recs/help with Switch Purchase for Office

[stim]

Hey guys,

My company is switching to VoIP phone service and I have been tasked with upgrading our infrastructure to cope. We are finally graduating from a nest of 7 WRT54G Netgear routers with DHCP disabled, and are planning on purchasing a Cisco switch to complement our "new" Cisco 7961G phones.

We will have the following items on the new switch:

- 26 PCs
- 18 Cisco 7961G phones
- 2 networked printers
- 1 network storage device (WD My Book World Ed. 750GB)
​

We will need:

- PoE
- to create 2 VLANs for two separate internet connections.
- 36+ ports
- to keep costs down
​

From talking to a few different people, it seems like the best option for us is to get 2 of the Cisco 3524-PWR-XL-EN switches.

We should be able to use the 10/100 switches in the phones to bring just 1 cat5 back to the switch for 18 of the workstations, but I would like to make sure we have space for future capacity.

Do you guys have any thoughts or recommendations for this setup? Is there a better Cisco switch combo we can use?

let me know if there are any other details I can include.


One last item that may elicit some strong opinions: I am considering doing all the initial configuration and setup by myself (no prior Cisco experience, but their documentation sure is nice...). Is this doable? If I do get someone else to configure the system, is there anything I should look/watch out for?

 

[CaseyBlackburn]

What are you wanting to do about a router?

 

[stim]

Routers are being supplied by both ISPs. Each router will handle DHCP on a separate VLAN.

 

[dashpuppy]

does this switch have QOS ? I know voip will want this to help with traffic. It sure sucks when some one on the network is copying / putting a file on that nas drive and eating up allllllll the voip bandwidth.

 

[CaseyBlackburn]

Routers are being supplied by both ISPs. Each router will handle DHCP on a separate VLAN.

Are you planning on having certain computers on certain VLANs? VOIP on one, computers on the other?

 

[dashpuppy]

Are you planning on having certain computers on certain VLANs? VOIP on one, computers on the other?

That would be ideal and QOS too.

 

[stim]

Are you planning on having certain computers on certain VLANs? VOIP on one, computers on the other?

Yes. Cisco VoIP phones on one VLAN and all data traffic over the other VLAN. The only caveat there is that I plan on using the 10/100 switch built into the 7961G phones to tie in the computer at the workstations with phones. This ties into the question from dashpuppy below...

does this switch have QOS ? I know voip will want this to help with traffic. It sure sucks when some one on the network is copying / putting a file on that nas drive and eating up allllllll the voip bandwidth.

Yes. This data sheet seems to corroborate what I was told by a few vendors.

 

[dashpuppy]

Yes. Cisco VoIP phones on one VLAN and all data traffic over the other VLAN. The only caveat there is that I plan on using the 10/100 switch built into the 7961G phones to tie in the computer at the workstations with phones. This ties into the question from dashpuppy below...



Yes. This data sheet seems to corroborate what I was told by a few vendors.

QOS will be important for you, for this to work properly. Or separate vlans one for computer/NAs. And other for voip.

 

[stim]

QOS will be important for you, for this to work properly. Or separate vlans one for computer/NAs. And other for voip.

From my conversations with a few vendors, it sounds like the switch automatically prioritizes Cisco packets (my voice packets in this case) over other traffic.

Plus, as i mentioned above, all voice traffic will be going over its own T1 and will be on its own VLAN, completely separated from any computer/NA data traffic, which will be on a separate VLAN (and going over its own 3Mb connection).

I don't even think you need to specify MAC or IP to set priorities on ports, although I'm still digging through documentation.

 

[dashpuppy]

From my conversations with a few vendors, it sounds like the switch automatically prioritizes Cisco packets (my voice packets in this case) over other traffic.

Plus, as i mentioned above, all voice traffic will be going over its own T1 and will be on its own VLAN, completely separated from any computer/NA data traffic, which will be on a separate VLAN (and going over its own 3Mb connection).

I don't even think you need to specify MAC or IP to set priorities on ports, although I'm still digging through documentation.

Probably just a feature you turn on or enable, and it does the rest.

 

[stim]

Yea. I'm starting to work through the 3500X series documentation to get a feel for how the setup and management on the switch works.

Any recs as far as configuration go? get a specialist? give it a go on my own?

 

[dashpuppy]

Yea. I'm starting to work through the 3500X series documentation to get a feel for how the setup and management on the switch works.

Any recs as far as configuration go? get a specialist? give it a go on my own?

If you are willing to learn i say go for it, there is so much help on this forum, all you have to do is ask

 

[stim]

yea, as tempting as I find it to try to crank on the configuration, I'm sure my boss will rain on my latent sysadmin dreams.

But ongoing management may end up in my domain, so I will definitely be scouring the forums.

