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New Member

Cisco 2900 in Combo

Can any of Cisco 2900 router support 8 PRIs?   I need to support 8 PRIs to PBX, and also should have port available for WAN connectivity for SIP trunk.


I think Cisco 2911 can accommodate 8 PRIs, but then it won't have any slot available for WAN connectivity. 


Basically, need to know if either 2911, 2921 or 2951 will allow 8 PRIs with WAN connection.


Any help will be appreciated.





Yes all 2900 series will

Yes all 2900 series will support 8 PRI. 2901, 2911, 2921 and 2951 all have 4 EHWIC slots which can support VWIC3 cards.

2901 - will support VWIC3-2MFT-T1/E1 so you can populate all 4ehwics to get 8 PRIs.

All other 2911, 2921, 2951 will support VWIC3-4MFT-T1/E1 so you can use just 2 of these 4 port cards and have 8 PRIs.


For WAN connection (depending on what type of connection you are using) you can use integrated WAN ports (2 in 2901 and 3 in higher series router).


Hope that helps.





Just to add if you are

Just to add if you are planning to use all 8 PRI and will be using this router for WAN connectivity - based on your needs I would recommend go for a powerful router i.e 2921 or 2951 keeping in mind throughput requirements and any future possible expansion etc.


Here is the link which compares the features etc.:


You can also go through data sheets as well if you need to find any more info.



New Member

Thanks Terry!  Just to add

Thanks Terry!  Just to add that a few years ago Cisco had a serious problem with 2-Port VWIC-MFT card where if customer would connect two WAN connections on the same card, the clock source wouldn't be synchronized with ports reporting lots of errors causing issues.


I am kind of coming back to Cisco Technologies after a while so don't know if it will be ideal to connect all 4 PRIs or 2 PRIs on 2901 on the same card if the issue is still there.


Thanks again!



Hi Mate - Generally speaking

Hi Mate - Generally speaking they work good. I have lot of deployments where ISDN PRI for Voice is working fine where all the ports on a card are populated.

Again it depends on what goal you are trying to accomplish, what is your budget, capacity planning, redundancy\HA needs or your WAN throughput needs etc. that can determine which specific series you select. But to answer your question any of 2900 series will do 8 PRIs and should work without any issues if you populate all the ports on a card - that's what they are meant to do.

But having said that one more thing you will need to consider is the DSP resources required. As you might have seen from the comparison sheets 2901 and 2911 have only two PVDM slots - so you can have 2* PVDM3-256. Each card will do 256 channels for high complexity codec and 120 for low. So plan according to your needs and choose the router which suits your needs.

Please rate helpful posts and mark the thread as answered i you have no other queries.





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