Juniper

QinQ and L2PT on Junos ELS

I recently had to test QinQ on EX4600 along with Layer 2 Protocol Tunneling for Spanning Tree Protocol. Q-in-Q tunneling and VLAN translation allow service providers to create a Layer 2 Ethernet connection between two customer sites. Q-in-Q tunneling is useful when customers have overlapping VLAN IDs because customersā€™ VLAN (C-VLAN) tags are prepended by… Keep reading »

Consistent Management IP address

I was asked recently by a less experienced colleague of mine if there is a way to configure a single IP address that you can always use to connect to the master Routing Engine of a device that supports dual Routing Engine. My colleague already knew about re0 and re1 configuration groups that allows you… Keep reading »

Junos-defaults group

Have you ever tried to to configure a user’s password that is shorter than 6 characters during the initial configuration and found out that you cannot do this? If you did, you should have seen this:   {master:0}[edit] root@qfx5100# set system login user test authentication plain-text-password New password: error: minimum password length is 6 {master:0}[edit]… Keep reading »

Sending Junos traceoptions to a syslog server

We discussed in this post how to enable remote tracing on Junos. The problem is that the feature can be enabled only for some specific processes. There is another way how to send any traceoptions to a syslog server. It’s not a Junos specific feature, but a combination of different Junos and Linux/Unix features. Let’s… Keep reading »

Remote tracing on Junos

It’s possible that for specific processes in Junos, the logs/traceoptions to be sent remotely. You can have there a syslog server where the logs will be stored for later analysis. The feature is activated for all processes that supports it and you can disable remote tracing specifically for each process. Keep in mind that once… Keep reading »

Conditional default route advertising

A default route is helping you to send packets to a device when you don’t have specific routing information about the destination of the packets hoping that the device will know how to route the packets to the destination. But it’s not always true. The device advertising the default route might not know how to… Keep reading »

Junos Recovery on QFX5100/EX4600

It’s possible that after a failed installation, the QFX5100 might not work properly and be left in a state that makes it inaccessible from remote and needs a new software installation by copying the software from the USB to the QFX5100 or by using the installation from USB. There is another way to recover the… Keep reading »

Per-packet load balancing in routing-instance

By default, whenever there are multiple next-hops available to a destination, Junos installs only one next-hop in the forwarding-table, although the routing-table will show both next-hops. The user has the possibility to install multiple next-hops in the forwarding-table for the active route. This is called per-packet load balancing. Keep in mind that the load balancing… Keep reading »

In-Service Software Upgrade(ISSU) on QFX5100

In order to upgrade a device, traditionally a downtime is needed to upgrade the Routing Engine. You could avoid the downtime if you have redundant Routing Engines. This is possible in the chassis based platforms where features that enable high availability likeĀ Graceful Routing Engine Switchover (GRES), NonStop Routing (NSR) and NonStop Bridging (NSB) allows smoother… Keep reading »

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