qos standard vs priority vs hierarchical

[Random44F]

Hi all,

I am really getting confused and have read lots of article and still don't fully get the queues on asa.

I know asa can support standard priority and hierarchical but here is what i don't understand

why can I not police priority queue? for instance police standard at 1mbps and police priority at 2mbps . this is so the priority will not take whatevery is available

also what is hierarchical queue as I don't seem to get this one at all.

I appreciate examples for this one

I guess WRED, RED etc are all in the same class of standard,priority queuing etc which are used to manage queues and asa only offers what is mentioned on the title and the priority queue uses low latency queue?

Thanks

[Julio Carvajal]

Hello ,

I will try to explain this as simple as possible:

Standard Priority queue:

It basically splits the interface into 2 different queues (one for low latency traffic and the other one for best effor traffic)

You cannot use shaping in here, altough you can use Policing just for the best-effort traffic

Hierarchical Priority configuration, when it's need it?

It needs to be used when you enable traffic shapping on an interface and you want to use a LLQ. that's all... so that some traffic that is being shapped can be prioritized.

why can I not police priority queue? for instance police standard at 1mbps and police priority at 2mbps . this is so the priority will not take whatevery is available

Well, that's just the desing of the firewall, I mean this is not a device that I would recommend to purchase to implement QoS in the network but at least it allow us to provide some basic mechanisms need it to have QoS end-to-end up and running.

I know that with the MQC on a router you will be able not just to determine which traffic will get to the priority queue but also provide it certain limit of bandwith so it does not overwhelm the other queue (best effort) but on the ASA you have to think of it like if it were using Custom Priority Queueing where you just select which traffic goes first and that's it.. No option for limiting the traffic on the LLQ.

Cheers,

Julio Carvajal Segura

[Random44F]

Thanks for this and that made sense and helped understand the subject better.

I take it that if we buy a ios router then it can police or shape different queues and use different queuing algorithm such as RED, WRED etc .

Is that a job of router ? If so what cisco router would you recommand to go with for small business which offers most of these functions?

[Julio Carvajal]

I take it that if we buy a ios router then it can police or shape different queues and use different queuing algorithm such as RED, WRED etc .

Is that a job of router ? If so what cisco router would you recommand to go with for small business which offers most of these functions?

Exactly, you got it now.

As per design I would say that when you try to create a device that will be in charge of inspectioning traffic, permiting and denying it you would not focus that much on the QoS side, altough the ASA has pretty amazing capabilities related to QoS as other firewalls does not have.

In this case for a Small businnes router I would go with any of the 2800 series router that you can buy on Ebay/Amazon for a really good prize and you can set it as a really good firewall with ZBFW and then also configure QoS as you want with the Modular QoS CLI,

There you go,

For Networking Posts check my blog at http://laguiadelnetworking.com/

Cheers,

Julio Carvajal Segura