2821 router maximum T1s

Answered Question
Aug 9th, 2007
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I have a 2821 set up as a WAN router to the Internet. It currently has four T1 lines and I need to add more. What sub assembly do I need to buy to slot in more T1 WIC cards? And what is the maximum number of T1 lines I can support on the 2821 before going to another router?

Correct Answer by wochanda about 9 years 10 months ago

Sure does.

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Overall Rating: 5 (3 ratings)
wochanda Thu, 08/09/2007 - 10:05
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The most T1 ports you can get into a 2821 is 8. Since you have 4 WIC slots, you can stick a VWIC-2MFT-T1 or VWIC2-2MFT-T1 in each for a total of 8 ports.

There used to be NM adapters for adding WIC slots, but I don't think they're supported any more in the 2800 series.

rapassano Thu, 08/09/2007 - 11:21
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Thanks! I did get a part number for a dual T1/E1/PRI card for the Network Module slot -

NM-2CE1T1-PRI - but am not sure if that will work in the 2821 with the multilink group configuration we intend to use on the six T1 lines. Would that work or are the VWIC cards a better choice here?

wochanda Thu, 08/09/2007 - 11:57
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Yup, thats the one. It looks like it is supported in the 2821. It doesn't look like you gain anything from using this module over the VWIC, except maybe ISDN functionality.

The VWIC would take up less space in the chassis, so you'd still have your NM slots available for ESW (ethernet switch) modules. It may just come down to price, though.

rapassano Thu, 08/09/2007 - 14:08
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Maybe more detail would help. We already have four WIC-1DSU-T1-V2 cards in each 2821. Ideally I would like something simple, like a NM-2W network module that would accept two of the same type T1 cards already in use. This network module shows as being supported in the 2600, 3600, 3700 and 3800 series routers but unfortunately not the 2821....darn! Since replacing all existing WIC cards with VWICs is likely way more expensive I am thinking that the 2 port E1/T1/Pri network module is the best choice. Hey, it does have an internal DSU, right?

Correct Answer
wochanda Thu, 08/09/2007 - 19:21
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Sure does.

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