GE MDS ORBIT ECR, Technical Manual

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MDS 05-6632A01, Rev. F MDS Orbit MCR/ECR Technical Manual 297
This will set up a policy that prioritizes all traffic with the ether-type of
0x88b8
above all else. Showing
the config should display:
% show services qos
enabled true;
policy Policy1 {
prioritization {
default-priority 5;
class HIGH {
priority
1;
classifier [ GOOSE ];
}
class STANDARD {
priority
5;
}
}
}
classifier GOOSE {
match M1 {
ethernet {
ether-type {
protocol
goose;
}
}
}
}
This policy has to be applied to an interface before it has any affect. To apply the policy to an interface:
% set interfaces interface NxRadio qos output Policy1
Now all traffic going out of interface NxRadio will prioritize based on Policy1.
Example: Priority Inversion
Suppose all traffic from IP address 1.2.3.4 needs to be prioritized above all else, unless it is SFTP traffic.
SFTP traffic from anyone has to be prioritized at the lowest priority. To start with we will set up the
classifiers and the policies.
% set services qos classifier SFTP match M1 ipv4 protocol assigned-number tcp
% set services qos classifier SFTP match M1 ipv4 dst-port services ssh
% set services qos classifier FROM1234 match M1 ipv4 src-address address 1.2.3.4/32
% set services qos policy Policy1 prioritization class HIGH priority 1 classifier FROM1234
% set services qos policy Policy1 prioritization class BULK priority 15 classifier SFTP
% set services qos policy Policy1 prioritization default-priority 5
This creates a policy with three classes where unclassified traffic will go into the second priority class.
The class priority numbers do not imply the number of underling classes, just the order of the classes'
priority. The default priority can be the same as a defined class, but if it's not a class is created under the
hood with no classifier or next policy.
The problem with this configuration is that because we check for matches in order of priority we will
match on the IP address of 1.2.3.4 and apply the mark for the high priority class before we check if it is
SFTP. One solution to this is to use the classifiers metric. A classifier with a lower metric is evaluated
before classifiers with higher metrics. All classifiers have a default metric of 10. So by giving SFTP
classifier a lower metric, it will be considered before the FROM1234 classifier.