frame and cell mode

[ciscoforum]

MPLS has two types label method. Frame mode and cell mode. ATM can be either frame mode or cell mode according to the doc. How do I know the ATM is configured as frame or cell mode. Is there a default thing? thanks

[Harold Ritter]

Cell mode was defined for ATM and is the only mode supported by ATM switches.

That being said, MPLS frame mode can be configured over an ATM PVC, in which case your ATM network doesn't even need to be MPLS aware.

Hope this helps,

[ciscoforum]

Hi Harold

Thanks.

Here is the configuration from our customer. 1.Could you tell me is this frame or cell mode?

2.Quoting what you said "in which case your ATM network doesn't even need to be MPLS aware". Is this MPLS aware or not? How to understand this?

interface ATM2/0/0.11 point-to-point

ip address 100.1.73.53 255.255.255.252

ip ospf network point-to-point

tag-switching ip

pvc 73/1052

[Harold Ritter]

This is frame mode. In this case the ATM network doesn't need to be MPLS aware. It just transports MPLS as it would transport any other protocol, such as IPv4, IPv6 or IPX for that matter.

Hope this helps,

[ciscoforum]

Thanks. Do you happen to have a configuration about to use cell mode for ATM? I want to see the configuration difference that may help me understand it better,

[Harold Ritter]

Here's an example. Bear in mind that there in not too many MPLS cell mode networks still around these days.

http://www.cisco.com/en/US/tech/tk436/tk798/technologies_configuration_example09186a0080104a94.shtml

Hope this helps,

[Harold Ritter]

Here's another that might be more useful.

http://www.cisco.com/en/US/tech/tk436/tk798/technologies_tech_note09186a0080093d41.shtml

Hope this helps,

[ciscoforum]

Thanks a lot

[sasif]

Just add two things to determine quickly if the network is Cell or frame mode:

1. When you see the tag-switching in front of the ATM interface

2. When the Labels are VPI/VCI