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MC-LAG ping issue

‎11-17-2018 10:01 AM

hello Junos

 

I have TOR SW connected to MC-LAG ex9208 connected as simple ae trunk interface, when i ping from TOR to ex9200-A the time ping dont look good for example the time=12ms, time= 9ms, time=4ms for each ping why is that.

and when i ping to ex9200-B i get interrupted by message between each ping like its get redirect or something.

 

anyone faced similar situation or knows how to fix it?

 

and thanks in advance

5 REPLIES 5
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Re: MC-LAG ping issue

‎04-05-2019 08:08 AM

Good day,

 

If you can provide configuration and results of the tests, we can try to make some conclusions.

In general, if you have High CPU on your box, you will see some delays in ping or other traffic which is proccessed by CPU.

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Re: MC-LAG ping issue

‎04-06-2019 05:55 AM

I would guess that the LAG configurations don't exactly match.  Perhaps one is expecting active passive links and the other active active would produce these results.

 

Steve Puluka BSEET - Juniper Ambassador
IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)
http://puluka.com/home
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Re: MC-LAG ping issue

‎09-27-2019 01:45 AM

Hey.
I have EX4600 AND the same problem. Ping between Juniper
time=11.157 ms
the same response time from a switch directly connected to one of the EX 4600 switches. As under ping through MC-LAG so and the usual link.

But the CPU usage is 7-10 percent on both EX4600.

15 min CPU utilization:
User               7 percent
Background  0 percent
Kernel           1 percent
Interrupt       0 percent
Idle                89 percent
Model EX4600-40F

and other

15 min CPU utilization:
User                7 percent
Background   0 percent
Kernel            1 percent
Interrupt        0 percent
Idle                 89 percent
Model EX4600-40F


JUNOS Base OS Software Suite [18.4R2.7]

??????? 
Why and how to fix it.
If need a configuration I will send.

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Re: MC-LAG ping issue

‎09-27-2019 10:47 AM

I believe this has been discussed on this Forum mutliple times before, but Ping times using Juniper products as either source or destination are NOT a good test, period!!

 

Reason being you are pinging to or from the RE, which is some form of a CPU, and ping is a very low priority item, and replies could get delayed due to other tasks or even original packet discarded.

 

The true test for delay (I assume this is what you are testing) is THROUGH the device, not to/from the device.  Through is via the fast hardware, to/from always involves the RE/CPU.

 

Now if the test is to confirm reachability between devices and to monitor for potential delay, then I would suggest using some functionality like RPM - https://www.juniper.net/documentation/en_US/junos/topics/example/security-basic-rpm-probe-configurin...

 

BTW, in the case of delay I have never seen the electrical signals across a wire go slower or faster -Smiley Happy  Delay is almost caused by some form of packet loss or packet handling priority.

 

Just FYI only.

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Re: MC-LAG ping issue

‎09-27-2019 12:09 PM

Thank you for eliminating illiteracy. )))