Adding a subnet for QoS

Ok, I'm a new network administrator, so I'm still figuring out what all our IP addresses and ranges are and whatnot, so therein lies part of my problem. To start off with, I have the following error to deal with:

Event Type: Warning
Event Source: RSVP Event
Category: None
Event ID: 10035
Description: This host can not be ACS since the Active Directory directory service has not been properly configured via the QoS ACS management console. Please configure the subnets via the QoS ACS management console.

After doing some investigation, I learned that the way to resolve this problem is to properly configure the QoS service by adding a subnet. When adding the subnet for QoS, I'm supposed to enter it in the following format:

IP address/subnet mask width in bits (for example, 192.168.16.0/24)

So my question is: How do I figure out what to enter for the subnet? Where do I look? What about for the unmasked bits (/24 in above example)?

What you enter depends on your ip addresses and how they are subnetted, so in theory what you are asking about is the basics behind subnetting. There are several tutorials around AO and many more sitting on the internet. Look at your routers configuration and see how it's set-up, take a look at your PCs and see how they are networked and what they're ip addresses and subnet masks are set to...

If you're hosts are all straight 192.168.0.*** addresses with a subnet mask of 255.255.255.0, then it is fairly straight forward your subnet address is 192.168.0.0 and your subnet mask is 255.255.255.0 which is 24 bits, so your Network Address/Bits would be 192.168.0.0/24

The /24 comes from the subnet mask, count the number of lit up bits. It can be a max of 32 which would specify a specific host. (255.255.255.255 or /32 or 11111111.1111111.1111111.1111111)

/20 would be 255.255.240.0 (11111111.11111111.11110000.00000000)
/16 would be 255.255.0.0 (11111111.11111111.00000000.00000000)
/8 would be 255.0.0.0 (11111111.00000000.00000000.00000000


it could start getting tricky and you could have something like
192.168.0.0/28 (255.255.255.11110000)
192.168.0.16/28
192.168.0.32/38
192.168.0.48/28
and so on as you work through the subnetting.

I suggest you read through the subnetting tutorials on this site because I don't feel like writing a complete tutorial but this should get you started.


peace

Do you know the broadcast or gateway address of that particular subnet?
If so then it should be pretty straightforward obtaining the subnet mask.