Fwd: Question about EX - SRX redundancy

Thu Apr 2 14:12:54 UTC 2015

Hello everyone!

I have got two Juniper EX series switches (on virtual chassis) and two SRX
devices on native clustering.

I am trying to have a highly available redundancy between them with atleast
2Gbps capacity all the time but kind of failing. I followed Juniper's
official page here
<http://kb.juniper.net/InfoCenter/index?page=content&id=KB22474> as well as
this detailed forum link here
<http://forums.juniper.net/t5/SRX-Services-Gateway/Best-way-of-redundancy-between-SRX-and-EX/td-p/181365>
.

I wish to have a case where devices are connected criss cross and following
the documentation I get two ae bundles in EX side and one single reth
bundle on SRX side. Both ae bundles on EX side have identical configuration
and VLAN has both ae interfaces called up.

If I do not go for criss cross connectivity like this:

EX0  (ae1) >> Two Patches to SRX0 (reth1)
EX1   (ae2)  >> Two Patches to SRX1 (reth1)

Then it works all well and redundancy works fine. In this case as long as 1
out of 4 patch is connected connectivity stays live but this has trade off
that if one EX goes down then I cannot make use of other corresponding SRX.

If I do criss connectivity, something like:

EX0 (ae1) >> Two Patches to SRX0 (reth1)
EX0 (ae1) >> One patch to SRX1 (reth1)

EX1 (ae2)  >> Two Patches to SRX1 (reth1)
EX1 (ae2)  >> One patch to SRX0 (reth1)

In this config system behaves very oddly with one ae pair (and it's
corresponding physical ports) working well while failover to other ae
bundle fails completely.

I was wondering if someone can point me out here.

Appreciate your time and help!

-- 

Anurag Bhatia
anuragbhatia.com

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