Juniper EX4200T- Management Observations

So I’ve had been spending some time playing around with a juniper EX4200T from a management standpoint.

This post is just a place to put some observations and questions. Hopefully, some Junos Peeps will be able to shed a little light on some of these questions.

First, as both a criticism and a defence; Juniper does not use SNMP as their primary interface. I get that SNMP has it’s problems, but it’s what we have and if you want to bring Juniper into a network where there is already a network management system in place, I would think that they should at least do the minimum to improve their SNMP support to at least meet the bar.

I have to say; as an operationally focused network engineer, it does disturb me that I can’t even set the sys location from a simple SNMP set command.   

ifIndex

One of the first things I noticed about the Juniper box is that the seem to have some strangeness, at least compared to other vendors, around the number of interfaces. Specifically, I’ve got a 48 port switch with more than twice that many interfaces.  Upon a closer look, it seems that the Juniper switches, or at the very least the EX 4200t, seems to have two index values for every physical port.

Juniper SNMP Interfaces

 

One of the interesting questions that come up here is ” What ifIndex value do I poll?”.  I’d like to get interface stats on this device, but do I poll the ethernet port, or the prop virtual port?  And if both return the same values; Why would I chose one over the other?  

Anyone have a good explanation of WHY they went this direction? @steve did suggest to think of this like a sub interface in Cisco terms.  I’ve been trying to figure this out, but the most common reason I’ve used a sub-interface has been to create dot1q routing on a stick configurations.  I don’t see how that applies here?

 

MIB Walking 

Another strange thing is that it seems that the EX4200 cannot return all the interfaces when reading the ifTable by SNMP.  It may be that this is an issue with my MIB browser, but it’s definitely a pain in the butt.  

Junos-peeps: Anyone have a MIB browser that works here? Suggestions on code? Possibly a bug?

 

VLAN 0

One of the other things I noticed is that the default VLAN of the EX4200 is 0. Huh? VLAN 0? All of the interfaces on the switch belong to VLAN 0 initially.  I did find this article  from the Juniper website says that ” Some attached devices may not accept 802.1q-tagged frames, and therefore can reside only in VLAN 0.” 

Coming from a Cisco and HP background, I’ve always seen the native VLAN initially on a interface listed as VLAN 1.    Anyone able to explain this to me?

VLAN-Range: Anyone able to explain this to me? Now I checked the Juniper documentation .  But I wasn’t able to find an article which explained what exactly the function is for. 

 

If anyone has comments, I’d love to learn here. I freely admit I haven’t had time to get far enough into this to understand the benefits and I do bring the baggage of history to my perspective on this.  If someone has made the jump to Junos, I’d love to hear from you! 

 

@netmanchris