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Atm Switch and Frame Relay Switch

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?

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Cisco Employee

Atm Switch and Frame Relay Switch

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

1 REPLY
Cisco Employee

Atm Switch and Frame Relay Switch

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

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