[LARTC] Using HTB as an ISP "provisioning engine"

[LARTC] Using HTB as an ISP "provisioning engine"

[Brian Capouch]

I am new to shaping but not to routing; forgive me if this request is 
inappropriate for this list.

I am a very small ISP and would like to use HTB to enforce contractual 
bandwidth limits on my customers.  I am trying to think through one 
aspect of this that is vexing me.  I'm sure it's no great secret that 
many ISPs oversell their bandwidth, and in our case we have a 
combination of accounts that total approximately 2.2Mbs on our feed, 
which is 1.2Mbs. (Concentrating right now on our download stream)

How could something like this be accomodated?  The documentation says 
that the total bandwidth allocations of a set of subclasses should total 
that assigned to the class.

But my understanding is that if I bump up the bandwidth on the primary 
class to a value greater than my actual bandwidth, then I'm going to be 
filling up queues at the upstream ISP and negatively affecting my 
performance.

I'm sure there is something I'm missing, but I've discussed this with a 
couple of fellow network engineers and neither was able to posit how 
such thing might work, although they both said they were sure that it is 
a common scenario.

Thanks.

B.

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Re: [LARTC] Using HTB as an ISP "provisioning engine"

[Stef Coene]

On Thursday 19 December 2002 21:51, Brian Capouch wrote:
> I am new to shaping but not to routing; forgive me if this request is
> inappropriate for this list.
>
> I am a very small ISP and would like to use HTB to enforce contractual
> bandwidth limits on my customers.  I am trying to think through one
> aspect of this that is vexing me.  I'm sure it's no great secret that
> many ISPs oversell their bandwidth, and in our case we have a
> combination of accounts that total approximately 2.2Mbs on our feed,
> which is 1.2Mbs. (Concentrating right now on our download stream)
>
> How could something like this be accomodated?  The documentation says
> that the total bandwidth allocations of a set of subclasses should total
> that assigned to the class.
>
> But my understanding is that if I bump up the bandwidth on the primary
> class to a value greater than my actual bandwidth, then I'm going to be
> filling up queues at the upstream ISP and negatively affecting my
> performance.
>
> I'm sure there is something I'm missing, but I've discussed this with a
> couple of fellow network engineers and neither was able to posit how
> such thing might work, although they both said they were sure that it is
> a common scenario.
You can create a root class with rate = ceil = 1.2 Mbps.  Create a class for 
each customer with ceil = selled bandwidth and the sum of the rates=1.2Mbps.

Example :
You selled 1.1 Mbps to customer1 and 0.37 (=2.2Mbps/6) to 3 other customers.  
So you have a total bandwidth of 2.2Mbps.  But you have only 1.2 Mbps 
available.
class rate = ceil = 1.2 Mbps
  class1 rate = 0.6, ceil = 1.1Mbps
  class2 rate = 0.2, ceil = 0.37Mbps
  class3 rate = 0.2, ceil = 0.37Mbps
  class4 rate = 0.2, ceil = 0.37Mbps

The bandwidth you selled to the customers is the ceil.  They never can use 
more then the ceil.  If one customer is using no bandwidth, the remaining 
bandwidth is given to the other customers.
If all customers are using all bandwidth, each customer is "punished" in the 
same way.

You can also give the customers a possibility to use as much bandwidth as 
available.  To do so, give each class ceil = 1.2Mbps, but that bandwidth is 
not guaranteed.  In this case, the rate is the minimum bandwidth they can 
get.  So for a SLA, you can say to the customer : "You have a minimum 
bandwidth of 0.6Mbps and a maximum bandwidth of 1.2Mbps."

Stef

-- 

stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
     #lartc @ irc.oftc.net

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RE: [LARTC] Using HTB as an ISP "provisioning engine"

[S Mohan]

You can go one step further. If you are charging differential rates to
customers, the you can fine tune as per scenario discussed under:

Let us say customer A has paid more for bandwidth than customer B, then
customer should have a greater lien on spare bandwidth than customer B. This
is achieved by prio in qdisc. Let us give customer A prio 1 and B prio 2. If
customer A and B have used their rattes and 400Kb spare bandwidth is
available, then the full 400kb goes to A. If customer A is at 800kb and B at
250Kb, then 300Kb (1.1 ceiling-0.8 actual) goes to A so that he hits ceiling
and the balance 100kb goes to B.

Stef is this scenario correct. In case I'm wrong, please let me know.

Mohan
-----Original Message-----
From: lartc-admin@mailman.ds9a.nl [mailto:lartc-admin@mailman.ds9a.nl]On
Behalf Of Stef Coene
Sent: 20 December 2002 02:40
To: Brian Capouch; lartc@mailman.ds9a.nl
Subject: Re: [LARTC] Using HTB as an ISP "provisioning engine"


On Thursday 19 December 2002 21:51, Brian Capouch wrote:
> I am new to shaping but not to routing; forgive me if this request is
> inappropriate for this list.
>
> I am a very small ISP and would like to use HTB to enforce contractual
> bandwidth limits on my customers.  I am trying to think through one
> aspect of this that is vexing me.  I'm sure it's no great secret that
> many ISPs oversell their bandwidth, and in our case we have a
> combination of accounts that total approximately 2.2Mbs on our feed,
> which is 1.2Mbs. (Concentrating right now on our download stream)
>
> How could something like this be accomodated?  The documentation says
> that the total bandwidth allocations of a set of subclasses should total
> that assigned to the class.
>
> But my understanding is that if I bump up the bandwidth on the primary
> class to a value greater than my actual bandwidth, then I'm going to be
> filling up queues at the upstream ISP and negatively affecting my
> performance.
>
> I'm sure there is something I'm missing, but I've discussed this with a
> couple of fellow network engineers and neither was able to posit how
> such thing might work, although they both said they were sure that it is
> a common scenario.
You can create a root class with rate = ceil = 1.2 Mbps.  Create a class for
each customer with ceil = selled bandwidth and the sum of the rates=1.2Mbps.

