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I have a Cisco 2901 at a remote branch office connected via ge0/1 to an Adtran that is managed by TW Telecom with 8 T1s bundled together for an MPLS circuit.

I don't have access to the Adtran gear, it belongs and is serviced by TW.

At times we've had a T1 go down in the bundle and TW will open a proactive ticket for it.

However, is there any way for me to (from the 2901):

  1. know that a T1 is having issues or is down in the bundle? (obviously if they all go down I'll know it, since I won't be passing traffic.)
  2. Determine actual bandwidth available from the 2901 or some other way to tell if the entire bundle is up or not.

Short of having someone in the remote site go to the smart jack and say "yes they are all showing green" I'd like some way to monitor in addition to relying on TW if possible.

TheCleaner
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  • what model of "adtran"? (they make a lot of stuff) – Ricky Jun 07 '13 at 20:19
  • IP SLA comes to mind, but it won't be accurate enough to determine if one of eight (1/8) links went down, especially since the overall link utilization fluctuates. – Yosef Gunsburg Jun 07 '13 at 20:26
  • @RickyBeam - sorry I believe it is a Netvanta 4430. – TheCleaner Jun 07 '13 at 20:30
  • Oh, just for discussion sake, I will argue that if this were a Sprint circuit, their "Compass" tool would be enough for me. TW's customer portal is horrible compared to Compass. – TheCleaner Jun 10 '13 at 13:03

3 Answers3

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You could ask TW to give you SNMP read-ony access to the box if possible

mellowd
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The short answer is "no". Without visibility into the status of the T1s, you have no way of knowing if one is down (in alarm) vs. just not passing traffic (unbundled). TW will have to give you access to the system (telnet, snmp, etc.), or setup a means of notifying you of status changes (syslog, snmp trap, etc.)

Ricky
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Fully agreed with @ricky no way today, there isn't any signalling protocol which allows transferring information of L2 protocolX signalling to L2 protocolY, maybe there should be. But even if such protocol would be specified, I don't really expect T1 people would invests on new gear to get it.

Personally I don't understand why connections are build like this. Some business people claim that customer damand RJ45 ethernet interface, so for some customer even when fibre gige connection is delivered, there is optical converter (Another SPOF which customer cannot monitor!).
I would throw the adtran out of the window and buy T1 interface to the 2901. This has several benefits

  1. One less SPOF
  2. Link-state is reliably exchanged, so you can converge
  3. You get all signalling data for much more rapid troubleshooting
  4. Your QoS actually works, as shaper knows true rate and overhead
ytti
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  • Sounds to me like they have multiple T1s tied together with a mux, the link aggregation of the T1 world. I don't believe the T1 interface provides this capability. – YLearn Jun 08 '13 at 13:50
  • Without knowing specifics hard to consider options. But they might be multilink PPP (also helps with serialization delay as you can fragment packet to each link), ECMP or chSTM1 and more channels. – ytti Jun 08 '13 at 13:56
  • True, but it was mentioned that there were 8 T1s bundled together as one circuit. Tie in the problem described and I would bet on a mux. – YLearn Jun 08 '13 at 14:11
  • @Ylearn In my experience with Adtran Netvantas, they're likely using PPP Multilink to bundle the T1's. I've worked at an ISP who used them as PE equipment for this very purpose. – Brett Lykins Jun 10 '13 at 01:11
  • That's why I _asked_. The 4430 is not a mux; it's a router (with an annoying stateful firewall.) I don't know how TW set it up, but I'd do MLPPP. Larscom Mega-T, that's a MUX. – Ricky Jun 10 '13 at 06:35
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    Folks, yeah it's mlppp, with 8 T1s. I'd have to have my own router capable of having 8 T1 PIMs to get rid of their managed router. Unfortunately fiber isn't offered at this location. Thanks for all the help though...my initial thought was correct but glad I got confirmation. – TheCleaner Jun 10 '13 at 13:02
  • @BrettLykins, you are correct, I missed the comment update that mentioned the platform. I guess I lost that bet, buy you a beer if we ever meet? – YLearn Jun 10 '13 at 14:01
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    @TheCleaner This is where I might be mistaken, but I would think you could terminate the T1's into a Cisco 2901; it has 4 HWIC slots. Each slot could take one VWIC2-2MFT-T1/E1 Card, for example, and you could terminate the 8 T1's directly on the 2901. (I've done this before on a 2921, but I don't know off-hand if the 2901 could handle it.) – Brett Lykins Jun 10 '13 at 20:08