VPN, CIR, QOS and COS for ADSL via cisco 837

cisco_trouble

Hi there people

I have a frame-relay network. 2 E1 with a couple of pvc's running off each link. They load-balancing as well. My concern is that there is a cheaper alternative. Namely ADSL. If you guys can give some input concerning the reliability factor of using ADSL for vpn. And is it possible to have qos, cir and cos on adsl. to my understanding, adsl is best effort and goes via the massive Internet cloud.

They basically trying to sell me, 512 download with 192 upload. 20gig cap and a 32 CIR for each link....

Your help will be appreciated.

EdTheLad

ADSL is a physical standard it has nothing to do with QOS, the bandwidth you acquire on an adsl line depends on distance and interference.The service provider will run a layer 2 protocol, normally atm over the DSL line, hence providing you will a traffic profile.
The DSL line is typically your telephone line, it will run to your POTS and then split.Realiability shouldnt be an issue, but it all depends on your provider.

cisco_trouble

Yeah i understand. But isnt that redundant. At the moment im running FR. So they will be providing a class of service or profile for the ATM over the dsl? Like the ATM over the diginet/martis serial equipment for the Frame relay? Dont see the point, because how do you control broadband by putting ATM over it? for instance, if i have 512download with the broadband...which isnt at all reliable...pure ip. and i have 32CIR over the dsl like you said...which is basically ATM over dsl. The 512 maybe thru congestion can drop to 12kb, how do they gaurentee CIR of 32kb...its realiable ATM running over an unreliable dsl?

EdTheLad

Your question isnt so clear. How it work as as follows.
At your home you will have a dsl modem connected to a DSLAM at the providers side.The dsl modem will train up to the DSLAM and depending on quality of line and distance you will obtain a physical bandwidth on your DSL line.Lets say it trains up and you get 6M downstream and 1M upstream.

On the DSLAM there will be a config for your DSL line mapping it to ATM giving you a certain profile i.e. UBR+ with a downstream PIR 512K and a MIR 64K, and lets say an upstream PIR 256k MIR 32K.
This ATM traffic profile is basically controlling your access to the internet, it will block traffic on the network side from arriving to your DSL line.
Since there are thousands of users on the actual network port of the DSLAM at any given time your profile specifies that you will be guarenteed
a minimum bandwidth of 64k downstream and 32k upstream, in the case that there is bandwidth available due to other users not connected you will share the available bandwith with other users and be able to obtain maximum 512k downstream and 256k upstream.
I dont see why u think dsl is unrealiable??
Now with broadcast video available the whole 6M downstream can be utilised but as you can see the physical bandwidth obtainable is different than what the provider actually give you.

cisco_trouble

True ed_the_lad. You do understand what im saying. But like for home user, you dont get any CIR, you get 512k pipe, but its not gaurenteed right?it can be anything between 0-512k. So basically my profile of 32k CIR means that i can burst up to 512k. As a home user, dsl isnt as reliable as maybe isdn or fr. So other than being cheaper, dsl dont offer anything more. I already have a E1 with a 512CIR, and pvc's running to my remote sites.

So would it be a good choice to move to dsl?

Yankee

We tried moving some of our remote sites from Frame to DSL and found it to be a bad decision. ADSL's bandwidwidth is distance dependent so the numbers at least in the US are best effort and seldom even close to being obtainable. Second problem is customer support for both cable and DSL. It sucks. We have moved to internet T1s from a major provider as an alternative.

Yankee

EdTheLad

cisco_trouble wrote:

They basically trying to sell me, 512 download with 192 upload. 20gig cap and a 32 CIR for each link..

Ok what this means is they will guarantee 32k for each link.Max they will allow you to download is 512K and max upload is 192K.The 20gig cap makes no sense as they are already pinning you down to 512K, so i would
say this is marketing rubbish.Now if this is a new provider for sure they wont have many customers to fill their trunk ports so i would imagine you should recieve close to your max 512 for a while, this all depends on if your Provider is an **** or not! But if the price between what you currently have is not so significant i wouldnt bother changing.

cisco_trouble wrote:

As a home user, dsl isnt as reliable as maybe isdn or fr.

Who told you that? What makes in unreliable in your opinion? in my opinion its the same.I work alot with DSL and have no issues!

cisco_trouble

thanx for the input. But i guess its where you are in the world. south east asia my dsl experience has been hassle free (except for the language barrier), but it depends on your provider. At the moment, dsl is realitively new development, so they pumping the public with dsl this and dsl that...actually to me dsl is good for entertainment and downloads and not for a reliable "always-up" alternative. And yes Yankee, cables and support sucks...
The infrastructure is also not that good where dsl is concerned, and dont want to sit with half dsl and other half FR, just adding more effort.
As for the cap! Its pathetic! SA only has one provider, so its monopoly no choice.

Any1 of u up for a business in providing networking?

cisco_trouble

one last thing. The CIR, QOS and COS are all built upon the underlying ATM layer 2 protocol?

