Bonded T1s

[skhirbash]

Hi all,

I would like to know how to configure a single T1 DSU/CSU connecting to a single circut but the service provider is provisioning 2 T1/bonded ckts?

Thanks in advance,

sK

[skhirbash]

Hi John,

In the BW statement under outbound interface, what should be the BW configured for a bonded 2 T1s?

Thanks,

sK

[skhirbash]

Hi John,

In the BW statement under outbound interface, what should be the BW configured for a bonded 2 T1s?

Thanks,

sK

[John Blakley]

If you only have the one connection coming in, you can do 3088 (1544*2). The only this does though is to provide a calculation with certain routing protocols and bandwidth measurements. It won't control speed, so if they're really only pushing 1 T (1.5Mbps), then you won't see 3MB even if you set it on the interface. Does that make sense?

John

[skhirbash]

Yes, it makes sense; however, they are promising 2xT1 (bonded CKTs)but with only a single cable which will be connected to the CSU/DSU! Now, will be receiving 3088 or 1.54Mbps, that will be put to the test once the ckt is up. So, you I will configure the interface with 3088.

Thanks again John,

sK

[skhirbash]

Yes, it makes sense; however, they are promising 2xT1 (bonded CKTs)but with only a single cable which will be connected to the CSU/DSU! Now, will be receiving 3088 or 1.54Mbps, that will be put to the test once the ckt is up. So, you I will configure the interface with 3088.

Thanks again John,

sK

[paolo bevilacqua]

No, that does not makes sense, because it is impossible to give a 3mbps service using a single T1 interface that only runs at 1.5 mbps.

And you cannot "configure the interface with 3088".

So, either they will give you a enthernet interface, or two physical T1 interfaces.

[John Blakley]

impossible to give a 3mbps service using a single T1 interface that only runs at 1.5 mbps.

Agreed. But when the OP said "bonded T1s" that's how this thread got started.

I disagree on your second statement. Yes you can: (It's just for calculations)

interface Serial1/0

bandwidth 3088

no ip address

end

will give you a enthernet interface, or two physical T1 interfaces.

Ethernet possibly. Maybe they'll receive a device that bonds the two at their location and they'll connect to a switch from their router which is highly possible. I think the provider should step in and tell them exactly what needs to be done though. Seems that there's a lot of "in the air" stuff from AT&T.

John

[jgreenwoodii]

Technically is would be 3072, But I'm pretty sure it's managed based on the email from AT&T. He will use the Ethernet port on his router and set the proper IP/Mask and Default GW. Very simple setup. He may have to run the Ethernet cable from the Demarc to connect the circuit into AT&T router if they don't go out there to physically set it up.

HTH

Jonathan

[paolo bevilacqua]

I disagree on your second statement. Yes you can: (It's just for calculations)

interface Serial1/0

bandwidth 3088

no ip address

If you do this:

1. the physical behavior or spred of the interface will NOT change.

2. anything based on interface speed, as simple as an smnp graph will be wrong.

So, don't change bandwidth parameter to thing different from reality.

[Patrick Laidlaw]

So is this csu/dsu being provided and are you useing a Wic-1t or are you using a WIC-T1-DSU? If your using a wic-1t its conceivable that you would be able to get a higher bandwidth than 1.544.

[skhirbash]

Thanks for the response. I didn't know there was a difference btwn the two WICs since T1 data rate is known to provide 1.54Mbps. Are there any docs to show the difference?

Thanks, SK

[paolo bevilacqua]

There is no difference. The presence of a internal or external DSU does NOT change the circuit speed of 1544 kpbs, of which 1536 are available to hdlc / ip.

[skhirbash]

Yes, it makes sense; however, they are promising 2xT1 (bonded CKTs)but with only a single cable which will be connected to the CSU/DSU! Now, will be receiving 3088 or 1.54Mbps, that will be put to the test once the ckt is up. So, you I will configure the interface with 3088.

Thanks again John,

sK

[jgreenwoodii]

Sounds like it will be a managed service. Meaning they will place an Cisco 1841 router at your location to terminate the circuits and handoff to you on a LAN port. That's what I take from the Single Cable deal. Can you verify if they are providing a router or not to terminate the circuits?

HTH

Jonathan

[skhirbash]

Hi Jonathan,

No, this will not be a managed service. We have our own 2851 router with a new T1/CSU-DSU module that I installed last week.

Here is a snapshot of thread of emails btwn me and at&t rep:

From: at&t rep

To: Me

Correct. The only thing you will have to do, concerning the equipment, is make sure the modem, router, and circuit are connected properly and powered on.

-------------------------------

From: Me

To: at&t rep

Subject: RE: AT&T: Customer Advisory Letter: Ready for Test & Turn up

I am assuming that the bonding of the T1s is done on your end but not on our end, meaning, if there is only one physical ckt (single cable) being provided and we are plugging this single cable into a single T1 DSU/CSU module, we aren't doing any bonding on our end. Would this be accurate?

Thanks in advance,

sK