Ethernet Switching
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Trusted Contributor
ttl_expired
Posts: 438
Registered: ‎11-11-2008
0

Hey QoS Experts ur inputs needed

Hey Guys,

 

   I have a quick questions about seting up the EX swiches to perform QoS.  I have read many ariticles and forum posts about this topic and had one question about two distinct methods I have seen for placing the traffic into a forwarding class

 

Method A

 

- Use classifiers which look for specific low code endpoints ( stuff like 01010110) and the like and apply the classifier on every port so that as traffic comes in it is examined for these code points

 

Method B

 

-  In the case of a separate Voice and Data Vlan simply put a firewall filter inbound on the vlan that says any traffic inbound place into Forwarding class X

 

Now Method B seems like its about 800 times easier to implement as you just put one filter in one place.  Does this method work?  No where in the juniper docs does it ever use this method.  they always do the long winded code endpoints on every single interface in the enterprise.

 

 

your thoughts?

 

Thanks!

Recognized Expert
wimclend
Posts: 275
Registered: ‎04-03-2009
0

Re: Hey QoS Experts ur inputs needed

on the edge, you will want to use the firewall filter to put traffic into the proper forwarding class / queue, and then use a rewrite rule to mark the traffic to conform with your network qos markings.  also you'll need the scheduler and scheduler-map as well to specify the servicing

 

then on the next switch (upstream), you would want to configure a classifier on the port that put packets with proper markings into their respective queues.

 

 

note that you CAN use wildcards at the [edit class-of-service interfaces] hierarchy -- so you can use 'ge*' and it will apply it to all interfaces.

 

here's an example that we deployed -- it worked on 9.5 and so far as I know still works today:

 

 

class-of-service {
    classifiers {  ## defining classifiers
        dscp COS-DSCP {
            import default;
            forwarding-class voice {
                loss-priority low code-points ef;
            }
        }
        ieee-802.1 COS-802.1 {
            import default;
        }
    }
    forwarding-classes {  ## defining FC to queues
        class voice queue-num 6;
        class best-effort queue-num 0;
        class network-control queue-num 7;
    }
    interfaces { ## configuring interfaces, notice wildcards
        ge-* {
            scheduler-map COS-map;
            unit * {
                classifiers {
                    dscp COS-DSCP;
                }
                rewrite-rules {
                    dscp dscp_rewrite;
                }
            }
        }
        ae* {
            scheduler-map COS-map;
            unit * {
                classifiers {
                    dscp COS-DSCP;
                }
                rewrite-rules {
                    dscp dscp_rewrite;
                }
            }
        }
    }
    rewrite-rules {  ##configuring rewrite rule
        dscp dscp_rewrite {
            import default;
            forwarding-class voice {
                loss-priority low code-point ef;
            }
        }
    }
    scheduler-maps { ## configuring scheduler-map
        COS-map {
            forwarding-class voice scheduler voice-sched;
            forwarding-class network-control scheduler nc-sched;
            forwarding-class best-effort scheduler be-sched;
        }
    }
    schedulers { ## configuring schedulers
        voice-sched {
            buffer-size percent 5;
            priority strict-high;
        }
        nc-sched {
            buffer-size percent 5;
            priority strict-high;
        }
        be-sched {
            transmit-rate remainder;
            buffer-size remainder;
            priority low;
        }
    }
}

 

 

i'm sure its not the best QOS config, but will hopefully get you going in the right direction.

 

 

good luck!

 

Will

Recognized Expert
wimclend
Posts: 275
Registered: ‎04-03-2009
0

Re: Hey QoS Experts ur inputs needed

oops I forgot the firewall filter and application to the RVI:

 

 

firewall {
    family inet {
        filter qos_classifier {
            term voip {
                from {
                    source-address {
                        10.11.12.0/23;
                    }
                }
                then {
                    loss-priority low;
                    forwarding-class voice;
                    accept;
                }
            }
            term netcontrol {
                from {
                    precedence [ net-control internet-control ];
                }
                then {
                    loss-priority low;
                    forwarding-class network-control;
                    accept;
                }
            }
            term best-effort {
                then {
                    loss-priority low;
                    forwarding-class best-effort;
                    accept;
                }
            }
        }
    }
}


    vlan {
        unit 100 {
            family inet {
                filter {
                    input qos_classifier;
                }
                address 10.11.12.1/23;
            }
        }

 

Will

 

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