[j-nsp] SRX Active/Active

Brian Spade bitkraft at gmail.com
Sun Jun 26 14:40:40 EDT 2016

Hi Aaron,

On Sun, Jun 26, 2016 at 11:19 AM, Aaron Dewell <aaron.dewell at gmail.com>
> You are correct - RG0 will always be active/passive.  A full control
plane failover will always be painful.
> SRX active/active is more about the interfaces in use.  You can arrange
for half of your traffic to prefer FW1 vs. FW2 and achieve active/active in
that way so you’ll take less of a hit when an interface fails (or a
neighbor device goes down).  So that’s really what you are protecting
against, which seems like you’ve done that.

Thanks for your feedback.  It will be a lot of configuration, but was
thinking I could do the following to limit RG0 failure (or southbound Core

   - /31 transit VLAN per link (per VRF).  So the total number of /31
   transit's needed will be 4 * # of VRFs (28 /31's in my case).
   - Graceful restart configured on the SRX to limit RG0 failure.
   - Core1 failure (or Core2 failure) should be limited with graceful
   restart and all uplinks having an OSPF adjacencies.

Anyways, just wondering your thoughts on this.  I will probably just have
to lab it to see how it performs.

If active/active is not a good way, I might have to add in two MX border
routers... That seems like a waste since I just need a default route via


>> On Jun 26, 2016, at 12:15 PM, Brian Spade <bitkraft at gmail.com> wrote:
>> Hi,
>> I'm trying to figure out the best way to setup an SRX cluster as
>> active/active.  I have attached a diagram of the topology, but it's a
>> full mesh of links.  The ISP links are local interfaces and the
>> southbound interfaces to the core routers are reth's.  Core1 is HSRP
>> primary for all VLANs.  FW1 is primary for RG1 and FW2 is primary for
>> RG2.  The IGP is OSPF but have many VRFs that are connected to the FW
>> with transit VLANs to bind the sub-interface to virtual router & zone.
>> The issue I have is Core2 has no active OSPF neighbors in this setup.
>> Therefore, if Core1 fails, there will be a control outage as Core2
>> establishes OSPF adjacencies.
>> So I'm thinking it might be better to remove the reth's and use local
>> interfaces on the FW/CORE links.  This way I can have a full mesh of
>> OSPF adjacencies and no control plane loss when Core1 fails.
>> Does anyone have thoughts on this or recommend the best way to achieve
>> this active/active full mesh setup?  If there's good reason to not use
>> active/active, I'd welcome the feedback.
>> Thanks.
>> /bs
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