Re: Question about EX - SRX redundancy

[Anurag Bhatia <me () anuragbhatia com>]

Hello everyone


Just thought to update over here that I was able to get it done as needed.
Some quick points across the same on building redundancy between Juniper EX
and SRX devices:


   1. Virtual chassis in EX is very different from clustering in SRX and I
   did not realized the same initially.
   2. Key difference is that in virtual chassis both devices run in stacked
   config and act as single device while routing engine of primary/master EX
   is used.
   3. In case of SRX only one device runs at a time and ports of other SRX
   (slave) do not access traffic at all as long as it see the master is up via
   heartbeat.



So keeping above points in mind, I did 6 cables connection between EX and
SRX. On SRX side all 6 ports belong to same reth bundle (3 on SRX-0 and 3
on SRX-1). On Ex side configuration is in a way to use two ae bundles. If
we use same ae bundle for all 6 ports then problem comes up as a % of
traffic will hit SRX-1 (slave/secondary) and would be trashed which is not
desired. Hence we need to make two ae bundles as say ae1 and ae2. One
bundle goes towards one SRX (say master SRX-0) and other bundle goes
towards other SRX-1. Ports in ae1 and ae2 can be distributed across
multiple Ex to ensure redundancy.





So setup can work as:


EX-0 >> 2 patches >> SRX-0
EX-1 >> 2 patches >> SRX-1

Ex-0 >> 1 patch >> SRX-1
Ex-1 >> 1 patch >> SRX-0


Now all ports on Ex towards SRX0 go in ae1 and SRX1 go in ae2.



Thanks everyone for help and inputs. Have a good weekend ahead!



On Fri, Apr 3, 2015 at 3:52 AM, Hugo Slabbert <hugo () slabnet com> wrote:

