IPoverATM in a PVC environment

[pohcheng]

Hi,

I refer to the following :

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http://www.cisco.com/univercd/cc/td/doc/product/atm/c8540/12_1/pereg_1/quick

_cg/arm.htm#xtocid203518

"Configuring Classical IP over ATM in a PVC Environment"

"Step 5"

"Note: The VPI number on the ATM router module interface must be 2"

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Why is there such a limitation : "The VPI number ... must be 2" ?

If my deployment require the VPI to be "0" or other values, what should i do?

Pls kindly advise asap. Thanks.

Rgds.

[pohcheng]

hi,

On second thought, perhaps the "vpi must be 2" limitation isn't that critical. Since the limitation is on the ATM router and not on the line interface, it means that i can use any vpi values on the line interface when configuring IP-over-ATM, right?

To ensure that i fully understand the limitation, would appreciate if anyone could verify the following for me.

Suppose given the following requirements:

1) my device is directly connected to the C8510 via a E1 link

2) the E1 port used is in slot#4, PAM#0, PORT#0

3) configure IP over ATM on the E1 link on VPI=0 and VCI=50.

4) the ATM router module is in slot#3

Are the following configurations steps correct?

---

Switch> enable

Switch# configure terminal

Switch(config)# interface atm 4/0/0

Switch(config-if)# atm pvc 10 50 interface atm 0 0 any-vci

Switch(config-if)# end

---

Switch> enable

Switch# configure terminal

Switch(config)# interface atm 3/0/0

Switch(config-if)# ip address 11.11.11.11 255.255.255.0

Switch(config-if)# atm pvc 2 100 interface atm 4/0/0 0 50 encap aal5snap inarp 10

Switch(config-if)# end

---

Thanks.

Rgds.

[davidreta]

0 is just a standard. You should be able to use anything in the ranges as long as your paths are consistent. A UNI header is is 8 bits giving you a range of 0-255, A NNI header is 12 bits and will give you a range of 0-4095. I hope this helps.

[oallenov]

VPI 2 is localy significant VPI number to ARM.

As you probably noticed in the config, VPI 2 is connected to VPI 50 when coming out off physical interface:

atm pvc 2 100 interface atm 0/0/0 50 100 encap aal5snap inarp 10.

So for you real connection you can use any VPI you like.

For logical connection to ARM inside your 8540 you have to use assigned VPI numbers that ARM supports.