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Author Topic: ADSL problem on a Cisco 2651  (Read 4753 times)

Kiro

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ADSL problem on a Cisco 2651
« on: October 16, 2008, 02:54:13 PM »

We currently have two customers both with Cisco 2651XM's configured with a standard ATM WIC card and ISDN BRI card. Both are connected to BT Wholesale provided IPStream MAX Premium DSL services. Both sites are running "c2600-advsecurityk9-mz.123-8.T3" as their IOS. The routers are both configured with PPP and Virtual Access 2 is currently up/down. The strange part comes when I do "sh dsl int ATM0/0". On the downstream the router reports the DSL using interleaving and on the upstream using fastpath. As far as I'm aware this is impossible but BTWS are saying the circuits are configured correctly and they can see no problems. Both circuits have also been rebuilt. Has anyone come across this issue before or know how to resolve it?

Attached is a small section of the output from the router. Debug PPP negotiation and Debug PPP authentication are both on.
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roseway

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Re: ADSL problem on a Cisco 2651
« Reply #1 on: October 16, 2008, 03:57:29 PM »

Hi and welcome.

I'm afraid I know less than nothing about Cisco routers, and I don't think I've encountered interleaving on downstream only, but is it actually a problem that needs resolving? Presumably the connection is working normally in both directions, or have I misunderstood?
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  Eric

kitz

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Re: ADSL problem on a Cisco 2651
« Reply #2 on: October 16, 2008, 03:58:04 PM »

Do the routers report interleaving depth by any chance?

Whilst Im not 100% certain that this may be your answer - on some routers you sometimes see Interleave depth/delays of 4 being still reported as being FAST mode.

There are different rates for both the upstream and downstream interleaving.  Downstream uses higher frequencies and therefore is more likely to be affected by noise than upstream.
Downstream interleaving depths are 4,8,16,32,64
Upstream depths I've seen are 2,4,8.
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Kiro

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Re: ADSL problem on a Cisco 2651
« Reply #3 on: October 16, 2008, 04:10:52 PM »

Unfortunately it's not actually connecting, otherwise I wouldn't be too bothered. From what I can see and have been told the LCP requestes are going out but the router isn't receiving any LCP frames back. It's not even got the point where it sends out it's username/password.
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roseway

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Re: ADSL problem on a Cisco 2651
« Reply #4 on: October 16, 2008, 04:24:35 PM »

So it's syncing with the exchange but failing to negotiate a PPP connection. Has this configuration ever worked, or is it a new setup?
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  Eric

kitz

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Re: ADSL problem on a Cisco 2651
« Reply #5 on: October 16, 2008, 04:35:23 PM »

>> Oct 15 17:35:41: Vi2 PPP: Authorization NOT required

Im afraid I dont know much about Cisco's either.. but that looks  strange to me.
PPP authentication and authorisation is required for IPStream adsl, its actually a 2 part process with BTw, then the ISP.

Sync is a different state and attained between the exchange and your router.
PPP is authorisation out "on to the internet".  Therefore if you cant get PPP then that points to something wrong with the router config settings or the ISP logon process/username/password.
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Ezzer

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Re: ADSL problem on a Cisco 2651
« Reply #6 on: October 16, 2008, 05:20:40 PM »

I have a vague memory of possibly this.

one which I had to adjust some settings as the routr had the wrong software fo the site it was being fitted to (I remember this as I had to repeatedly have to tell the first level help desk I'm in Norwich not Chester, due to the references on the router that arrived on site..... well whenever I hear "Computer say's No"  >:(

The other occasion was due to the fact the router insisted on using dsl for up or downstream (can't remember which so long ago) and one of the ISDN lines for the other.

On both occasions a tech desk e-mailed some software to me so I could load it on the router but making a few modifications first.

Sorry I can't be any ore specific as I didn't have a clue what i was doing, just following instructions over the phone, but the problem you mention rings distant bells.

Incidentally, yours hasn't anything to do with the NHS N3 project ?
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Kiro

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Re: ADSL problem on a Cisco 2651
« Reply #7 on: October 16, 2008, 05:36:21 PM »

So it's syncing with the exchange but failing to negotiate a PPP connection. Has this configuration ever worked, or is it a new setup?

The circuit was DataStream but was migrated to IPStream quite recently. The circuit was working for a period with PPP on the DataStream, but since switching to IPStream itís never worked. Itís what makes me think this issue is BTWSí end but at the same time thereís a potential IOS issue here Iíve not had a chance to sort. Itís syncing as 8meg down with interleaving and 832 up on fastpath.

>> Oct 15 17:35:41: Vi2 PPP: Authorization NOT required

Im afraid I dont know much about Cisco's either.. but that looks  strange to me.
PPP authentication and authorisation is required for IPStream adsl, its actually a 2 part process with BTw, then the ISP.

Sync is a different state and attained between the exchange and your router.
PPP is authorisation out "on to the internet".  Therefore if you cant get PPP then that points to something wrong with the router config settings or the ISP logon process/username/password.

I know our RADIUS is fine; the profile for the customer matches the router. Thing is weíre not even seeing the request come in, so either BTWS arenít forwarding it or BTWS arenít getting their request to authenticate the domain. The second is more likely because Iím seeing empty RADIUS results on BTWS.comís tester and I get the same output from the debug when using the CBUK@startup_domain.

I have a vague memory of possibly this.

one which I had to adjust some settings as the routr had the wrong software fo the site it was being fitted to (I remember this as I had to repeatedly have to tell the first level help desk I'm in Norwich not Chester, due to the references on the router that arrived on site..... well whenever I hear "Computer say's No"  >:(

The other occasion was due to the fact the router insisted on using dsl for up or downstream (can't remember which so long ago) and one of the ISDN lines for the other.

On both occasions a tech desk e-mailed some software to me so I could load it on the router but making a few modifications first.

Sorry I can't be any ore specific as I didn't have a clue what i was doing, just following instructions over the phone, but the problem you mention rings distant bells.

Incidentally, yours hasn't anything to do with the NHS N3 project ?

Yeh the software angle has crossed my mind, but the config templates we use are standardised. However as Iíve previously said I am going to the IOS updated. Failing that Iíll swap the router out for a new one. The router does have two ISDNís as backup which is how I access the router but I donít see those causing the problem. And yes I do work on the NHS N3 project, as a second/third line tech for our provision team. Why do you ask?
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Ezzer

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Re: ADSL problem on a Cisco 2651
« Reply #8 on: October 16, 2008, 06:01:27 PM »

it's of of the two main projects I've seen this router, both the exsamples I mentioned were N3 projects. They were all preconfigured so I just had to physicaly fit them and go through the support call structure to have them initalised and tested so we were never trained on the settings side of them.

We either arrived on site with a box already there with a step by step idiot proof instruction sheet or pick the box up from a distribution point. Due to the penalties of over-running he due by instalation of the whole project we were flying all over the place fitting them, hence our fitting them as well as Global and with the 3 problem ones I had rather than wait for a new one being sent out we'd try and do a on site fix with me being the tech desks pair of hands.

I was curious about the software as when I had a set e-mailed to me to load on a router the size of the file vertualy killed my laptop.
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Ezzer

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Re: ADSL problem on a Cisco 2651
« Reply #9 on: October 31, 2008, 04:34:04 PM »

Kiro, just out of curiosity where was the problem router, East Anglia ? Just that I've been on an N3 fault (checking to see if the moons turned blue   ::)). It was a curious one :hmm:
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