Cisco 2901 router can i use Ethernet Switch rather then Ethernet Routed-Port for ITSP SIP Connectivity

[anilkumar.cisco]

Hello Team,

I have existing 2901 router.. where both gig interface of the router has been consumed.. Now customer is looking for upgrading there existing E1 PRI connection to SIP.. but we don't have spare interface.. but in stock i have EHWIC-4ESG ( as per data sheet it is Ethernet switch).. not ethernet router port...

My question is whether i can use it or not for ITSP connection.. if yes.. then how?

[Leo Laohoo]

The router has two routed ports: One for LAN and one for WAN.
Why can't SIP traffic go out via the WAN port?

[anilkumar.cisco]

Hello Leo,
thanks for your reply.. as stated.. both ports are already consumed for connectivity to the customer network..
Now I am looking for some alternative option.. but right now in my stock i have only EHWIC-4ESG.. so thought to check, if I can use it for this purpose or not? thanks

[Leo Laohoo]

I can't answer your question because you're not telling us what those two ports are? Are the ports currently being used for WAN or LAN?

[anilkumar.cisco]

for LAN.. both ports we are using..

[Leo Laohoo]

So, currently, the router has two Layer 3 ports and you're using it for LAN?
And how is the router meant to contact the SIP server if the EHWIC-4ESG is a plain 4-port Layer 2 switch?

[anilkumar.cisco]

Yes.. one is primary LAN interface and another is secondary of Primary LAN interface..

[Leo Laohoo]

Is the SIP provider internal network or external?

[anilkumar.cisco]

External only.. Do we have SIP provider which provide in internal network..

[Leo Laohoo]

If the SIP provider is external, how are you planning to send SIP traffic to an external destination?

[anilkumar.cisco]

if any of the gig port would have free. then I would have connected external ITSP SIP IP address into my gig port and have done static routing toward that..

But now, I don't have free L3 interface.. but have Ether Switch module.. so thinking to swap the Gig port from physical port to ether switch module port.. create Vlan in router and connect locally there.. after then my gig port will become free and then connect SIP trunk interface to gig port and do the routing there.. do let me know if my plan is ok.. or do you have some alternative..

[Leo Laohoo]

Connect the SIP server to a switch.
Switch connects to a router.
Router has a Layer 3 port out to the net.
SIP server connects to the SIP provider via the Layer 3 port.
Phones connect to the SIP server.

[anilkumar.cisco]

Leo suggestion :-Connect the SIP server to a switch. Anil question: which switch you are talking.. I have plan to insert EHWIC-4ESG card into router to provide switch capability/
Leo suggestion :-Switch connects to a router. Anil question:- I understood inserting of the card into router.
Leo suggestion:- Router has a Layer 3 port out to the net. Anil question, which L3 port you are talking and both gig interface is already used ?
Leo suggestion:- SIP server connects to the SIP provider via the Layer 3 port. Anil question, Not able to understand as above concept is not clear
Leo suggestion:- Phones connect to the SIP server. Anil question: same as above..
Hello Leo,
I appreciate your support here..
I have issue only with design.. if any of the gig port would have been free then there would be no issue.. but the problem is no gig port is free here..

[Leo Laohoo]

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@anilkumar.cisco wrote:
which switch you are talking.. I have plan to insert EHWIC-4ESG card into router to provide switch capability

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EHWIC-4ESG is a Layer 2 switch. 

[anilkumar.cisco]

so what is your view here..

shall I request the customer to provide L3 swtich and terminate ITSP SIP link their ?? ... that design will work?? or would request the customer to purchasing L3(routed) Ether switch module is the only option..