Juniper QFX3500, Hardware Documentation

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RELATED DOCUMENTATION
Site Preparation Checklist for a QFX5100 Device | 92
Site Preparation Checklist for a QFX3500 Device | 95
Site Preparation Checklist for a QFX3600 or QFX3600-I Device | 93
Site Preparation Checklist for EX4300 Switches | 97
Connecting EX Series Switches in a QFX5100 Virtual Chassis Fabric
A Juniper Networks QFX5100 Virtual Chassis Fabric (VCF) is constructed using a spine-and-leaf architecture
and topology. In the spine-and-leaf architecture, each spine device is interconnected to each leaf device.
A VCF supports up to 20 total devices, and up to 4 devices can be configured into spine devices. EX4300
switches except EX4300-48MP and EX4300-48MP-S are supported in the leaf role in a QFX5100 VCF.
To understand the different hardware configurations supported, see “Virtual Chassis Fabric Hardware
Overview” on page 8 .
Although best practice is to use all QFX5100 switches in the VCF, you can also use EX4300 switches
except EX4300-48MP and EX4300-48MP-S as leaf devices.
Installations with combinations of QFX5100-48T, QFX3600, QFX3500, and EX4300 switches except
EX4300-48MP and EX4300-48MP-S as leaf devices in the QFX5100 VCF are called mixed mode. All VCF
installations can support 20 total devices, of which four QFX5100 devices can be configured into spine
devices.
You can install a VCF in a single rack, multiple racks, or in wire closets. You construct a VCF by configuring
and then cabling QSFP+ interfaces into Virtual Chassis ports (VCPs).
On EX4300 switches, QSFP+ ports 0 and 1 are configured as VCP by default. Non-channelized QSFP+
interfaces on EX4300 switches except EX4300-48MP and EX4300-48MP-S can be configured into VCPs.
You can also use the SFP+ uplink module ports as VCPs by configuring these ports as VCPs. The SFP+
network ports cannot be configured into VCPs. In EX4300-48MP and EX4300-48MP-S switches, you can
use only the built-in QSFP+ ports as VCPs. You cannot configure the ports on the uplink module in
EX4300-48MP and EX4300-48MP-S switches to Virtual Chassis ports (VCPs).
BEST PRACTICE: Use 40-Gigabit QSFP+ ports as VCPs when available.
Figure 135 on page 392 shows two QFX5100-24Q spine devices connected to a QFX5100-48S, QFX3600,
QFX3500, EX4300, and QFX5100-96S leaf devices using all QSFP+ ports as VCPs.
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