Example :
You selled 1.1 Mbps to customer1 and 0.37 (=2.2Mbps/6) to 3 other customers.
So you have a total bandwidth of 2.2Mbps.  But you have only 1.2 Mbps
available.
class rate = ceil = 1.2 Mbps
  class1 rate = 0.6, ceil = 1.1Mbps
  class2 rate = 0.2, ceil = 0.37Mbps
  class3 rate = 0.2, ceil = 0.37Mbps
  class4 rate = 0.2, ceil = 0.37Mbps

The bandwidth you selled to the customers is the ceil.  They never can use
more then the ceil.  If one customer is using no bandwidth, the remaining
bandwidth is given to the other customers.
If all customers are using all bandwidth, each customer is "punished" in the
same way.

You can also give the customers a possibility to use as much bandwidth as
available.  To do so, give each class ceil = 1.2Mbps, but that bandwidth is
not guaranteed.  In this case, the rate is the minimum bandwidth they can
get.  So for a SLA, you can say to the customer : "You have a minimum
bandwidth of 0.6Mbps and a maximum bandwidth of 1.2Mbps."

Stef

--

stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
     #lartc @ irc.oftc.net

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Re: [LARTC] Using HTB as an ISP "provisioning engine"

[Daniel Egger]

Am Don, 2002-12-19 um 22.10 schrieb Stef Coene:

> Example :
> You selled 1.1 Mbps to customer1 and 0.37 (=2.2Mbps/6) to 3 other customers.  
> So you have a total bandwidth of 2.2Mbps.  But you have only 1.2 Mbps 
> available.
> class rate = ceil = 1.2 Mbps
>   class1 rate = 0.6, ceil = 1.1Mbps
>   class2 rate = 0.2, ceil = 0.37Mbps
>   class3 rate = 0.2, ceil = 0.37Mbps
>   class4 rate = 0.2, ceil = 0.37Mbps

> The bandwidth you selled to the customers is the ceil.  They never can use 
> more then the ceil.  If one customer is using no bandwidth, the remaining 
> bandwidth is given to the other customers.
> If all customers are using all bandwidth, each customer is "punished" in the 
> same way.

Nice, however (see other mail) it seems unpossible to remove subclasses
on-the-fly which is a hard requirement here. Do I have to recreate the
whole tree on the fly? If so, won't this negatively affect the queues
because all statistics are lost?

-- 
Servus,
       Daniel


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Re: [LARTC] Using HTB as an ISP "provisioning engine"

[raptor]

|
|Example :
|You selled 1.1 Mbps to customer1 and 0.37 (=2.2Mbps/6) to 3 other customers.  
|So you have a total bandwidth of 2.2Mbps.  But you have only 1.2 Mbps 
|available.
|class rate = ceil = 1.2 Mbps
|  class1 rate = 0.6, ceil = 1.1Mbps
|  class2 rate = 0.2, ceil = 0.37Mbps
|  class3 rate = 0.2, ceil = 0.37Mbps
|  class4 rate = 0.2, ceil = 0.37Mbps
]- this is fasable only if u have predetermined number of clients, what if u have varing number of clients... any time u add or remove client u have to recalculate rate and ceil's...
Yes u can achieve this with a little bit of scripting i.e. preprocessing the config but this is not a good solution..
If there was available some simple arithmetic in the QoS it would be better :")

raptor
PS. I'm having similar scenario and still many variants goes trought my head... 
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Re: [LARTC] Using HTB as an ISP "provisioning engine"

[Stef Coene]

On Monday 23 December 2002 17:30, raptor wrote:
> |Example :
> |You selled 1.1 Mbps to customer1 and 0.37 (=2.2Mbps/6) to 3 other
> | customers. So you have a total bandwidth of 2.2Mbps.  But you have only
> | 1.2 Mbps available.
> |class rate = ceil = 1.2 Mbps
> |  class1 rate = 0.6, ceil = 1.1Mbps
> |  class2 rate = 0.2, ceil = 0.37Mbps
> |  class3 rate = 0.2, ceil = 0.37Mbps
> |  class4 rate = 0.2, ceil = 0.37Mbps
>
> ]- this is fasable only if u have predetermined number of clients, what if
> u have varing number of clients... any time u add or remove client u have
> to recalculate rate and ceil's... Yes u can achieve this with a little bit
> of scripting i.e. preprocessing the config but this is not a good
> solution.. If there was available some simple arithmetic in the QoS it
> would be better :")
Checking the parent rate/ceil will eat a lot of CPU cycles.  That's why HTB is 
ignoring the parent rate/ceil.  It can be done, but it will be bad for 
performance.

Stef

-- 

stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
     #lartc @ irc.oftc.net

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