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Cisco 2521 Router


I am trying to put together a home CCIE lab, would the 2521 be sufficient as a frame relay switch? Or do i need something with more ports (2522 or 2523) also, would I be able to use both the Async and Sync serial interfaces on the 2521 with my other 2500 series router? Or is it just the Async? Thanks in advance.

New Member

Re: Cisco 2521 Router

First, in order to test FR properly, you will need at least 3 serial ports to be put in FR cloud. When I had built my CCIE lab, I have used an old c4000 router with sync ports. I never tried to use Async ports for FR switching :)

Re: Cisco 2521 Router

2521 has 1 token ring, 1 isdn, 2 sync serial and 2 async/syncserial.

Well this can help you in making a frame-relay switch with four interfaces, if that is enough for you ( i think it should). Note that the 2 asyn/sync serial interface, can be clocked only upto 115kbps compared to higher speeds possible on the sync serial interfaces. Otherwise 2521 should do the job for you.

If you dont have an access server (terminal server), which helps in logging into consoles of each router in your lab - like a 2509 or 2511, I would recommend getting a 2522 router. It can serve the purpose of Access Server/ Frame-relay switch at the same time.

This is how I built such a lab for my CCIE preps..

I couldnt afford buying an access server, somehow managed to get this 2522, which had 8 low speed async./sync interface and 2 high speed sync serial interfaces. I wanted a 5 router frame-relay lab scenario for which i used the 2 sync serial interface as well as 3 async.sync interface of the 2522.

Now I have 5 remaining async/sync interfaces, which is gonna be my terminal server interface. I managed to get some db60 to rs232 cables and connected a rs232 to rj45 adapter and hooked one end of the cisco roll over console cable to the rj45 adapter and other end to the console of individual routers. The 2522 was then configured as a Terminal server. (

The 2522 is a great multipurpose router for the lab.


New Member

Re: Cisco 2521 Router


Thanks for all the info, just to get things straight. Can i connect a regular async port on a 2501 to the sync port on the 2521 for the frame relay? Or would I need a special adapter ?

Thanks again.

Re: Cisco 2521 Router

Yes you can connect them, at clock speeds not more than 115kbps. You can use the normal back to back serial cable.

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