need some help RE: VLAN/Routing

Unanswered Question
Feb 26th, 2008

Hi folks:

I ordered a Catalyst Express 500 (WS-CE500-24LC) for a branch office we are putting in our 1st VOIP phones for. We'll have about 4 phones, 10-15 workstations.

We've ordered a Split T1 (PRI 6 channels, Internet access 18). This will be an ethernet hand off from an Adtran CSU/DSU (not sure what model. the pri/split T hasn't been put in yet).

We have a PIX 501e we want to use in the branch office to potentially be our router, IPSEC VPN device back to the corporate office.

Anyways, I'll spare my colorful comments about my disappointments with the Catalyst Express so as to not make this about my distaste for this device.

I configured two VLANs in the Catalyst Express (one is the Cisco-Voice VLAN as the documentation provides). The other is just the default VLAN ID 1.

Some of my questions are:

i cn't seem to find DHCP Relay options in the Catalyst 500 anywhere. I'd like to pass DHCP requests for all vlans to a central DHCP server, but can't seem to find any DHCP forwarding/relay options.

Second, i've not touched a pix501 in ages and understand the device has been deprecated into the annals of history. but i wanted to get this device to create an IPSEC VPN back to the corporate office AND to act as a basic router for Inter-VLAN routing at the branch office. It seems as if the inside ETH0 cannot have multiple IP's assigned to it. So that's my next question. If I cannot use the PIX501 to do intervlan routing, what is a recommended router that could do the job for us.

I'm not an expert, so let me throw that out there.

I really appreciate any help.

I have this problem too.
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Edison Ortiz Tue, 02/26/2008 - 19:53

In order to forward DHCP requests from client towards the DHCP server, you need to configure the ip helper-address command on the interface facing the client subnet.

As the Catalyst 500 is only a layer2 switch, that feature is not available.

I've seen reports on that feature working on 2960 switches and they are layer2, however it's not a supported configuration.

As for the PIX501, I'm sorry to tell you it can't function as a router. It's strictly a firewall.

For your environment, I suggest purchasing a 3560 switch in order to perform inter-vlan routing.




bubbawny69 Tue, 02/26/2008 - 20:33

thanks, Edison. I'm grateful for the reply.

I guess I got wrapped up in the marketing slicks of the catalyst express series as a perfect SMB / branch office product for our needs.

I had worked with 2960's before and 3560's before and wanted to put in a 3560 (layer2/layer3) device in my branch offices originally, but it's so cost prohibitive (I work for a non-profit). Unfortunately, low up front costs for the 500 series means higher back end costs for routing, firewall. So maybe if i add the costs of a 500 switch, poe, basic router, perhaps it comes out to the starting price of a 3560.

i seem to recall working on a layer 2 switch that would push DHCP requests through from a vlan to a DHCP server. don't really remember what model it was. I've worked with Procurve and Cisco Switches (2950/60, 3560). i like the 3560.

but i needed only 4 POE ports and < 20 other desktop ports for my branch office. but in order to utilize the Cisco-Voice VLAN (required to get the QOS/COS SmartPort use), additional products are needed. And while I should have known better, it seems like the preconfigured smartports are for "cisco only" ip phones. We're putting innew Inter-tel IP phones. i'm sure i'm going to run into QOS/COS configuration issues between my IP handsets and this switch.

maybe i'll pickup a 2600 off ebay for now and pick a different, more robust device in the future for other branch office L2/L3 equipment needs.

i have a 3560 - 48 port gig switch at my corporate office doign layer 2 / layer 3 work as a core switch and inter-vlan router.

well i'm just rambling. i feel like an idiot for buying the 500 and wish i could get my money back to apply for teh 24 port 3560 i originally was going to buy. classic case of trying to get mileage from an SMB product.

i'm still kind of stunned that in 2008, layer 2/3 switches are still a premium $ as is POE. i would have thought they'd have commiditized now that IP phones are outselling traditional key phones.

spending $6k+ for a 24 port l2/l3 switch with4 poe ports seems like quite the premium for basic branch office switching/routing for IP phones.

sorry for rambling, guys. for the first time in a while, i regret my spending choice on the cisco product i chose. i should have gone with my gut and paid for the 3560.


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