[j-nsp] Tower top switch/router recommendation..

[Doug Hanks]

There's also a feature in Junos called prefix-action, which enforces per-prefix policing.  However I don't believe it's available on the EX.

http://www.juniper.net/techpubs/software/junos/junos94/swconfig-policy/prefix-action.html

Doug

From: EXT - plunin at senetsy.ru
Sent: Wednesday, March 23, 2011 2:43 PM
To: Peter Kranz
Cc: Doug Hanks; juniper-nsp at puck.nether.net
Subject: Re: [j-nsp] Tower top switch/router recommendation..


       Seems like filters+policers allows you to specify bandwidth-limit
and burst-size..

I.e. if you had a pool of 10 mbps.. you could carve it into individual
customer chunks at their... But no way to allow the customer to burst above
that bandwidth-limit to some specified higher BW, only allowed to specify
burst in terms of burst-size..

I need a way to ensure a customer gets their CIR at all times, and if
adequate extra BW available, they can burst to a higher (but limited to a
specified MIR) bandwidth..


Peter, what you talk about looks like a policer/shaper per VLAN. If I didn't miss something, of course.

EX series won't help you since it only supports policers for incoming (not outgoing) traffic and only 8 queues (and consequently 8 different shaper instances) per physical port. Of course you can try to do policing on ingress, but you'll need to write and maintain a hell of filters to distinguish the customers. This means you need to know something other than a VLAN to demux them: e. g. their IPs, but this means you have to know it, customers can't use overlapping space, etc. Not flexible at all and too much of manual work.

So in order to do what you want, some sort of aggregation router is needed, which would support either policers or shapers per outgoing vlan. In case of <1Gbps... well, maybe the higher J-series or SRX650 in packet mode (or even together with the stateful stuff, why not).

Than you can configure something like this:
http://books.google.com/books?id=EGi0zUwhB4QC&lpg=PA256&ots=672B7l6d7V&dq=junos%20policer%20out-of-profile&hl=ru&pg=PA256#v=onepage&q&f=false

Nothing personal about the book name :)

Two policers, first is for higher bw (say, 10M), which drops exceeding traffic, than, if it didn't, the next one (say, 5M), which somehow lowers the packets' priority: sets the fw-class, which is than mapped to an appropriate low-priority queue, sets the loss-priority, marks them as out-of-profile (AFAIR only supported on J/SRX but it's actually more or less the same as mapping to a class, which is bound to a lower-priority que,) or something else.