VOIP QoS Setup

[lagcat]

Hi People i tried posting this last night but it failed....

this is a long winded thread but please keep with me

we are currently replacing all our random switches with FS728TP so we have a standard model on site (around 30 switches, 200 users, large open site conencted via fibre optic)
we are looking at a VOIP system at the beginning of next year

i need to make sure i make the most out of the switches regarding traffic management

i did not want to set a VLAN up as alot of the phone can connect via the computers which would need to be on the existing subnet

so i am looking at the QoS - on these switches i can only see CoS or DSCP can someone give me a run down of how i can use this with VOIP to manage traffic....i am reading and reading but not enough is sinking in - diagrams would of been easier but can see any that help

i have two options Cos or DSCP:

my view of CoS so far is that you can set levels on interfaces on how to want to prioritise that port from lowest to highest but this does not help me if the phone and computer are sharing the same interface

i am making sure all the switches are connected to each other via the trunk ports incase we ever wanted to use the VLAN capibility but i am trying to keep away - as our network has been surveyed and we are using 5% maximum bandwidth at any one time

DSCP i do not quite understand yet - this i something like queueing of traffic and and given priority to certain packet headers? which i guess could be helpful but i am unsure if i am looking at this is the correct way?

also we have three areas on site which i was thinking of placing 3x GSM7312 in out areas with multiple in/out fibre optics around our site and i am hoping i can set all the ports as trunk ports they are really just trunk port switches to feed out to the other FS728TP's

GSM7312: from what i have read on these i can set VOIP via the diffserv wizard to do my initial setup.......

then i was wondering if i set the QoS to DSCP Enabled on the FS728TP's would these learn and use the DSCP settings set on the GSM7312???? if so my solution is found but i need a confirmation that my mind is in the correct place

also....one last question - all the priorities are done on lowest to highest - if it was set to low..is there a bandwidth limit compared to highest?

sorry for the long story - i can create diagrams or make phone calls if anyone would like to leave something in my inbox directly - if not i will contact netgear technical support to see if they could help me but i dont want to get someone that will just agree with every word i say with it should do


Cheers

CCENT, CCNA
MCP, MCSA
Comptia: Network Essentials, Security +, A+

 

[VinceWhirlwind]

The phone has a switch inside it which connects your LAN to the PC - this means the phone and your LAN switch actually use a trunk link between them, carrying the voice and PC VLANs. The PC plugs into the back of the phone, and that port is confgiured as a normal edge switchport in the data VLAN.
The people selling you the voice system should be able to explain this to you. If they can't explain it, don't buy it from them, they'll just make a mess of your network.

 

[whykap]

Let me add, the fact that you mention putting phones and pc's in the same vlan is simply bad practice. Particularly with 200 users on your network.
I suggest you do some reading on this and implement Vlans on you network to support the telephony environment your will be adding. You claim to be a CCNA so that should be within your capabilities.

I agree with Vince on the reseller comment and if they are telling you that you can put the voice on the same vlan as your data you need to kick them out now.

 

[VinceWhirlwind]

As far as QoS goes,
- your application/phone config should have QoS settings - either simply "enable", or defined as "5" or "EF" or something.
- your application/phone sets the voice packets with an IP precedence of between 0-7 for QoS. 5 is normally voice.
- your network card puts the voice packets into frames, and those frames have a DSCP field for QoS.

Routers in your network use the IP Precedence for prioritisation or bandwidth management.
Switches in your network use the DSCP tags for prioritisation.

So, make your voice gear tag packets with "5", DSCP EF.

