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seanyseansean
13-04-2008, 18:12
Hi,

Do you take issues for the business service here?

We are experiencing large amounts of packet loss going to the internet from my workplace. We have a managed ntl/tw service, which means they manage a cisco 3700 in front of our own firewall. This cisco box connects to a nokia cable modem out to the ntl/tw network.

The Cisco box seems to be dropping connections at will. This makes my users in the office think the service is slow, because connections keep timing out. As far as I can tell the issue is the Cisco box terminating connections too hastily.

I asked ntl/tw about this and they claimed they'd looked at our Cisco (we cant login to it ourselves) and nothing was wrong. They did say it was receiving a lot of 'bad packets' from our firewall, which frankly seems boll**ks. We have a vpn to Frankfurt through this service and that seems fine, possibly because all traffic through there is one connection to the Cisco box, so it sees it as high priority and doesn't mess with it.

Is there anything I can do to prove to ntl/tw that their cisco box is at issue? Tech seem hopeless, and it feels like i've been fobbed off.

FYI this doesn't just happen when the connection is maxed out - i'm sat here on a sunday, with a minimum of hosts on the network and the utilization of our connection is less than 1MBit of our 8Mbit service, and i'm still getting the problems.

In fact, a putty session to my home server just aborted - I never have this problem from anywhere else, even at my girlfriends home virgin connection.

Thanks for any help!

Sean

cybernetic_tiger
14-04-2008, 09:08
We have a managed ntl/tw service, which means they manage a cisco 3700 in front of our own firewall. This cisco box connects to a nokia cable modem out to the ntl/tw network.


Hi Sean,

Are you ex-Telewest or ex-NTL?

As far as I was aware there are no Nokia cable modems. If you are an ex-Telewest customer the Nokia box is a DNT2 which is a 2Mb copper BNC
to x.21 Network terminating unit.

Also about the priority of traffic, we as a company never trust customers tags. We will re-tag the traffic on the Cisco using the rules set out in the access control lists.

It sounds like the transmission is fine as the VPN to frankfurt is up and stable so it may just be a policy map issue on the cisco (if there is one set up).

I'm also pretty sure that the only Cisco devices ex-NTL installed with cable modems was a Cisco 924 as this had a DOCSIS cable modem built in,

Hope that helps,

CT

seanyseansean
14-04-2008, 09:15
Hi Sean,

Are you ex-Telewest or ex-NTL?

As far as I was aware there are no Nokia cable modems. If you are an ex-Telewest customer the Nokia box is a DNT2 which is a 2Mb copper BNC
to x.21 Network terminating unit.

Also about the priority of traffic, we as a company never trust customers tags. We will re-tag the traffic on the Cisco using the rules set out in the access control lists.

It sounds like the transmission is fine as the VPN to frankfurt is up and stable so it may just be a policy map issue on the cisco (if there is one set up).

I'm also pretty sure that the only Cisco devices ex-NTL installed with cable modems was a Cisco 924 as this had a DOCSIS cable modem built in,

Hope that helps,

CT

Thanks!

The Nokia box is a DNT2M.

From what the problem *looks like* to me, I think it is the Cisco. VPN traffic is okay because it's always busy (as all the data through it seems to only be one connection to the Cisco), it seems as if the Cisco is just too happy to close connections.

Is there anything I can do to verify this, or at least to utter at the Telewest techs?

Apologies for being vague, this kit was setup before I arrived.

Sean

EDIT: Sorry I forgot to state, we are ex-Telewest.

cybernetic_tiger
14-04-2008, 23:10
If you PM me your company name and postcode I will take a look at your solution when I am back in the office (tomorrow night).

Would also be good if you could provide me a traceroute from your PC to the internet,

Thanks,