SRX

Hi everyone,

Please consider the following set up:

Let say we have mapped 8 traffic class to queues on our SRX 650

Traffic 0—Q0

Traffic 1-q1

Traffic2-q2

Traffic3 q3

Traffic4-q4

Traffic5-q5

Traffic-q6

Network Control-q7

If we do not define any scheduler,  will SRX  service queues from high to low queue using default scheduler?

How about if we want to modify this order for example:

Traffic 0—Q0

Traffic 1-q1 Scheduler 1, priority high

Traffic2-q2 Scheduler 2 priority low

Traffic3 q3 Scheduler 3 priority low

Traffic4-q4 Scheduler 4 priority low

Traffic5-q5 Scheduler 5 priority medium

Traffic-q6 scheduler 6 priority low

Network Control-q7 scheduler 7 priority low

Will the above config cause queues be serviced in following order?

Q1 first ( because Scheduler priority is high)

Q5 second ( because Scheduler priority is medium)

Then rest of them in these order

Q7

Q6

Q4

Q3

Q2

Q0

Thanks and have a nice day!!

Default schedulers looks like that:

[edit class-of-service]
schedulers {
	network-control {
		transmit-rate percent 5;
		buffer-size percent 5;
		priority low;
		drop-profile-map loss-priority any protocol any drop-profile terminal;
	}
	best-effort {
		transmit-rate percent 95;
		buffer-size percent 95;
		priority low;
		drop-profile-map loss-priority any protocol any drop-profile terminal;
	}
}
drop-profiles {
	terminal {
		fill-level 100 
		drop-probability 100;
	}
}

It is implicit. It doesn't show in the configuration.

best-effort is assigned to queue 0 and network-control to queue 3. No other queues have resources assigned to them.

Assigning forwarding-classes to queues will do nothing untill you also assign resources.

If you assign resources and priorities traffic will be forwarded based on WRR Weighted Round Robin. From hight to low (strict-high is an exception and is always serviced first). Priorities matter as logn as traffic is in profile (doesn't exceed assigned resources).

Regards, Wojtek

Thanks,

 I just edited this post based on the" Day one book on COS"

Basically , I am trying to understand what controls the order,  queues  are serviced by scheduler? Is it scheduler's  priority ? is the queue's  priority?

Queue priority:

class-of-service { forwarding-classes {

class NC queue 7 priority high;

class EF queue 5 priority high;

class AF11 queue 4 priority low;

class AF13 queue 3 priority low;

class AF22 queue 2 priority low;

class AF42 queue 1 priority low;

class BE queue 0 priority low;

class LBE queue 6 priority low;

Scheduler priority:

2) How are the queues seviced if the all scedulers are configured same low priority? will then Queue's prioprity decding factor? How about if all queues are low priority low i.e q0 through q7 are configured as low priority?

Thanks for your response.

Traffic is serviced based on priority configured under schedulers.

Priority configured under forwarding-class is a "fabric priority". It can be either low or high. It is used when you have fabric oversubscription.

Regards, Wojtek

Thanks for your response.

 What if all schedulers for tarffic classes, (mapped to queues 0-7), have same priority? Will in that case Queues are serviced from Q7 to Q0?

Thanks nad have a nice day!!