UC520 data network using SR520 network

Unanswered Question
Jul 19th, 2009

Hi there,

we have a UC520 behind an SR520 router. The SR520 functions as a DHCP server.

We would like the data network on the UC520 (so, on the PC ports of the phones basically) to be directly connected to the same subnet that the SR520 is on.


SR520 has IP address and functions as a DHCP server

UC520 has IP address

We have some pc's attached to the PC port of the phones. They now get a 192.168.10.x address through the UC520. We'd like them to get addresses from the SR520.

Is there an easy way to do this or should I just create a TAC for this?


I have this problem too.
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Marcos Hernandez Mon, 07/20/2009 - 20:27

The scenario you describe is not possible, at least not if you want the UC500 to route between the two interfaces (LAN to WAN). By definition, a router cannot have two interfaces in the same IP subnet.

There are a few other scenarios that might get close to what you want, but they would be overly complicated.



eljakimit Mon, 07/20/2009 - 23:31

Hi Marcos,

but I don't want the UC500 to route. I want the UC500 to bridge. And I know that is possible since

we do it with other appliances as well.

Would you like me to explain further or should I just open a TAC?


Steven Smith Tue, 07/21/2009 - 08:25

The way to do this would to be plugging the LAN interface on the UC500 into the SR520 LAN.  You would need to setup the default route on the UC500 to point to the SR520.  On the SR520, you would need route the voice vlan to the UC520 data interface, same for the CUE subnet.  You should also delete the firewall and NAT on the UC500.  Once the changes are made, I am not sure CCA will work for you anymore.


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