CHAPTER 1
Architecture Overview
•
Understanding Disaggregated Junos OS on page 3
•
Disaggregated Junos OS VMs on page 6
•
Understanding Virtio Usage on page 8
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Understanding SR-IOV Usage on page 10
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Comparing Virtio and SR-IOV on page 11
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Understanding Physical and Virtual Components on page 12
Understanding Disaggregated Junos OS
Many network equipment vendors have traditionally bound their software to purpose-built
hardware and sold customers the bundled and packaged software–hardware
combination. However, with the disaggregated Junos OS architecture, Juniper Network
devices are now aligned with networks that are cloud-oriented, open, and rely on more
flexible implementation scenarios.
The basic principle of the disaggregated Junos OS architecture is decomposition
(disaggregation) of the tightly bound Junos OS software and proprietary hardware into
virtualized components that can potentially run not only on Juniper Networks hardware,
but also, on white boxes or bare-metal servers. In this new architecture, the Juniper Device
Manager (JDM) is a virtualized root container that manages software components.
The JDM is the only root container in the disaggregated Junos OS architecture (there are
other industry models that allow more than one root container, but the disaggregated
Junos OS architecture is not one of them). The disaggregated Junos OS is a single-root
model. One of the major functions of JDM is to prevent modifications and activities on
the platform from impacting the underlying host OS (usually Linux). As the root entity,
the JDM is well-suited for that task. The other major function of JDM is to make the
hardware of the device look as much like a traditional Junos OS–based physical system
as possible. This also requires some form of root capabilities.
Figure 1 on page 4 illustrates the important position JDM occupies in the overall
architecture.
3Copyright © 2017, Juniper Networks, Inc.
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