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Author Topic: rate limiting ers8600  (Read 2992 times)

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Offline dekdek

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rate limiting ers8600
« on: October 20, 2013, 01:07:31 AM »
hi everyone,

i was wondering if the limitation applies to inbound broadcast or outbound broadcast or the both of two ??


Offline TankII

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Re: rate limiting ers8600
« Reply #1 on: October 21, 2013, 04:58:47 PM »
Inbound only.
If you do all ports, then you get in and out covered.

:-)

TankII

Offline dekdek

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Re: rate limiting ers8600
« Reply #2 on: October 22, 2013, 09:13:55 AM »
thank tankll !
docs i've found (large campus best practices, this helpfull forum...) were not very perfectly clear about that.
Ok now, what i've done if it could help :

1/ rate-limit all ports on 8600 core switch.  R-RS modules so we must talk in kbps : broadcast/multicast : 600 kbps .
Large Campus Technical Solution guide :
ERS 8600 (R-series, RS-series modules)
Broadcast / multicast bandwidth limiting
Allowed rate is in kbps
Recommendation
3 times normal kbps

But what traffic they talk (just broadcast ???...)

2/ every 5mns nedi (http://www.nedi.ch/), a wonderfull open tool, scan the core switch with snmp (it takes only 10s) and write it all in mysql tables. New version include a field in interfaces table : dinbrc which is inbroadcast interface difference between 2 scan. So a little sql request piped with a mail tell me when too many broadcast are coming from an interface.

3/
i've tested with a tool called packeth to simulate a storm :
  * inbound bcast from interface test (interface 8/43) --> 600 000 bcast/s
  * all the others interfaces --> outbound bcast never exceed 900 bcast/s
  * 3mns later i received an email tell me interface 8/43 is involved with a broadcast storm.
   
« Last Edit: October 22, 2013, 09:34:15 AM by dekdek »

Offline TankII

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Re: rate limiting ers8600
« Reply #3 on: October 22, 2013, 10:57:19 AM »
It should also show up in the syslog.  We used to use this method on ES470's years ago in a GE Patient Monitoring system.  Anything over 60 broadcast frames/sec seen by any individual device would impact the GE central stations' ability to view bedside wave-forms.
We set the threshold to 1% (which is still higher than we wanted) and if the threshold was hit, a syslog went out.  What we did was script an action - if the threshold was hit, the script would shut the port down.
With the ERS series, being able to rate-limit by packets/sec makes a huge difference!  You can set the inbound limit to 40/sec and never have to worry.

TankII

Offline dekdek

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Re: rate limiting ers8600
« Reply #4 on: October 22, 2013, 11:25:04 AM »
i can't find any trace in the syslog --> show log file
no broadcast rate limit exceed !
maybe should i configure it ?

Offline TankII

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Re: rate limiting ers8600
« Reply #5 on: October 22, 2013, 09:45:14 PM »
What level is your syslog configured for?  You know... It might be an SNMP trap and not a syslog.

It's been a while since we did that pilot project, and I wasn't the lead Engineer either.

TankII