Atm Switch and Frame Relay Switch

[sawquecisco]

Hi

I know the differences between frame relay and atm. Atm uses a fixed-length packet where Frame Relay uses variable length packets.

But; What is the differences between frame relay switch and atm switch?  Why does Cisco use same icon for both of them?

[Peter Paluch · Accepted solution]

Hello,

ATM and Frame Relay switches are really two very different devices because these technologies themselves differ considerably. Although their basic principle is similar: to have a table consisting of four columns:

and to switch frames (or cells) according to entries in this table, rewriting the "labels" (DLCIs or VPI/VCI values) in the process, the similarity ends here. Both technologies use different physical layers, different frame/cell format, different signalization schemes, different frame/cell scheduling, different approach to QoS and resource reservation, even different addressing - while Frame Relay is really only a Layer2 technology that does not care about network-wide addressing, the ATM was designed as an all-encompassing technology including end station addressing, in essence being a complete networking technology.

So the differences are very fundamental. The fact that the Cisco icon is identical for both ATM and FR switch is probably just a matter of convenience - don't try to find any deeper technical reason behind it. At least I do not know of any

Best regards,

Peter