Switch Control Board Srx5K-Scb4 Overview - Juniper SRX5600 Hardware Manual

Switch Control Board SRX5K-SCB4 Overview

The SRX5K-SCB4 (SCB4) Enhanced Switch Control Board provides improved fabric performance and
bandwidth capabilities for high-capacity line cards using the ZF-based switch fabric. The SCB4 is supported
on SRX5600, and SRX5800 Services Gateways, but not supported on SRX5400 Services Gateways.
The SCB4 supports the standard and the enhanced midplane.
Some key attributes of the SCB4 are:
With the SRX5K-SCB4 Switch Control Board, Increased Fabric Bandwidth mode is the default mode on
the SRX5600 and SRX5800 Services Gateways and services gateways will use six active planes without
any spare planes.
With the Redundant Fabric mode, the SRX5600 and SRX5800 Services Gateways will use four active
planes and will have two spare planes.
Full performance with fabric redundancy for higher-capacity line cards.
Two 10-Gigabit Ethernet SFP+ ports (These ports are disabled and reserved for future use).
Increased Fabric Bandwidth mode is the default fabric mode of SCB4. In this mode you must install two
SCB4s in SRX5600 and three SCB4s in SRX5800 Services Gateways.
You can change the fabric mode of SCB4 from Increased Fabric Bandwidth mode to Redundant Fabric
mode using the CLI. If you change the fabric mode of SCB4 to Redundant Fabric mode you must install
two SCB4s in SRX5600 and you can install either two or three SCB4s in SRX5800 Services Gateways.
If you are upgrading from SCB3 (Redundant Fabric mode is the default fabric mode in SCB2 and SCB3) to
SCB4 and installing only two SCB4s, you must have Junos OS 19.3R1 or later and change the default fabric
mode of SCB4s to Redundant Fabric mode by using the CLI.
NOTE: To achieve maximum throughput on an SRX5800 Services Gateway, you must install
only two SCB4s (configured in redundant fabric mode) in a fully loaded chassis (for example: 3x
IOC4 + 7x SPC3 + 2x RE3 + 2x SCB4). If you install three SCB4s into the fully loaded chassis
(for example: 3x IOC4 + 7x SPC3 + 2x RE3 + 3x SCB4) the chassis will hit chassis power limit
and one of the line cards will go offline due to power shortage.
You can change the fabric mode by following one of these two methods:
1. Use the CLI command request chassis fabric mode <increased-bandwidth|redundant-fabric>
2. Save the change in the Configuration file
set chassis fabric redundancy-mode increased-bandwidth
set chassis fabric redundancy-mode redundant
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