[j-nsp] Burst Reset question on Juniper M5

[michael.firth at bt.com]

I've seen it explained as a 'leaky bucket' model -  the bandwidth limit effectively becomes how fast data is allowed out of the bucket, and the burst-size-limit becomes the bucket size.
 
I'm not sure if this is an accurate representation of how it is really modelled, then, if it is, you would have to wait 10 seconds between each 10Mbit burst on your 1Mbit/s limited link. If you burst at the high rate for too long, the bucket becomes full and packets start being discarded.
 
Hope this helps
 
Michael

________________________________

From: juniper-nsp-bounces at puck.nether.net on behalf of Dave D
Sent: Wed 14/05/2008 18:41
To: juniper-nsp at puck.nether.net
Subject: [j-nsp] Burst Reset question on Juniper M5



Hello all,



  So a customer of mine has been asking me about burst-size-limit on Juniper
routers. Before I begin, I have a Juniper M5 running 7.6R4.3. My customer
has the burst size limit set on his port, but he is asking me some questions
I can't find the answers to.



This was a page from Juniper's site explaining burst-size-limit's...



http://www.juniper.net/techpubs/software/junos/junos76/swconfig76-network-interfaces/html/interfaces-summary53.html

My customer is asking about the conditions for the RESET of the burst
counter...


" its simple enough that if you go from 1 to 10mbps on a 1mbps
limited connection, and are allowed 1 Gig of traffic, it starts counting
at 10mbps, and when it hits 1 gig, it shapes to 1Mbps. That's easy.

But what if you burst to 10Mbps for 200 megs, then drop to 1Mbps for
10 seconds, then burst to 10Mbps for another 300 megs, drop to 1mbps,
burst again, etc - you could end up with an aggregate equivalent bandwidth
rate of 9Mbps for eg even tho your shaping is at 1mbps.

I'd expect there's some counter or multiplier or something that
determines how long you have to *NOT* burst for before the counter is
cleared (or some decay rate or something, perhaps every non burst
byte sent comes off the burst counter, that'd be one way.





I would think Juniper would be smart enough to have some sort of built in
reset but I am no certain. Does anyone know offhand?





Any and all explanations would be greatly appreciated,



Thank you very much everyone.

Dave
_______________________________________________
juniper-nsp mailing list juniper-nsp at puck.nether.net
https://puck.nether.net/mailman/listinfo/juniper-nsp