[j-nsp] small multitenant datacenter

[Ryan Goldberg]

Thanks Jeff-

> > Do you see an issue with blowing up ex4200s with all this ospf and vrrp?  I'm
> labbing tomorrow and will try to get the boxes to thrash.
> 
> I'm interested to know your thoughts on RE performance after you have
> labbed this scenario.  I've read the EX4200 supports 256 VRF-Lite instances,
> but like you, I imagine the control-plane may become sluggish before it gets
> to that point.

I also saw the vrf limits in the docs 

http://www.juniper.net/techpubs/en_US/junos11.1/topics/concept/bridging-vrf-ex-series.html

but if you look at 11.2

http://www.juniper.net/techpubs/en_US/junos11.2/topics/concept/bridging-vrf-ex-series.html

poof, limits gone?

I'm working remote right now and just have one MX80 plumbed to one 4200.  I brought up 300 virtual-routers with ospf between them.  During the commit on the 4200s that initially fired the ospfs load went to about 6.5 and then fell off quickly.  From load of .05 to 6.5 and back to .05 was under 2 minutes (roughly).

Each of the 300 vrfs has just the connected routes between the boxes and then another route on the other side of the MX80.  So I loaded 12k static routes onto the MX80 into one of the vrfs and there was almost no noticeable impact on the 4200, cpu climbed to like 50% for maybe 20 seconds.  I then dropped the link briefly between the boxes and the impact to the 4200 was about the same, 50% or so for maybe 20-30 seconds.

I'll have more time to play tomorrow, and will report back findings.
 
> I noticed you include the EX3300 in your design.  I also considered this switch
> and decided against it once I read the feature table.  I would like to use them
> once additional features are working, but right now, it lacks critical items like
> storm-control.
> https://www.juniper.net/techpubs/en_US/release-
> independent/junos/topics/concept/ex-series-software-features-
> overview.html

I will re-review what we may need/what may be lacking.  It seems the 3300s are catching up, and we have had good luck in small single-tenant deployments (3 vmware host + SAN), using them strictly as stacked L2 switches, generally in place of a pair of 3750x or 2960s.

> Also, you mention both EX4200 virtual-chassis, and VRRP.  I think it is unusual
> to choose BOTH V-C and STP+VRRP as redundancy mechanisms, because you
...
> I think you should pick one: V-C or STP+VRRP, depending on which

This has been causing me loss of sleep.  On the one hand, I like "independent brains" and feel that hinging everything on IRF, VC, VSS, etc, just puts you in a riskier spot, with invisible magic keeping things afloat....

> My experience with EX4200 virtual-chassis has been extremely good since
> Junos 10.4.  Before then, we had problems with file system corruption on the
> EX4200, but this was fixed in 10.4.  I have not had any serious stacking-specific
> bugs since about Junos 9.5.  I rely totally on EX4200 virtual-chassis for
> redundancy in many environments, and am very pleased with the results.

But like you, I've had really good luck with the 4200s.  In fact, I have had zero issues.  We didn't start getting them till 10.4, so I think we escaped some initial ick.  The invisible magic might be better than a relatively delicate and somewhat complex configuration.  

> Good luck with your project.  I hope my comments are constructive and
> helpful!

Very much so.  As I play with the failure modes, and try and balance performance and manageability with meeting the various business goals and constraints, I think it will be a bunch of fun.

Thanks-
Ryan