T3 config with multiple T1s

[johnbellucci]

we are getting a DS3 without BGP for Internet to a clear channel T3 card in a 3845, with 1 GE to our LAN, 2 dual MFT1 cards to connect to 4 partner sites.

the ISP config info refers to c-bit parity (as in clear channel on ATM ?), but ATM scrambling and ATM cell mapping to PLCP with frame rely RFC2427 and ANSI LMI notes. so far, we have these config bits:

controller T1 1/0/1 (four times)

framing esf

linecode b8zs

!

controller T3 2/0

framing c-bit

clock source line

cablelength 224

!

interface Serial2/0

no ip address

dsu bandwidth 44210

scramble

no cdp enable

encap frame-relay ietf

frame-relay lmi-type ansi

how do we set ATM plcp ? are we missing some info. or config here? also, how should we safely route the T1s and the LAN GE to the T3?

thanks,

jb

[Georg Pauwen]

Hello,

you can use the command ´atm framing´ to configure the framing format. Check this document for a matrix of hardware and framing compatibility (scroll down to ´Framing Choices on Cisco Interfaces´:

Framing Formats on ATM DS-3 and E3 Interfaces

http://www.cisco.com/en/US/tech/tk39/tk49/technologies_tech_note09186a0080093c89.shtml#topic1

HTH,

GP

[johnbellucci]

thanks gp for your prompt feedback

well, we got a clear-channel NM-1T3/E3 module as the ISP suggested, so it is not an ATM DS3 module. I read the article you mention, but there are no ATM controllers present, and no available command starting with atm in any config. we hoped to get this resolved before our consultant comes back.

even with the current frame settings with lmi, don't we need some DLCI info ? do we need sub-interfaces?

thanks,

jb

[Georg Pauwen]

Hello,

inverse arp should do the job, without the need to configure any DLCIs (although inarp is supposedly not really best practice).

I am not really clear on what you are running into: is the interface not coming up, or/and do you not get any connectivity to your remote sites ?

Regards,

GP

[johnbellucci]

we don't have the circuit yet, just getting ready for it. the telco's sheet refers to ds3 c-bit coding, ATM scrambling, ATM PLCP mapping, Frame relay IETF and ANSI lmi. no mention of inverse arp, DLCIs, VCs or T3 mdl.

does anyone have a sample of T3 config for dedicated internet through MCI?

thanks

jb

[johnbellucci]

well, found out from the telco that the instruction sheet was wrong. they didn't have a sample config for Cisco, but it's a basic hdlc or ppp serial link at customer's choice.

no ATM or frame at all!

they also got the assigned IP wrong after talking with two different online techs, so now we have to wait a few more days to set it up.

anyway, thanks for the feedback!

i guess it's always good to double check with the telco a few times before wasting your time trying to troubleshoot a non-existing problem.

jb