Juniper QFX3500, Hardware Documentation

Page: 370 / 669

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).
•
On QFX3500 and QFX3600, all non-channelized QSFP+ and fixed SFP+ interfaces.
BEST PRACTICE: Use the 40-Gigabit QSFP+ interfaces for the VCPs.
The advantages of connecting multiple 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, increased fault tolerance and high availability (HA) because a Virtual Chassis can remain
active and network traffic can be redirected to other member switches when a single member switch fails,
and a flatter, simplified Layer 2 network topology that minimizes or eliminates the need for loop prevention
protocols such as Spanning Tree Protocol (STP).
You can increase VCP bandwidth between member switches by configuring multiple interfaces between
the same two switches into VCPs. When multiple VCPs are interconnecting the same two member switches,
a Link Aggregation Group (LAG) bundle is automatically formed when the VCPs are on interfaces supporting
identical speeds. For instance, if you have two 40-Gigabit QSFP+ interfaces configured as VCPs between
member switches, a LAG with two member links with 80 Gbps of total bandwidth is formed. 10-Gigabit
SFP+ and 40-Gigabit QSFP+ interfaces configured as VCPs cannot be members of the same LAG, however.
The Virtual Chassis feature is not applicable to QFX devices in a QFabric.
Virtual Chassis can be installed in a single rack, multiple racks, or in wire closets.
Valid Configurations
Valid configurations are:
•
All QFX5100 members–in a ring topology this is Virtual Chassis; in a spine and leaf topology this is a
Virtual Chassis Fabric (VCF). For a cabling example of spine and leaf, see “Connecting a QFX5100 Device
in a Virtual Chassis Fabric” on page 295 .
•
All QFX3600 members
•
All QFX3500 members
•
A mixture of QFX3600 and QFX3500 members
•
A mixture of QFX5100, QFX3600, and QFX3500 members–use the QFX5100 switches as primary and
backup whenever possible.
•
A mixture of QFX5100, QFX3600, QFX3500, and EX4300 members except EX4300-48MP and
EX4300-48MP-S switches. EX4300 switches as the primary or backup is not supported; use QFX5100
switches in these roles whenever possible.
346