Spanning Tree. The fabric also simplifies the network
byeliminatingtheneedforVirtualRouterRedundancyProtocol
(VRRP),increasingthescalabilityofthenetworkdesign.In
addition,sincetheVirtualChassisControlProtocol(VCCP)used
toformtheEX8200VirtualChassisconfigurationdoesnotaffect
the function of the control plane, Junos OS control plane protocols
such as 802.3ad, OSPF, Internet Group Management Protocol
(IGMP), Physical Interface Module (PIM), BGP and others running
onanEX8200VirtualChassissystembehaveinexactlythesame
way as when running on a standalone chassis.
EX8200VirtualChassisconfigurationsarehighlyresilient,withno
single point of failure, ensuring that no single element—whether a
chassis, a line card, a Routing Engine, or an interconnection—can
rendertheentirefabricinoperablefollowingafailure.Virtual
Chassis technology also makes server virtualization at scale
feasible by providing simple L2 connectivity over a very large pool
of compute resources located anywhere within a data center.
VirtualChassistechnologycanalsobeusedtoextendEX8200-
basedVLANsbetweendatacentersbyplacinganequalnumberof
switches in both data centers, or by interconnecting two separate
VirtualChassisconfigurationsusingasimpleL2trunk.
XRE200 External Routing Engine
InanEX8200VirtualChassisconfiguration,theRoutingEngine
functionality is externalized to a purpose-built, server-class
appliance, the XRE200, which supports control plane processing
requirements for large-scale systems and provides an extra layer
of availability and redundancy.
All control protocols such as OSPF, IGMP, Link Aggregation Control
Protocol(LACP),802.3ahandVCCP,aswellasallmanagement
plane functions, run or reside on the XRE200. Junos OS high
availability (HA) features can be enabled on the two XRE200s
requiredinaredundantEX8200VirtualChassisconfiguration.In
the event of an active XRE200 failure, the standby XRE200 takes
overandJunosOSHAfeaturesensurethatthestateoftheVirtual
Chassis, L2/L3 protocols, and forwarding information are not lost.
See the XRE200 data sheet for more information.
Virtual Chassis
Access
Configurations
EX8208 EX8208
EX4200 EX4200 EX4200 EX4200 EX4200
Figure2:TheEX8208canaggregateVirtualChassiscongurationswithinasingleplatformtoprovidehigh-performance,
line-rate connectivity to upstream devices.