Troubleshooting Latency - European IP Clear

Hi everyone,

I have been looking at a specific problem with one of our European sites in Germany for the last couple of weeks. We connect to them via IP Clear and the carrier is (no secret here...) BT.

Both sides are using Cisco 3620 routers which are working fine. My users starting experiencing some slowness a couple of weeks ago and when I pinged some servers and the router down there I can see some delays throughout the day.

I use Solarwinds for monitoring the health of the LAN and WAN utilisation and the WAN link looks well under the threshold while LAN shows no errors.

As we have another 60 sites all over Europe with similar configs, I am pretty sure the router config is fine...

My question is: do you reckon it is possible for this latency to be cause by the BT 'cloud' between London and Germany and if you do what would be a good test of proving it...

Thanks in advance,


Reply to
Johnny Noitargim
Loading thread data ...

What speed is the link?

Is it Frame-Relay or ATM?

Is it Frame to Frame (unlikely since you are going to Germany), or Frame to ATM to Frame?

If it is a Frame-Relay ckt, what is the CIR and Bc?

Is traffic shaping set up correctly? Are you bursting correctly, are you seeing BECNs?

If it is ATM, do you see CLP=1 cells?

Similar != same

There could be a translation issue in the cloud between the frame and ATM that would be causing latency.

Ask them what kind of switches they are using (they probably won't tell you), but they are probably Alcatel... Tell them to check the path being taken and what the utilization is of their internodal links.

You need to check for latency from serial interface to serial interface. SolarWinds is going to be testing through your LAN, you need to rule that out befor eyou start screaming at BT (unless screaming at BT gives you pleasure)...

Check the CPU utilization on the router, check the interface flows (ethernet to serial) to make sure you don't have a virus snarfing all your bandwidth...

BT probably has a latency SLA of 100ms from edge switch to edge switch, tell them your ping times (this is based on a 100-byte packet)...

Realistically, you need to take a look at the SLA from BT and see what they are guaranteeing (you probably need to convert the bytes and miliseconds into metric or something first tho...)


Reply to
Jonathan Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.