> I just want to confirm your setup.
>
> The "criss-cross" setup you were describing is different from what I
> described.
>
> You listed:
>
>  > 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)
> ...meaning that your AEs cannot survive losing either one of the EX VC
> members, and you're splitting each AE's connectivity across the two SRX
> chassis cluster members.  You need to dedicate an AE to an SRX chassis
> cluster member.
>
> IOW: ae18 should have one LAG member on EX0 and one member on EX1, and
> both of those physical ports go to SRX0.  Likewise, ae20 should have one
> LAG member on EX0 and one member on EX1, and both of those physical ports
> go to SRX1.
>
> When you shut one of the AEs (e.g. ae18) in the setup I describe, you
> *will* lose connectivity to its corresponding SRX, as those are
> fate-sharing.  You would need to configure interface monitoring on the
> chassis cluster to flip over the primary to 2nd SRX in order to survive
> that, since the second AE (ae20) that is tied to the 2nd SRX is still up.
>
> Your failure modes are:
>
> e.g. 1: lose an EX, you lose the throughput that's being contributed to
> the AE by that VC member's ports, but both SRXs remain available and the
> primary shouldn't flip (provided your node priorities and
> interface-monitoring weights are set accordingly).
>
> e.g. 2: shut an AE (which spans both EX VC members), one SRX goes dark
> since you've killed the AE that's dedicated to it, and the primary will
> need to flip (either through interface monitoring or manually) in order for
> the setup to remain online.
>
> --
> Hugo
>
>
> On Fri 2015-Apr-03 02:41:35 +0530, Anurag Bhatia <me () anuragbhatia com>
> wrote:
>
>  Hi
> > Tried exactly same. Note: it's ae18 and ae20 on EX side and reth4 on SRX
> > side.
> >
> >
> > Initially worked but when I took down ae18, i.e ae18 is disabled, now on
> > ae20 I am getting:
> >
> > show interfaces ae20
> > Physical interface: ae20, Enabled, Physical link is Up
> >  Interface index: 533, SNMP ifIndex: 924
> >  Link-level type: Ethernet, MTU: 1514, Speed: 2Gbps, BPDU Error: None,
> > MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled,
> >  Flow control: Disabled, Minimum links needed: 1, Minimum bandwidth
> > needed: 0
> >
> >
> >
> > on reth4 on SRX I am getting:
> >
> > show interfaces reth4
> > Physical interface: reth4, Enabled, Physical link is Down
> >  Interface index: 132, SNMP ifIndex: 696
> >
> >
> >
> > Any idea why so? All physical ports are up (none is shut) and only thing
> > which I shut is one of ae bundles. Also rather then disabling ae18 if I
> > disabled associated physical ports behavior is just the same i.e reth4
> > goes
> > down.
> >
> >
> >
> >
> > Thanks for your time and help!
> >
> >
> >
> > On Fri, Apr 3, 2015 at 12:25 AM, Hugo Slabbert <hugo () slabnet com> wrote:
> >
> >  Putting the EXs in a VC and splitting your AEs across the 2x VC members
> > > takes care of that.
> > >
> > > EXVC  (ae1)  >> Two Patches to SRX0 (reth1)
> > > EXVC  (ae2)  >> Two Patches to SRX1 (reth1)
> > >
> > > ...where EXVC is a VC composed of EX0 and EX1, and ae1 and ae2 both have
> > > one member interface from each VC member.
> > >
> > > In a failure of EX0 or EX1, your throughput on ae1 and ae2 halves as they
> > > each lose a LAG member, but both SRX0 and SRX1 are still reachable.
> > >
> > > --
> > > Hugo
> > >
> > >
> > > On Thu 2015-Apr-02 23:50:46 +0530, Anurag Bhatia <me () anuragbhatia com>
> > > wrote:
> > >
> > >  Hi
> > >
> > > > Yes,
> > > >
> > > >
> > > > Since SRX0 connected to EX0 and SRX1 connected to EX1 (only). Thus
> > > > either
> > > > pair - 0 will work or pair - 1 will work. I wish if criss crossing
> > > > worked
> > > > then failure of one EX would have still made both SRX available.
> > > >
> > > >
> > > > In current worst case scenario - failure of EX0 and SRX1 can cause full
> > > > outage.
> > > >
> > > >
> > > >
> > > > Thanks.
> > > >
> > > > On Thu, Apr 2, 2015 at 9:21 PM, Hugo Slabbert <hugo () slabnet com> wrote:
> > > >
> > > >  In:
> > > >
> > > > >  > EX0  (ae1) >> Two Patches to SRX0 (reth1)
> > > > >
> > > > >  > EX1   (ae2)  >> Two Patches to SRX1 (reth1)
> > > > > > >   with:
> > > > >
> > > > >  > that if one EX goes down then I cannot make use of other
> > > > > corresponding
> > > > >
> > > > >  SRX.
> > > > > > >   Do you mean that e.g. if SRX0 is the chassis cluster primary and
> > > > > > EX0
> > > > > goes
> > > > > down, then you can't use SRX0, but you would like to be able to survive
> > > > > EX0
> > > > > going down *without* failing over the SRX chassis cluster to SRX1?
> > > > >
> > > > > --
> > > > > Hugo
> > > > >
> > > > >
> > > > > On Thu 2015-Apr-02 20:47:03 +0530, Anurag Bhatia <me () anuragbhatia com>
> > > > > wrote:
> > > > >
> > > > >  Hi
> > > > >
> > > > >
> > > > > > I thought cross chassis lag is supposed by the use of reth bundled at
> > > > > > SRX
> > > > > > end. I read this is basically the major difference in reth Vs ae
> > > > > > bundle
> > > > > > in
> > > > > > SRX.
> > > > > >
> > > > > >
> > > > > > Interesting factor here is that ae bundles can spread across multiple
> > > > > > EX
> > > > > > chassis in a virtual chassis environment but this cannot be the case
> > > > > > with
> > > > > > ae bundles in SRX.
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > Thanks.
> > > > > >
> > > > > > On Thu, Apr 2, 2015 at 7:59 PM, Bill Blackford <bblackford () gmail com>
> > > > > > wrote:
> > > > > >
> > > > > >  It's my understanding that a cross chassis LAG is not supported. If
> > > > > > there
> > > > > >
> > > > > >  is a way, I'm not aware of it. I'm running the same set up as your
> > > > > > > working
> > > > > > > example in my locations and for now, this suits my requirements.
> > > > > > >
> > > > > > > Sent from my iPhone
> > > > > > >
> > > > > > > > On Apr 2, 2015, at 07:12, Anurag Bhatia <me () anuragbhatia com>
> > > > > > > wrote:
> > > > > > > > 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
> > > > > > > >
> > > > > > > > Linkedin <http://in.linkedin.com/in/anuragbhatia21> | Twitter
> > > > > > > > <https://twitter.com/anurag_bhatia>
> > > > > > > > Skype: anuragbhatia.com
> > > > > > > >
> > > > > > > > PGP Key Fingerprint: 3115 677D 2E94 B696 651B 870C C06D D524 245E
> > > > > > > 58E2
> > > > > > --
> > > > > >
> > > > > >
> > > > > > Anurag Bhatia
> > > > > > anuragbhatia.com
> > > > > >
> > > > > > Linkedin <http://in.linkedin.com/in/anuragbhatia21> | Twitter
> > > > > > <https://twitter.com/anurag_bhatia>
> > > > > > Skype: anuragbhatia.com
> > > > > >
> > > > > > PGP Key Fingerprint: 3115 677D 2E94 B696 651B 870C C06D D524 245E 58E2
> > > > --
> > > >
> > > >
> > > > Anurag Bhatia
> > > > anuragbhatia.com
> > > >
> > > > Linkedin <http://in.linkedin.com/in/anuragbhatia21> | Twitter
> > > > <https://twitter.com/anurag_bhatia>
> > > > Skype: anuragbhatia.com
> > > >
> > > > PGP Key Fingerprint: 3115 677D 2E94 B696 651B 870C C06D D524 245E 58E2
> >
> > --
> >
> >
> > Anurag Bhatia
> > anuragbhatia.com
> >
> > Linkedin <http://in.linkedin.com/in/anuragbhatia21> | Twitter
> > <https://twitter.com/anurag_bhatia>
> > Skype: anuragbhatia.com
> >
> > PGP Key Fingerprint: 3115 677D 2E94 B696 651B 870C C06D D524 245E 58E2


-- 


Anurag Bhatia
anuragbhatia.com

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