linksys SPA9000 and SPA942 bandwith and route queries

[wfitz]

Hi all,

Query:
1) bandwidth that should be reserved for 2 phones

2) nat? do i need it?

NETWORK SETUP:

provider Digiweb
3MB Download, 384kbps upload

Digiweb STATIC WAN IP

Internal (192.168.1.X) STATIC IP's for PBX and 2 Phones.

Zyxel P660HW-D1 digiweb dsl-modem/router/4-port switch/firewall/wireless AP. this is the one digiweb supply and the only one they support. it has QoS so it should be fine. it doesn't seem to have a DMZ function but that shouldn't matter.

Zyxel --> port 1 to Linksys 8-port switch
port 2 to linksys PBX SPA9000
port 3 to linksys SPA942 VoIP phone
port 4 to linksys SPA942 VoIP phone

Linksys 8-port switch --> port 1 linked to zyxel router
--> port 2 to server (static internal IP)
--> port 3 to PC (dynamic IP)
--> port 4 to Laptop (dynamic IP)
--> port 5 to printer (dynamic IP)

BANDWIDTH or QoS QUESTION:
what kind of bandwidth do i need to reserve for the 2 phones? i left the default settings on the SPA9000. i am not sure of codec etc but its the default.

i presume the download requirement is the same as the upload for VoIP.

network comsumption in general:
server accesses the internel for software updates and virus updates.
PC and Laptop light www browseing and email. email hosted off site at digiweb. i just use outlook to pop send send email from digiweb on PC and Laptop.

As far as i can tell the ZyXEL router (it has QoS) can do basic bandwidth priority constraints HIGH,MED and LOW and further on in the manual it seems to get more complicated. However it may just be as simple as (basic way) traffic types:
VoIP = High, www =Med, email = med

NAT QUESTIONS:
I have not altered any NAT stuff on router. i think it is blank if i remember correctly (i am offsite at the moment).

I seem to be able to make and recieve calls but i have not set up nat and the firewall is enabled by default on the router.

So do i play around with NAT and try and figure out what i need to do here or is it ok to forget about NAT?

NOTES:
last friday when i installed everything i had everything behind the switch, that is phones and computers. but on monday afternoon all phones calls where either dropped or quality was so bad no one could hear each other. So i then moved all phones and PBX to router and kept computers behind switch.

its seems to be going ok with only the odd interruption. thats why i want to apply QoS to aleast make sure i can make calls.

Also, i have the internent port of the PBX plugged into the router and not the ethernet admin port. thats ok isn't it?

any further suggestions on my current network setup, default router and default PBX settings are most welcome.

I can be emailed directly at:
wfitzgerald(at)tssg.org

but a reply to the forum would be benificial for others having similar issues.

looking forward to hearing your advice,
Will.