Cisco SG300 Switches

Good Morning,

I currently have a setup with multiple cisco SG300 switches and ayava ip office . Currently on the first floor we have a router and two SG switches . The router is connected directly to SW 1  and then connected via another port to the SW 2 and so on. A separate DHCP server is also setup through a windows 2003 domain controller.

On the ground floor,we have the pbx connected to port 12 on switch 4  (with only the Voice Vlan tagged).Another uplink on switch 4 is connected to switch 3 and then switch 3 is connected to switch 2 via a trunk port .

ISSUES  NOTICED

The phones on the first floor are able to be up and the pc plugged directly into the back of the phone and they are able to get a data ip address and work fine. This is with each port programmed with the voice vlan as tagged and the data as untagged PVID.

The phones on the ground floor work with the same settings for a very short time after which the phones drop connection and the pc remains up. The error on the phone says no file server address or DHCP discover .

Also,from a user machine in a data vlan we are not able to browse to all the switches on the network.

Can anyone confirm of any errors I have made as well as the settings that should be on each switch port that is connected as a trunk ?

A picture is attached with the setup.
Allistair_ThomasAsked:
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arnoldCommented:
where is the windows 2003 server connected? One thing you can try is to mirror the feed port on sw4 and connect a network monitor system (laptop with wireshark or MS network monitor tool to see whether the PC broadcast is seen there. Then repeat this on sw3 to see whether the dhcpdiscover from sw4 is seen there.

I think the solution is to use an IP helper/DHCP relay agent on sw4 for the data VLAN to forward it to the server to see whether that fixes the issue.
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arnoldCommented:
Not sure I understand your layout.  Usually you would want to chain/interconnect the switches using ports 1-4 the gig ports.  Check the vlaning on the switches.

Image not attached.
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Allistair_ThomasAuthor Commented:
The switches are interconnected using ports 1-4 . I have reattached the image.
Expertsexchange-File.jpg
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arnoldCommented:
Double check that the VLANs that exist on each switch match the VLAN on your Router/PBX which is presumably the one assigning IPs.

At one interconnect between sw2 and sw3 the VLANing/trunking might not be setup or the same on sw3 to sw4 such that they ....... fall out of whack.
is the distance between sw2 and sw4 this large that sw3 needs to be in the middle?  are you able to plug a phone/system into sw3 to see if it works correctly?
Usually, the sg300 are preconfigured to VLAN based on macaddress prefix. You need to add the avaya phone MAC ( i think it is the first 6) to the default voice VLAN Tag.  If your Avaya phone is not being auto-tagged into the Voice VLAN, the Device connecting behind it might not be allowed access to the data VLAN which is likely the VLAN the Avaya Phone uses.
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Allistair_ThomasAuthor Commented:
Ok. Yes the distance between the switches is as such that switch three needs to be in the middle. What i have noticed is that for the uplink ports the voice vlans needs to be set to untagged and the other vlan (data set to tagged). With that setting,  switch 2 and 1 are able to work with the computers being  plugged into the back of the phones. The setting on each port for switch 1 and 2  is voice tagged and data untagged pvid. However, with the same setting on switches 3 and 4 , the computers  and phones do not stay configured . The configurations work for a few phones and pcs and after a while the phones say no file serv address of dhcp discover.
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arnoldCommented:
It sounds as though it is a VLAN issue which prevents the DHCP broadcasts from reaching the DHCP server. Configure DHCP agent/ip helpers on sw4 directing it to the router and see whether that resolves the issue.
Your feed from sw2 to sw3 might not be defined/set/or perceived as a trunk feed high leads to this issue,
Check the sw1 to sw2 ports settings, then match sw2 to sw3 replicating the same parameters/settings as sw1 to sw2

Ip helper no matter whether the VLAN is correct, will at least get an IP to the phone/device ........
The mismatch in vlans could also cause issues I.e. Voice VLAN traffic is prioritized, at some point they get reversed and the wrong data receives priority.........

If you could test, connect a phone and a PC on sw3 to see whether it is the source of the issue rather than sw4.  I.e. You might be looking at sw4 as the culprit while it is the victims of two or the feed from sw2.

The closer you can get to the router when the error manifests itself the closer you get to a solution.
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Allistair_ThomasAuthor Commented:
Thanks for your suggestions . I will check the ports again to confirm the settings. However, my thought is if sw2 and sw1 are ok and they are getting an ip address from the PBX connected to switch 4 then the settings should be fine.
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arnoldCommented:
Are all your phones avaya?

compare the port to which you connect the avaya phone to the vlaning of the PBX connection.

Do you have ip helpers on sw1 and sw2?
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Allistair_ThomasAuthor Commented:
All Phones are avaya. No Ip helpers on Sw1 and sw2 .
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arnoldCommented:
To your point only port 12 on sw4 has a VLAN assignment for the PBX connection.

Feed from sw1 sw2 and sw3 and everything works there only sw4 has issues.


Let me clear things up for myself the phones work everywhere, the data /PC feed through the phone is what has issues on sw4 connected phones.
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Allistair_ThomasAuthor Commented:
the data/pc feed through the phone is what has issues on phones connected to switch 3 and switch 4
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arnoldCommented:
Wht system allocates Ips to the Pcs? Is the PBX allocating both IPs to the phones and to the pcs or the PBX issues IPs to the phones and the router allocates Ips to the PCs?

Are the switch Ips on the same segment? Or the segments differ?
How are the ports interconnecting the switches VLAned, are all set to the default I think VLAN1?
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Allistair_ThomasAuthor Commented:
The phones get ip addresses from the pbx and the pcs from a DHCP server (windows 2003 with option 176 configured). All the switch ips are on the same segment . The ports  interconnecting the switches are set to untagged for the voice vlan.

I noticed that this is the only way the phones come up .
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Allistair_ThomasAuthor Commented:
Thanks , I will try some of these suggestions . The windows 2003 server is connected to switch 1.
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arnoldCommented:
so your issue starts between sw2 and sw3 if sw3 has the same issue phone/no PC
otherwise the issue is between sw3 and sw4.
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