EdTheLad

Yes this depends on what layer 2 protocol your using.CIR,COS is FR terminology while their called SIR(SCR) and service cateory in ATM.
Maybe your provider is using FR on the DSLAM but i dont think its common to use FR, maybe they are just using the FR terminology as its basically the same.

rossonieri#1

cisco_trouble wrote:

one last thing. The CIR, QOS and COS are all built upon the underlying ATM layer 2 protocol?

hello,
i'm sorry not understand your posts quite clear

cisco_trouble

hey bro

what im trying to find out is that all traffic shaping takes place using the ATM protocol or structure and not the physical layer dsl?

rossonieri#1

cisco_trouble wrote:

True ed_the_lad. You do understand what im saying. But like for home user, you dont get any CIR, you get 512k pipe, but its not gaurenteed right?it can be anything between 0-512k. So basically my profile of 32k CIR means that i can burst up to 512k. As a home user, dsl isnt as reliable as maybe isdn or fr. So other than being cheaper, dsl dont offer anything more. I already have a E1 with a 512CIR, and pvc's running to my remote sites.

So would it be a good choice to move to dsl?

pipe is a term on broadband connection only (like cable connection), while DSL is a dedicated connection from which telcos/provider define their own definition (which may vary from country to country). Your leased E1 can be thought as DSL because the definition you owned the whole connection.

An ADSL may be part of DSL.
you dont have a CIR on ADSL? well, not really.

A CIR only a service level agreement that convince your lowest available BW at peak time is at X Kb - and you can burst up to X DE bit at low time.
QOS - you define the traffic, not can QOS with ADSL?
FR to ATM internetworking is providers concern - not the end user.

cheers...

cisco_trouble

Hey people

Thanx a lot for the input. My conclusion is that i will stick to the isdn and FR for a while. Its more reliable and secure. Although dsl is a cheaper advantage, that seems to be it. The bursting to discard eligibility is available for any traffic shaping package, so its not a problem. I just feel that for the moment the telco has more control to gaurentee the latency through FR cloud than to what they offering home users. And thats what they offering, a home user's package with QOS via the ATM.

Cheers people.

EdTheLad

cisco_trouble wrote:

Hey people

I just feel that for the moment the telco has more control to gaurentee the latency through FR cloud than to what they offering home users. And thats what they offering, a home user's package with QOS via the ATM.

Cheers people.

Funny what you are saying,you are contradicting the whole idea behind the development of ATM.FR has more gaurentee of latency through the network!
The reason why ATM was developed was to create a fix sized cell so that latency would be more predictable.
One thing you must take into accout, the CIR that is guarenteed to you via
FR is most probably overbooked by a minimum of 200%, on average FR networks overbooking is usually running at about 400%.

cisco_trouble

oh ok. Bit confused now. You can have WAN and LAN protocols over the ATM right? So my Frame Relay network is going over a ATM backbone right? So my frame relay packet is being encapsulated into an ATM cell, right? So the telco controls the latency in this way right? 53byte cells. I know the FR is overbooked but works with the same pricipal as cellphones, only on christmas is it really congested and no1 gets thru . But the problem i had is what they offering is the dsl or adsl which is a layer 1 technology is being encapsulated into ATM cells...limited to physical layer problems, i.e. distance. so i get what u saying ed_the_lad, you telling me the samething. Just what im getting is layer1->FR->ATM encapsulation. Maybe...i might be missing something .

EdTheLad

Yes WAN and LAN protocols can go over ATM, would i say your ISP is encapsulating FR over ATM, most probably not, you only tend to do this if you are missing specific hardware, so its more of a workaround than anything else. Way too much overhead!
Latency is only an issue when you are using video or voice,its no big deal for data, generally to get around latency in FR the device that encapsulated the data in FR should make smallish farmes, the only problem with small frames is more overhead.So at the end of the day you sacrifice bandwidth for delay.
In your case you use the internet, i.e. data, you will have no problems with latency as internet is a best effort service.
Are you sure the provider is using FR on the backbone? It's one or the other FR or ATM, in your case it really doesnt matter which they use.
The layer 2 protocol is just important to the ISP so they can control the
flow of data to the customer.Now if the provider is offering TV or voice over dsl i'm sure they will use ATM as explained already due to latency issue's.

rossonieri#1

cisco_trouble wrote:

oh ok. Bit confused now. You can have WAN and LAN protocols over the ATM right? So my Frame Relay network is going over a ATM backbone right? So my frame relay packet is being encapsulated into an ATM cell, right? So the telco controls the latency in this way right? 53byte cells. I know the FR is overbooked but works with the same pricipal as cellphones, only on christmas is it really congested and no1 gets thru . But the problem i had is what they offering is the dsl or adsl which is a layer 1 technology is being encapsulated into ATM cells...limited to physical layer problems, i.e. distance. so i get what u saying ed_the_lad, you telling me the samething. Just what im getting is layer1->FR->ATM encapsulation. Maybe...i might be missing something .

come on mannnn....
you do like OSI Layer very much dont you?
on the real world we work with TCP/IP stack which is very much different in implementation than OSI. Encapsulating this - that etc...
shortly - as long you dont have any problemo with your connection - problem solved.

cheers...

cisco_trouble

true. we not using video, pure data basically so timing and latency is not as critical. But its an ATM backbone with frame relay switches that connects to my 2600s. So its ATM with layer 2 FR.

One thing. Internet is best effort, so if im a home user with dsl connecting to the net...its all best effort.

cisco_trouble

haha, u getting a bit irritated? Naah, tcp/ip or osi, they all models..dont really get myself over concerned with it. But helps to know the underlying and "overlying" protocols and encapsulation methods. With configuring and troubleSHOOTING. haha. Naah, problem is money and im trying to get a big bonus...so if i save, i gain!

cisco_trouble

and rossonieri#1 ....liverpool is winning the UEFA Champions League!!! haha