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56 Cards in this Set

  • Front
  • Back
Junos OS functionality is compartmentalized into?
1. Multiple processes known as Daemons.

2. Each process runs in its own protected memory space

3. ensuring that one process cannot
directly interfere with another
How are core features in JunOS able to work in a consistent manor across all platforms?
Single software source base code
why can Junos OS can support many different platforms from a common code base?
The separation of the control and forwarding planes
What is the RE Routing Engine responsible for?
Protocol updates and system management
The RE maintains the?
Routing tables, bridging table, and primary forwarding table and connects to the Packet Forwarding Engine (PFE)
through an internal link.
What is responsible for
forwarding transit traffic through the device?
1. PFE Packet forwarding Engine.

2. PFE uses
application-specific integrated circuits (ASICs) for increased performance
How does the PFE receives the forwarding table (FT) from the RE?
Via an Internal link
high availability features?
1. graceful Routing Engine switchover
2. nonstop active routing (NSR), and unified
3. in-service software upgrades (ISSUs).
What is the central processing component of the forwarding plane?
PFE - Packet forwarding Engine
In the PFE, Why does keeping a local copy of the forwarding table make it more efficient?
1. Eliminates the need to consult the RE-Routing Engine each time a packet needs to be forwarded.
What services does the PFE implement?
1. policers that provide rate limiting,
2. stateless firewall filters,
3.class of service (CoS). Other services are available through special interface cards that you can add to the PFE
What is Transit Traffic?
Transit traffic consists of all traffic that enters an ingress network port, is compared against the forwarding table
entries, and is finally forwarded out an egress network port toward its destination.
What does the forwarding Plane do with Transit Traffic?
only forwards never sends to the control plane for processing.
To successfully forward transit traffic to its destination, what must exist in the forwarding table?
An entry for the destination
Exception traffic?
1. Does not pass through the local device but requires some special handling (Protocol updates, telnet, ICMP traffic)
How is Exception traffic destined for the RE forwarded?
1.Via the internal link.
2 exception traffic traversing the internal link to the RE is Rate limited to protect the RE from DoS Denial of Service attacks (rate limiter is not configurable)
T Series core routers?
The T Series core routers provide up to 25.6 Tbps of throughput. The T Series family is ideal for service provider
environments and is deployed within the core of those networks.
J Series Services Routers?
The J Series services routers provide up to 2 Gbps of throughput. The J Series services routers are deployed at
branch and remote locations in the network to provide all-in-one secure WAN connectivity, IP telephony, and
connection to local PCs and servers through integrated Ethernet switching.
MX Series Ethernet Services Routers?
The MX Series Ethernet services routers provide up to 960 Gbps of aggregate half-duplex throughput. The MX Series
family is targeted for dense dedicated access aggregation and provider edge services in medium and large point of
presence (POPs). Large enterprise environments and service providers can leverage MX Series Ethernet services
routers for a variety of network functions including Ethernet transport and aggregation, and can use them to offer
new Ethernet-based services.
EX Series Ethernet Switches?
The EX Series Ethernet switches provide up to 6.2 Tbps of full duplex throughput. The EX Series switches are
designed for access, aggregation, and core deployments and are well suited for low-density to high-density
enterprise and data center environments.
SRX Series Services Gateways?
The SRX Series services gateways provide up to 120 Gbps of full duplex throughput. The SRX Series family is
designed to meet the network and security requirements for consolidated data centers, managed services
deployments, and aggregation of security services in both enterprise and service provider environments.
What are some advantages of Junos OS?
The Junos OS is compartmentalized into multiple software processes. Each process runs in its own protected memory space,
ensuring that one process cannot directly interfere with another. This modularity also ensures that new features can be added
with less likelihood of breaking current functionality.
What are the primary functions of the control plane and the forwarding plane on Junos devices?
The primary functions of the control plane are to maintain routing intelligence, control and monitor the chassis, and manage
the Packet Forwarding Engine (PFE). The primary functions of the forwarding plane are to forward packets and to implement
advanced services.
How are transit and exception traffic processed?
Transit traffic is forwarded through the PFE on platforms running the Junos OS, based on the forwarding table installed on
the PFE. Exception traffic is processed locally by the platform running the Junos OS by either the PFE or the RE depending
