Hardware Queue only for egress in the interface?

Routing & Switching Quality of Service
1

I have questions:

  1. Is only hardware queues in outbound (egress queue) of the interface?

    • So, has the egress both hardware queue and software queue?
    • While ingress has only software queues?

  2. When the queuing policy say ‘1p2q2t’ (one Strict Priority Q, two Standard Q, two WRED thresholds),
    does it mean only for hardware queue?

I am very confused.
Thus, I would appreciate if you answer it as soon as possible.

Thanks,
Whijoon

2

Hello Whijoon

Hardware queues can be both incoming and outgoing (ingress and egress). Any queue types that are described in such notation as 1p2q2t are hardware queues. Not all devices support them, and not all devices support all types.

These queues are distinct from software configured queuing techniques such as those configured in the following two lesson.

I hope this has been helpful!

Laz

3

Hey Laz, Im realy confused right now.

In one post / lesson you are stating that hardware queues are faster then software queues, and that switches such as the cat 3560 can be configured with QoS only on their hardware.

Could you explain it to me?
I was sure 100% that 1p2q2t indicate what are the supported hardaware-queues on a switch and what are they capable of, until now…

WFQ can have thousand of queues in software from my understanding, and with MQC we can configure as much classes as we want for different queues as we wish for through the software.

4

Hello Nitay

You are absolutely correct the 1p2q2t does indeed indicate the capabilities of a hardware queue. Looking back at my answer of two years ago, I don’t remember my logic behind this at all.

The following Cisco documentation further describes these hardware queues types and what they mean.

I have since corrected my answer above. Thanks for pointing it out!

Laz

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