 

[lagcat]

cheers people

i was sent a couple of trial phones out so i will test these out and test the VLAN i am looking at configuring...

we are still in a quotation phase with different systems at the moment so the techinical side is waiting until after for some reason but there are not much between either of these systems

think we are down to avaya ip500, avaya cs1000, a mitel unit which we need to find out more about and a software solution we are not keen on

but let me double check one thing you have just told me

the ports on the phone for the PC + switch connection:
if i use this method this will put the phone is the same Vlan i use for Data?? meaning i will have to have a seperate port used on the switch for my voice so it goes into the correct VLAN - so i could not use the PC port on the phone if i want to use the VLANS?

my experience is mainly with routing rather than switching as we mainly create many VPN's between companies - this is the first time i have really needed to do any switching for the last 5 years so VLANS i do not have a huge amount of experience

i have plugged a VOIP phone is already on one of these switches and could see the phone got automatically moved to a different priority compared to data for the QoS that no setting up for the phones individually looks like it is needed

if i have any questions about VLANs could someone PM me a number if they would be able to give me some advice...that would be very helpful is that ok

if not i will try and keep this thread upto date with each stage i am at

Cheers

CCENT, CCNA
MCP, MCSA
Comptia: Network Essentials, Security +, A+

 

[kwing112000]

We sell and install a lot of Avaya. I deal with the IP500. what you will want to do is set up your switch ports so they can handle more than 1 VLAN. then the phone will boot into say VLAN50 and only be used for VOIP. then your PC that is plugged into your phone will boot to the default VLAN or another VLAN if needed. you can have multiple VLANs on the same switch port.

Kevin Wing
ACSS Small and Medium Enterprise (SME) Communications
ACS- Implement IP Office
ACA- Implement IP Office
Carousel Industries

 

[lagcat]

thanks kwing can you explain how to split the traffic to different Vlans from the same port??

sorry if these are annoying questions with simple answers.....

from what i always remember with VLans is that you would set the individual ports for each Vlan and use the trunk ports to keep the VLANS between switches but both VLANs off the same port seems more tricky

Cheers

CCENT, CCNA
MCP, MCSA
Comptia: Network Essentials, Security +, A+

 

[kwing112000]

it really depends on what type of switches your using. Cisco you would make your ports trunk ports and allow the VLANs on them then set a native port, with HP you would leave the data untagged and tag the voice on each port. I dont know netgear well enough to tell on those.

Kevin Wing
ACSS Small and Medium Enterprise (SME) Communications
ACS- Implement IP Office
ACA- Implement IP Office
Carousel Industries

 

[lagcat]

yes Kwing, uses tagging aswell...i will read up on this and see how i would do it...

with port tagging...can you still tag the voice VLAN and use it with the ports ont he back of the phone??

i will read up alot more on this...the netgear information on VLANS is not very helpful so i will check the HP information and see how much i can share between to understand it completely

CCENT, CCNA
MCP, MCSA
Comptia: Network Essentials, Security +, A+

 

[VinceWhirlwind]

lagcat, you seem to have missed my prior post - the phone is a switch.

The connection from your LAN to your phone is a 802.1q trunk, carrying both phone & data VLANs, like any other inter-switch link.

The phone uses the voice VLAN - your phone config needs to identify the voice VLAN either through a DHCP option or CDP/LLDP from the switch.

The "PC" port on the back of the phone will be configured in the phone config as an edge/access/untagged port in the data VLAN.

 

[lagcat]

ahhhh thanks vince....i need to open my eyes more

i am cooking on gas now its making much more sense for the VLAN i completely forgot about the DHCP option for the phones......i only set one up the other week for a VOIP connection to Saudi over our leased line to save phone costs

Cheers

CCENT, CCNA
MCP, MCSA
Comptia: Network Essentials, Security +, A+

 

[Sympology]

Also check out you bandwidth's available. If just using LAN, go for a nice big fat G711, but if more restricted WAN, time to get that calculator and slog over your network monitoring stats.


Then head over to

http://www.bandcalc.com/

to get your stats right.

Robert Wilensky:
We've all heard that a million monkeys banging on a million typewriters will eventually reproduce the entire works of Shakespeare. Now, thanks to the Internet, we know this is not true.