on the type of traffic. Host-bound packets, such as protocol and management traffic, are passed directly to the RE for
processing, while traffic requiring ICMP error message responses is typically handled by the PFE.
What Platforms run Junos OS?
Platform families that run the Junos OS include M Series, T Series, J Series, MX Series, EX Series, and SRX Series.
CLI Operation mode?
In operational mode, you use the CLI to monitor and troubleshoot the device. The monitor, ping, show, test,
and traceroute commands let you display information and test network connectivity for the device.
Configuration Mode?
In configuration mode, you can configure all properties of the Junos OS, including interfaces, protocols, and user
access, as well as several system hardware properties.
Batch Configuration Changes?
This design feature allows you to group together and apply multiple configuration changes to the running
configuration as a single unit.
Active Configuration?
The active configuration is the configuration currently operational on the system and is the configuration the system
loads during the boot sequence. This concept is analogous to both the running configuration and startup
configuration in software from other vendors
Candidate Configuration?
The candidate configuration is a temporary configuration that might possibly become the active configuration. When
you configure a device running the Junos OS, the software creates a candidate configuration and initially populates it
with the active configuration running on that device. You then modify the candidate configuration. Once satisfied
with your modifications, you can commit the changes. This action causes the candidate configuration to become the
active configuration.
configure command?
The configure command causes a candidate configuration to be created and populated with the contents of the
active configuration. You can then modify the candidate configuration with your changes.
For a candidate config to take affect in the active config you must?
commit the changes
rollback n command?
The Junos OS maintains a
configuration history by storing previously active configurations. The software saves a maximum of 50
configurations. This number includes the current active configuration, which is also known as rollback 0, and up
to 49 previously active configurations. If you perform a rollback operation, keep in mind that the related
configuration does not become active until you issue a commit. When you issue a commit and 50 rollback
configurations exist, the software purges the last rollback configuration—rollback 49.
how do you enter configuration mode?
prompt changes to
what is configure exclusive?
excludes other users from editing the configuration.
deactivate command?
deactivates particular portion of a configuration ie BGP
insert command?
inserts configuration to a specified location...(like a sequence number)
annotate command?
adds notes/comments to configuration
show command?
in configuration mode. will show the candidate show command.
commit check?
validates syntax
commit confirmed?
applies previous rollback is a second commit isnt applied within 10mins
commit at (time)?
Schedules a commit at a specified time
commit comment?
adds a log entry
commit and-quit?
saves time by exiting configuration mode after commit.
show | compare
compares actual changes in candidate and active configuration.
Which modes of exist in Junos OS?
Two primary modes exist within the Junos OS: the operational mode and the configuration mode. A third mode also exists in
the form of the FreeBSD shell.
Which operations are performed at each mode?
You use the operational mode to monitor and troubleshoot the software, network connectivity, and hardware. You use the
configuration mode to configure a device running the Junos OS, including interfaces, protocols, user access, and system
Which keystrokes complete a system command and a user-defined variable?
You use the Spacebar to complete a command and the Tab key to complete a variable.
Which command provides the quickest method to return to the top of the hierarchy?
The top command is the quickest method of returning to the top of the hierarchy.
what is the difference between active and candidate configuration?
The active configuration has been committed and is in use, whereas the candidate configuration is not active until you perform
a commit operation.
which command displays the differences between active and candidate configuration?
The show | compare command displays the differences between the current active and candidate configurations
How do you Gracefully Shut Down the Junos OS?
1. request system halt
2. on devices with redundant RErequest system halt both-routing-engines
3.For EX Series switches participating in a virtual
chassisrequest system halt all-members
Initial Configuration Checklist

In addition to root authentication, we also recommend that you configure the following items?
1. Hostname
2. system time
3.System services for remote access (Telnet, SSH); and
4.Management interface and static route for management traffic.
Factory-default host name?
When you login as Root user you are in?
Unix Shell and need to type cli to go into command line interface, must use exit to leave cli
What is FPC?
Flexible PIC Concentrator