On the outbounds side the ISP has already incurred the expense of transporting the outbound data to the edge router the customer is connected to. So delivering the traffic within reason would be in everyone's best interest.
On the inbound side the pricing model for rate limited service which the customer wanted is such that taking more traffic than they are paying for would be financially unacceptable. Now of course as the ISP you could build into the price of service the overage traffic, but look at what that means....first you need to have backbone capacity for it since your backbone capacity planning metrics/plan won't easily account for drops and usage of various diffserv values mainly since a fully paying customer has much traffic with zero'ed diffserv values and may expect those values to hold true for one of thier egress circuits on your network(IP-VPN or other site-to-site). Then you're incurring expense of upgrading backbone circuits sooner. For most frame services you'll will build this into the cost structure since customers traffic CAN be shaped by the ATM core effectively, it's almost 100% on your network so the unit cost for bits above committed rates are much lower, and there are a controlled set of sink/sources based upon the PVC's the customers has purchased to make the capacity planning problem slightly more constrained. Hope this helps to explain why shape outbound and limit inbound. Of course there are good arguements for doing similar services in different ways, I was just trying to give the background for why many folks choose this method. Darrell ""YASSER ALY"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > It's my turn to disagree :). If we are going to consider quality of > service from ISP point of view then don't you think that rate-limit is > giving you the advantage of passing exceding traffic for your client > after marking it such that if you do have free bandwidth as the ISP you > can let this traffic through, and drop it if not? Using rate-limit in > such a way means that you can think of charging your client more for > giving him such an option. > > This is not acheivable using traffic-shapping as it just sets a > threshold and drops packets exceeding that threshold. > > What you are doing means to me that you find traffic-shapping is better > than rate-limitting so you are applying it on the outgoing traffic to the > client. However, as it is unidirectional and you can't rely on asking the > client to do it from his side also for the other direction so the only > alternative is to rate-limit on the incoming traffic. > > Would you kindly explain to us why you find your way would provide a > better quality from the ISP ? > > Regards, > > Yasser > > >From: Jay Greenberg > >I would have to disagree. From an ISP standpoint, > when we supply a >capped service to a customer, we use a combination of > rate-limiting and >traffic shaping. I Rate-limit the input, and traffic > shape the output. >I suppose it is more resource-intensive on our end, > however don't you >agree that it is better quality of service from the > ISP? > >On Sun, 2002-09-01 at 04:29, YASSER ALY wrote: > > Rate-limiting > is what we call policing and it is done from the ISP side. > > It is > bi-directional so you can rate limit input & output. You can define > > > what is the policy to be followed when traffic is within range and what > > > to be done once exceeded like pass, mark, drop. > > > > > Traffic-shapping is done from the client side and it is unidirectional ( > > > Controlling the outgoing traffic from an interface. Shapping helps > when 2 > > sites are communicating with each other, one of them is 1M > while the > > other is 256K, traffic shapping would be defined from the > 1M side inorder > > not to flood the 256K link and lots or retransmission > occurs. > > > > >From: "Mohamed Saro" > >what is the difference and the > direction of > > rate-limit and traffic shapping > >FAQ, list archives, > and subscription > > info: http://www.groupstudy.com/list/cisco.html > >Report misconduct and > > Nondisclosure violations to > [EMAIL PROTECTED] > > > > > ------------------------------------------------------------------------ > > > > > Chat with friends online, try MSN Messenger: Click Here > > > > > > archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > > Report misconduct and > Nondisclosure violations to [EMAIL PROTECTED] > > > > ------------------------------------------------------------------------ > > Chat with friends online, try MSN Messenger: Click Here Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=52673&t=52468 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
