Routers queues size..does it mater?

hey all.
I am writing a paper about routing. A non-expert work...
I handed to my teacher and he gave it back to me, it neads some adjustments...
When i mention that routers may have different queue size he just asked me: "Why? What do we gain with that policy?"

I couldn't give him a answer, i didn't know it, in fact i am still looking for it everywhere on the web and i can't find it.
Can anybody help me please?

The question is simple:

Why do routers somtimes have small queues instead of larger onde and vice-versa??


thank you.

well it may not be the exact answer, but as with anything with memory and a processor it's an efficiency equation. If you have a smoking fast processor and a lot of free memory, then a large queue would be an advantage. But if it's a slower model with less ram, a larger queue would take longer to process than a small queue.

hey waldo, thx.
That makes sense, that way things can speed up a litle.
If anybody has a diferent opinion, any help would be apreciated

I would imagine that it might also have something to do with network traffic and collision control. If you have a small queue, it waits for less time in the queue to be moved on. So the object is to shove it through almost immediately or send a response back saying to try again, so you don't sit there and wait and wait and wait and THEN get a response back that it hasn't gone through yet. Plus, if you're doing throughput calculations, a smaller queue will have a higher throughput over a short amount of time.

I think there was something in my networking book when I took the class about queue sizes and the fact that there is an optimal size that is set for a queue.... and as waldo said, it all comes back to efficiency and timing.

i see...
by the way....wich network book did you had?
Maybee i can have a look on it if i can find it on the library or something

I have no idea... that was over 2 years ago and I don't have the book anymore.

btw, what kind of routers are you talking about, routers in general, cisco aeronets, etc?

Routers in general.

I would refer you to www.howstuffworks.com. Maybe it's just because I saw them featuring an articles on routers recently - but they go to a lot of detail and may be able to help with this paper. In any case - it's a really interesting site.

i know that site very well but usualy go there just when i need to have the first knowledge about any subject... anyway it impressed me with som much information about routers. But still focus on basic knowledge, it's a comom snse site, it couln't be other way.

By the way here are some good sites from which i got some good documentation

www.dataconnection.com
www.cisco.com (fundamental)

Any more answers to the mais question on this thread are wellcome and apreciated.