Customer oversubscription levels
This might be a dumb question, but I can be sure that I'll be told if that's the case, so here goes: What's a good oversubscription ratio for customer traffic to global Internet bandwidth these days? I.e., if you have, say 90megs of bandwidth to other transit providers, how much bandwidth, in aggregate, are you selling to customers -- 90? 450? 900? Do customers care about this? Or do they assume that if they get a T1 to the Internet from you that they have their own T1's worth of non over-subscribed bandwidth to your transit providers? Thanks, Mathew
Got to think most customers assume oversubscription. Having been on the provider end of this in a previous life, how it often goes is like this. The customer will think/feel they are not getting what they are paying for. As a result the customer will deliberately try to peg their ckt at the bw you say you are selling them, and if they cannot achieve it, they call you and complain. You at that point need to fix it or risk losing the customer. As you sell higher and higher bandwidth rates, the customer's tolerance, presumably because of what they are paying you, goes down. Brian On Tue, 28 May 2002, Mathew Lodge wrote:
This might be a dumb question, but I can be sure that I'll be told if that's the case, so here goes:
What's a good oversubscription ratio for customer traffic to global Internet bandwidth these days? I.e., if you have, say 90megs of bandwidth to other transit providers, how much bandwidth, in aggregate, are you selling to customers -- 90? 450? 900?
Do customers care about this? Or do they assume that if they get a T1 to the Internet from you that they have their own T1's worth of non over-subscribed bandwidth to your transit providers?
Thanks,
Mathew
By now, I think it's widely accepted that it really isn't "oversubscription" or "overselling" until congestion starts becoming an issue. Up until then it's "statistical multiplexing". On Tue, 28 May 2002, Brian wrote:
Got to think most customers assume oversubscription. Having been on the provider end of this in a previous life, how it often goes is like this. The customer will think/feel they are not getting what they are paying for. As a result the customer will deliberately try to peg their ckt at the bw you say you are selling them, and if they cannot achieve it, they call you and complain. You at that point need to fix it or risk losing the customer. As you sell higher and higher bandwidth rates, the customer's tolerance, presumably because of what they are paying you, goes down.
Brian
On Tue, 28 May 2002, Mathew Lodge wrote:
This might be a dumb question, but I can be sure that I'll be told if that's the case, so here goes:
What's a good oversubscription ratio for customer traffic to global Internet bandwidth these days? I.e., if you have, say 90megs of bandwidth to other transit providers, how much bandwidth, in aggregate, are you selling to customers -- 90? 450? 900?
Do customers care about this? Or do they assume that if they get a T1 to the Internet from you that they have their own T1's worth of non over-subscribed bandwidth to your transit providers?
Thanks,
Mathew
James Smallacombe PlantageNet, Inc. CEO and Janitor up@3.am http://3.am =========================================================================
I'd look at this slightly differently.. customers wont use all their available bandwidth at once anyway so you will get aggregation simply by economy of scale. Compare to say the PSTN, there might be say 100000 local customer lines attached to a particular exchange and yet the capacity out onto the trunk network might be say 5000 lines. Clearly there is a high degree of over subscription and phone customers are the first to complain when they cant dial out and yet it doesnt happen because not everyone uses it at once. The same is true for bandwidth, you can achieve a good level of aggregation - say 5:1 and yet each customer can max out their own link because they dont all do it at once The problem comes when you either just dont have trunk capacity or you try to put far too many customers onto a node. I always call it aggregation vs contention - in one you achieve economy of scale and in the other you knowingly degrade service (within the bounds of an SLA) So, to answer your question, it depends what your selling as to how much oversubscription you can achieve, anything for 3:1 to 20:1 depends on if its transit, leased line, broadband, dialup... but I think you should look more at whether you are actually degrading an individuals service or just achieving aggregation. Steve On Tue, 28 May 2002, Mathew Lodge wrote:
This might be a dumb question, but I can be sure that I'll be told if that's the case, so here goes:
What's a good oversubscription ratio for customer traffic to global Internet bandwidth these days? I.e., if you have, say 90megs of bandwidth to other transit providers, how much bandwidth, in aggregate, are you selling to customers -- 90? 450? 900?
Do customers care about this? Or do they assume that if they get a T1 to the Internet from you that they have their own T1's worth of non over-subscribed bandwidth to your transit providers?
