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New Member

IMA - need a little on-line tutorial

I have a customer wanting to connect to as many as 5-8 branch offices via T1 leased line. Looks like his needs are data only and I don't expect this to change. Is IMA a good alternative to multiple T1/CSU interfaces on my core (3640??) router.

If so can I get a description of the nut/bolts. I'm assuming the telco will povide up to to 8 T1 handoffs that connect to the IMA interface. From there I can configure individual serial (ATM?) interfaces for the various branch offices?



  • Other Network Infrastructure Subjects

Re: IMA - need a little on-line tutorial

why not frame relay and just map multiple pvcs onto one access link ?

what are the branch bandwidth requirements ?

New Member

Re: IMA - need a little on-line tutorial

He's running frame to 4 branch offices at present, but insists on going to full T1 leased line for each and possibly 2 or 3 more. Says his carrier is offering a deal he cannot pass up.

I know the 3640 can handle several T1s, but it's either NM-2W and WIC-2T with external CSU (ugly!) or NM-2W and WIC-1DSU-T1s - and lots of those.

I was thinking the IMA would save some slots for the future.


New Member

Re: IMA - need a little on-line tutorial


IMA stands for (inverse multiplexing over ATM) so the interfaces can only

talk ATM. Therefore your customer need to connect to an ATM Interface

on the opposite site.

Because the customer has already 4 locations connected to Frame Relay

he should either use FR-ATM internetworking or compete switch to ATM.

The advantage of using FR-ATM internetworking is that the cust must normaly

not switch the hardware at the branch offices and the main location can scale

up to 8 x T1 Mbps with a 8 port T1-IMA interface.

FR/ ATM Internetworking is offered for example by British Telecom in many



Ulrich Marzoli

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