 

[Shadowspawn]

Sample access interface configuration:

switchport access vlan XXX
Switchport mode access
Switchport voice vlan XXX
Spanning-tree portfast
Spanning-tree bpduguard enable
storm-control broadcast level 5.00
storm-control multicast level 70.00
mls qos trust device cisco-phone
auto qos voip trust

Sample router interface configuration (switch interface that feeds the routers)

switchport access vlan XXX
Switchport mode access
storm-control broadcast level 5.00
storm-control multicast level 70.00

There are additional, fancier configurations you could put in place but this should get you started.

I am assuming you are using some sort of Cisco Call Manager?

You should disable LLDP on the phones and leave CDP enabled.

The switch will recognize the phones and place their traffic on the voice VLAN automatically.

That should give you a good start.

 

[dashpuppy]

See ^^ i told you there is a lot of help on this forum!

 

[stim]

thanks a bunch, shawdowspawn.

I am assuming you are using some sort of Cisco Call Manager?

You should disable LLDP on the phones and leave CDP enabled.

We will have a hosted PBX through a different company (read: not Cisco). The service will have an AutoAttendant on their server (as well as all the other fancy hosted services), but no UC on our end as far as i know.


once i set the ip in the initial configuration, those are pretty much the next steps? Is there a way to do global config on all ports or do i have to go and do interface for each port I plan on using?

Since I am planning to have a computer and a phone on a single cat5 coming into the switch, do I need to set up those ports to trunk and split traffic to each vlan?

interface fastethernet XX/XX
switchport mode trunk

or will it just distribute based on headers without any additional config?


I will also have some workstations that will only have a computer. any special bits there? i assume those ports would just get:

interface fastethernet XX/XX
switchport mode access

Is there a reason to set one over the other VLAN as native? I guess data would be more prevalent so that would make sense as native...

sorry, lots of questions. thanks for the help.

 

[stim]

switchport access vlan XXX
Switchport mode access
storm-control broadcast level 5.00
storm-control multicast level 70.00

Are these levels pretty standard for an office environment? are they consistent with our 10/100 setup?

 

[Shadowspawn]

thanks a bunch, shawdowspawn.

We will have a hosted PBX through a different company (read: not Cisco). The service will have an AutoAttendant on their server (as well as all the other fancy hosted services), but no UC on our end as far as i know.

I am not familiar with this type of setup. Will your local DHCP server provide the IP address to the phone along with the IP address of the call manager, which is hosted by the other company? As far as I know there must be a call manager involved when using Cisco VOIP phones. A call manager and a gateway. The gateway is a router with T1 interfaces. The gateway will probably be hosted by your ISP but the call manager is usually yours...but doesn't have to be.

once i set the ip in the initial configuration, those are pretty much the next steps? Is there a way to do global config on all ports or do i have to go and do interface for each port I plan on using?

configure terminal
interface range fa0/1 - 46
...(interface commands)
exit
exit

Using the range command will allow you to give the same commands to multiple interfaces. You can even use commas to break up multiple ranges.

Since I am planning to have a computer and a phone on a single cat5 coming into the switch, do I need to set up those ports to trunk and split traffic to each vlan?

interface fastethernet XX/XX
switchport mode trunk

or will it just distribute based on headers without any additional config?

As long as you are using Cisco phones that the switch will recognize using CDP you can use the configuration I showed you. You only need to use trunk statements if you are using other makes of phones that don't support CDP.

I will also have some workstations that will only have a computer. any special bits there? i assume those ports would just get:

interface fastethernet XX/XX
switchport mode access

Leave all of the access interfaces the same. This way, when equipment is moved around, you can plug and play and the switch configuration is one less issue to worry about. If a phone is not detected on the interface the voice VLAN simply won't be used.

Is there a reason to set one over the other VLAN as native? I guess data would be more prevalent so that would make sense as native...

I'm not sure which configuration you're asking about here. From your initial post I understood you to have one ISP for voice and one ISP for data. So you would use the appropriate VLAN when connecting to those ISP routers. A trunk is not needed for those interfaces because you are only passing one VLAN. If you are passing another VLAN, perhaps for management, then I suggest you create a third, dedicated, trunking VLAN for those links.

BTW, if you end up with multiple switches, you will need a trunk between them. The configuration would look something like this:

switchport trunk encapsulation dot1q
 switchport trunk native vlan 999
 switchport mode trunk

In my example, VLAN 999, is a dedicated "native_trunk_vlan". It isn't used anywhere else except for the trunk interfaces. This is just good practice.

sorry, lots of questions. thanks for the help.

No problem. If I didn't want to help I would have just skipped to the next thread.

Are these levels pretty standard for an office environment? are they consistent with our 10/100 setup?

I don't know that Cisco recommends a particular level. They are percentages, so if you have 5Mb of broadcast traffic something is wrong. These are what we put in place, thinking we would adjust as needed but we never needed to adjust them.