Thanks,
Mathew
Typically Class 4 have an over subscription ratio of 4:1, the biggest Class 4 switches can handle 40,000 DS0s like the AT&T 5Ess or DMS 500 switches. A over subscription ratio of 100000/5000= 20 is too high for PSTN. FYI modem to user ratios are 10:1 on the average. ak "Stephen J. Wilcox" wrote:
I'd look at this slightly differently.. customers wont use all their available bandwidth at once anyway so you will get aggregation simply by economy of scale.
Compare to say the PSTN, there might be say 100000 local customer lines attached to a particular exchange and yet the capacity out onto the trunk network might be say 5000 lines. Clearly there is a high degree of over subscription and phone customers are the first to complain when they cant dial out and yet it doesnt happen because not everyone uses it at once.
The same is true for bandwidth, you can achieve a good level of aggregation - say 5:1 and yet each customer can max out their own link because they dont all do it at once
The problem comes when you either just dont have trunk capacity or you try to put far too many customers onto a node.
I always call it aggregation vs contention - in one you achieve economy of scale and in the other you knowingly degrade service (within the bounds of an SLA)
So, to answer your question, it depends what your selling as to how much oversubscription you can achieve, anything for 3:1 to 20:1 depends on if its transit, leased line, broadband, dialup... but I think you should look more at whether you are actually degrading an individuals service or just achieving aggregation.
Steve
On Tue, 28 May 2002, Mathew Lodge wrote:
This might be a dumb question, but I can be sure that I'll be told if that's the case, so here goes:
What's a good oversubscription ratio for customer traffic to global Internet bandwidth these days? I.e., if you have, say 90megs of bandwidth to other transit providers, how much bandwidth, in aggregate, are you selling to customers -- 90? 450? 900?
Do customers care about this? Or do they assume that if they get a T1 to the Internet from you that they have their own T1's worth of non over-subscribed bandwidth to your transit providers?
Thanks,
Mathew
Yeah sorry should have included a disclaimer! My numbers for PSTN were made up as I dont have any real figures to hand or in my head .. it was more the analogy I wanted to demonstrate as people seem to understand aggregation in local exchanges better than bandwidth contention even tho its the same really.. Ok real life.. How about we have about 200 extensions on our PBX but only 30 lines onto the provider network and yet we never see engaged... Steve On Tue, 28 May 2002, Arman wrote:
Typically Class 4 have an over subscription ratio of 4:1, the biggest Class 4 switches can handle 40,000 DS0s like the AT&T 5Ess or DMS 500 switches.
A over subscription ratio of 100000/5000= 20 is too high for PSTN.
FYI modem to user ratios are 10:1 on the average. ak
"Stephen J. Wilcox" wrote:
I'd look at this slightly differently.. customers wont use all their available bandwidth at once anyway so you will get aggregation simply by economy of scale.
Compare to say the PSTN, there might be say 100000 local customer lines attached to a particular exchange and yet the capacity out onto the trunk network might be say 5000 lines. Clearly there is a high degree of over subscription and phone customers are the first to complain when they cant dial out and yet it doesnt happen because not everyone uses it at once.
The same is true for bandwidth, you can achieve a good level of aggregation - say 5:1 and yet each customer can max out their own link because they dont all do it at once
The problem comes when you either just dont have trunk capacity or you try to put far too many customers onto a node.
I always call it aggregation vs contention - in one you achieve economy of scale and in the other you knowingly degrade service (within the bounds of an SLA)
So, to answer your question, it depends what your selling as to how much oversubscription you can achieve, anything for 3:1 to 20:1 depends on if its transit, leased line, broadband, dialup... but I think you should look more at whether you are actually degrading an individuals service or just achieving aggregation.
Steve
On Tue, 28 May 2002, Mathew Lodge wrote:
This might be a dumb question, but I can be sure that I'll be told if that's the case, so here goes:
What's a good oversubscription ratio for customer traffic to global Internet bandwidth these days? I.e., if you have, say 90megs of bandwidth to other transit providers, how much bandwidth, in aggregate, are you selling to customers -- 90? 450? 900?
Do customers care about this? Or do they assume that if they get a T1 to the Internet from you that they have their own T1's worth of non over-subscribed bandwidth to your transit providers?
Thanks,
Mathew
participants (5)
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Arman -
Brian -
Mathew Lodge -
Stephen J. Wilcox -
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