how to ensure ip precedence settings is correct?

[leowchongwei]

Hi,

How can i ensure the ip precedence settings on my router is not changed as it enters ISP's MPLS cloud? Any tools or software to test this?

Rgds,

Steven

[Harold Ritter]

Yous SP will most probably not change the ip precedence in the IP header of the packets entering their network but they might set a different value for the exp bits without you knowing it as the the ip traffic exiting their network will have the original ip precedence.

For instance they could set the exp bits to 0 if you don't pay for any QOS. It is not uncommon. It is hard to tell since you haven't access to their network. The easiest way is probably to ask them.

Hope this helps,

[leowchongwei]

i have asked them already. eg ip prec = 2 for priority traffic, else will be set to 0 for other traffic.

now that i have set the ip prec in my router, is there no way to tell if the ip prec is 2 or 0 when entering their network?

[Harold Ritter]

One way would be to set a network sniffer on the link to your provider. Not realistic though ;o) You can set a network sniffer on a LAN in a remote site, generate traffic for that remote subnet and then see if ip precedence is set correctly in incoming packets on that remote LAN.

Hope this helps,