nanog mailing list archives

Re: Question about EX - SRX redundancy


From: Anurag Bhatia <me () anuragbhatia com>
Date: Fri, 3 Apr 2015 02:41:35 +0530

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


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