Package priority

[julianov403]

Hello All. 

Im looking for a way to analize the IP package priority. Someone can says that the TOS on the IP headers is for that purpose but I dont sure if the app developers take that in account and also, if all ISP works whit TOS on mind. 

Is there another way to check it? for example, we can say that a priority package is one that is sends to an IP address with a fixed size and the package transmision to that IP is made in a fixed time. I mean, there is a package every 125 microsecond. So, that service has more priority than other send to another IP with has not a fixed time delay, 

Thanks 

[Francesco Molino]

Hi

All QoS policies are based on DSCP or TOS.
To catch a specific traffic sent from or to or both IPs, you can make an acl and then with a class-map cat all this acl traffic to set a tag dscp for example.
Then across your network, you can apply a policy to prioritize this specific tagged packets.

[julianov403]

Thania hoy very muchas sir.

Just the last thing. I saw that sometimes the QoS rules is apply checking
the transport layer protocol (if its UDP le TCP for example). Whats the
different regarding use TOS and that? What have ( or is better) to apply
for an autonomus system. I mean, a core network.

[Francesco Molino · Accepted solution]

Using match protocol like tcp and udp is how to classify the traffic like using an acl.

TOS (DSCP) is the tag you define for your packets to prioritize them, in your case, using class-maps