Datasheet

5
Architecture and Key Components
The EX8200 line of Ethernet switches feature a number of distinct
architectural elements. The Routing Engine on the SRE module runs
Junos OS, which processes all Layer 2 and Layer 3 protocols and
manages individual chassis components, while the Switch Fabric
module provides the central crossbar matrix through which all data
traffic passes. The SRE and Switch Fabric modules work together to
fulfill all Routing Engine and Switch Fabric functions.
The EX8200 line cards include ASIC-based packet forwarding
engines—the EX-PFE2— that process network traffic at wire
rate, as well as a line-card processor that provides scalable local
control and status processing. The EX8208 chassis backplane
distributes the data, control, and management plane signals
over independent paths to the various system components and
distributes power throughout the system. The fan tray provides
cooling to the line cards and control modules with redundant
variable-speed fans, while the power supplies convert building
power to the internal voltage required by the system.
All EX8208 components are hot-swappable, and all central
functions are available in redundant configurations, providing high
operational availability by allowing continuous system operation
during maintenance or repairs.
Switch Fabric and Routing Engine (SRE) Module
The EX8208 SRE module performs two functions: it incorporates
switch fabric, control plane, and management plane functionality
on a single module, and it includes an integrated Routing Engine
featuring a 1.2 GHz processor with 2 gigabytes of DRAM and 2
gigabytes of Flash storage. A dedicated front-panel RJ-45 Gigabit
Ethernet port on the SRE module supports out-of-band system
management and monitoring, while an external USB port allows
easy uploading and storage of software images, configuration
files, and logs. Direct console access is available through a
dedicatedserialport;anauxiliaryconsoleinterfacecansupport
remote modem access to the switch.
The Routing Engine on the SRE module is based on the field-
proven hardware architecture used by Juniper Networks routers,
bringing the same carrier-class performance and reliability to
the EX8208 that Juniper’s routers provide to the world’s largest
service provider networks. The Routing Engine’s central CPU
performs all system control functions and maintains the hardware
forwarding table and routing protocol states for the EX8208
switch. Dedicated hardware on the SRE module supports chassis
management functions such as environmental monitoring, while
communication between SRE modules and individual EX8200 line
cards takes place over a dedicated internal Gigabit Ethernet out-
of-band control interface.
EX8208 Switch Fabric
The switch fabric for the EX8208 switch, which serves as the
central non-blocking matrix through which all network data
passes, is distributed across three elements: the dual-redundant
SRE modules and the dedicated Switch Fabric module. Working
together, the SRE and Switch Fabric modules deliver the
necessaryswitchingcapacityfortheEX8208switch;whenthe
second SRE module is present, the additional switch fabric serves
in hot-standby mode, providing full 2+1 switch fabric redundancy.
The Switch Fabric modules are hot-swappable and field-
replaceable, enabling failed units to be easily replaced without
service interruption.
The two active, load-sharing switch fabrics on the SRE and Switch
Fabric modules collectively deliver up to 320 Gbps (full-duplex)
of packet-data bandwidth per line-card slot, providing sufficient
capacity to support future 100-Gigabit Ethernet deployments.
The EX8208 switch backplane is designed to support a maximum
fabric bandwidth of 6.2 Tbps.