 

[dandragonrage]

You want to keep costs down, but you want a Cisco switch?

Make sure your PCs with Realtek NICs are only connected to a switch made with Realtek chips, Broadcom NICs only connected to a switch using Broadcom chips, etc., then. Ah, the logic of business... it never makes sense.

 

[stim]

You want to keep costs down, but you want a Cisco switch?

Make sure your PCs with Realtek NICs are only connected to a switch made with Realtek chips, Broadcom NICs only connected to a switch using Broadcom chips, etc., then. Ah, the logic of business... it never makes sense.

Haha. Fair, dan. Brand/Brand matching seems to be gospel.

At least as far as cost, these switches are dirt cheap, especially compared to the ones that are actually currently supported by Cisco.

 

[stim]

I am not familiar with this type of setup. Will your local DHCP server provide the IP address to the phone along with the IP address of the call manager, which is hosted by the other company? As far as I know there must be a call manager involved when using Cisco VOIP phones. A call manager and a gateway. The gateway is a router with T1 interfaces. The gateway will probably be hosted by your ISP but the call manager is usually yours...but doesn't have to be.

I'll check with the new voip provider to see what the Call Manager situation is. I wonder if their hosted software replaces it? From what I understand, all voicemail, call routing, AutoAttendant, FindMe/FollowMe takes place on their servers.

As long as you are using Cisco phones that the switch will recognize using CDP you can use the configuration I showed you. You only need to use trunk statements if you are using other makes of phones that don't support CDP.

so i can use the syntax you gave, but I still need to create a separate VLAN for voice, right?

vlan server
vlan 2 name vlan_voice
exit

I feel like I've seen a few sites that say, while the switch will separate voice and data packets, it is better to just create a separate VLAN instead of relying on the logical separation.

I'm not sure which configuration you're asking about here. From your initial post I understood you to have one ISP for voice and one ISP for data. So you would use the appropriate VLAN when connecting to those ISP routers. A trunk is not needed for those interfaces because you are only passing one VLAN. If you are passing another VLAN, perhaps for management, then I suggest you create a third, dedicated, trunking VLAN for those links.

What do you mean by "passing 1 vlan"? So since the phone and computers doesn't need to access eachother's vlans, there's no need to trunk?

BTW, if you end up with multiple switches, you will need a trunk between them. The configuration would look something like this:

switchport trunk encapsulation dot1q
 switchport trunk native vlan 999
 switchport mode trunk

In my example, VLAN 999, is a dedicated "native_trunk_vlan". It isn't used anywhere else except for the trunk interfaces. This is just good practice.

Is VLAN 999 pre-set? or do I need to create it?
What is the mod/port designation for the Gb ports on the 3524?

so the full syntax for both Gb ports would be?:

configure terminal
interface gigabitethernet XX/XX
switchport trunk encapsulation dot1q
switchport trunk native vlan 999
switchport mode trunk
end

I don't know that Cisco recommends a particular level. They are percentages, so if you have 5Mb of broadcast traffic something is wrong. These are what we put in place, thinking we would adjust as needed but we never needed to adjust them.

I should probably read up on broadcast vs. multicast traffic...

Thanks again, and feel free to split up responses into posts. maybe that would help track different questions.

 

[stim]

Here are a few other minor config questions:

Do I need to specify port speed and duplex parameters? A few vendors have said that having speed set to auto is a potential issue. I assume full duplex is fine for both voice/data and data ports.

Is there anything specific I need to do for the ports that will have the incoming wire from the two routers?

Should I turn PoE off for ports that do not have phones?

 

[Captain Colonoscopy]

You do realize that Cisco 3524XL-PWR switches are no longer supported by Cisco right? Also, there is no automatic QoS on those guys, you have to configure everything manually, make your own policies, assign to switch ports. I would highly recommend getting a newer 2960 series switch with PoE. You'll thank yourself later.

 

[stim]

You do realize that Cisco 3524XL-PWR switches are no longer supported by Cisco right? ..... I would highly recommend getting a newer 2960 series switch with PoE. You'll thank yourself later.

Yea i realize they are 10+ years old. Cost is a big roadblock for us, but, if we can justify dropping more cash we could move up.

I'll look at the 2960 series to see what's available. any other series that are still supported but may be more affordable? we would also be fine with a single 48-port as well...

Also, there is no automatic QoS on those guys, you have to configure everything manually, make your own policies, assign to switch ports.

so the auto qos voip trust language doesn't work on the 3524?

I would need to set CoS on each vlan then?

 

[stim]

Hi guys,

sorry for the delay but i just wanted to say thank you for the discussion and comments.

we ended up with a cisco 3560 48-port switch and found a solid local dude to program it up for us.

i will be looking over his shoulder more as we repro it for the dual internet connection and am looking forward to checking out all that we have discussed here.

thanks again!