T1 Bandwidth Question

ITtech2010

Hi All,

I had a question regarding T1 bandwidth. At my job we subscribe to multicast from Nasdaq through our provider BT Radianz. By November 17th Nasdaq will publish new multicast services. BT Radianz has a T1 connection to Nasdaq head ends and we have a copper x-connect to BT's router and perform BGP. Currently 1408kbps is in use because of the services we consume from Nasdaq. If we add the new multicast services on our line what will happen? Will we start dropping packets because we can't go over the T1 bandwidth?

NASDAQ_MC_TDDS_NYC 256K
NASDAQ_CTCI_CT 512K
NASDAQ_QIX_NY 128K
NASDAQ_MC_BBDS_NYC 512K
pending:
NASDAQ_MC_TDDS_NYC20 768K
** NASDAQ_MC_NTF_ENTIRE_NY B/W??

It sounds like BT is saying this can be done but we would be over subscribing our existing bandwidth. I just want to have an understanding if we would see any issues with the existing services. Thanks for any input.

Jon_Cisco

I don't know anything about these services but I guess this is a question of utilization. Are all of the services always active and consuming a fixed amount of bandwidth or is that just the cap for what they are allowed to use at any given time.

Do you have access to current usage levels?
Is it mostly idle or mostly maxed out already?

Hopefully someone with actual experience has something more specific for you.

ITtech2010

Hi Jon,

Thank you for replying. We checked the current usage levels and we are no where near the full bandwidth allocated for some of the service. We decided to have the extranet throttle the feeds down so we can consume the new production feeds. I have a feeling if we over subscribe we would drop packets. The extranet is in the process of resizing the bandwidth for the services.

santaowns

Depending on your agreement with your provider you and the type of t1. If it's burstable it will allow more than the 1.544mb this should be a temporary solution only as eventually you'll be breaking your agreement. The provider will notice and send you the nasty gram letter buy another t1 and multilink it in a bundle

Rkdrummer20

It will be a good idea to understand about the T1 services under analog and digital services which will help you to talk to your service provider on common ground:

PBX phone systems and other telecommunications equipment often supports both PRI or Primary Rate Interface and T1 lines. What are differences between these dedicated line services and how do you choose the right one for your application?

Dedicated Line Varieties
One hardware interface to supports T1, Channelized T1 and ISDN PRI because they are all variations on the same basic circuit. The differences are in how that circuit is configured for particular applications.

What's Common in These Dedicated Line Services?
The circuit that is provided at the demarcation point is based on the electrical specifications for the T1 trunk line originally developed for the Bell System. It runs at 1.544 Mbps with copper wire for transmit and receive. That's 2 wires total. T1 trunks may be carried on phone wires, coaxial cable, microwave or dropped off by a SONET fiber optic ring.

PRI - Primary Rate Interface
PRI is also known as ISDN PRI or sometime T1 PRI. ISDN stands for Integrated Services Digital Network. There are two speeds of service offered: BRI or Basic Rate Interface and PRI or Primary Rate Interface. BRI is a low capacity service intended for residential and small business applications. PRI is the high capacity service carried on T1 trunk lines between telco central offices and your location.

PRI divides a T1 digital signal into 24 channels of 64 Kbps capacity per channel. 23 of these channels can be assigned as one telephone call each, the equivalent of having 23 separate telephone lines. The 24th channel is used for signaling information and special features such as caller ID and hotel / motel information services. This service provides DID or Direct Inbound Dialing for direct station calling with a 10 digit number. It is a popular service for call centers, nursing homes, multi-point offices which need the ANI automatic number identification or caller ID data.

T1 Services
T1 service can be provided as channelized or unchannelized. In the channelized T1 version, there are 24 channels. Each channel can be a telephone call. T1 gives you 24 phone lines in place of the 23 that can be accommodated with PRI. However, since there is no separate signaling channel, the signaling information that tells when a phone is on hook or off hook is carried within each channel by using or "robbing" the least significant bit. Unfortunately, channelized T1 doesn't provide any capability for ANI or caller ID data. You need PRI service for that.

Unchannelized T1 treats all 24 T1 line channels as one big combined channel for carrying Internet service, point to point data download or VoIP broadband phone. This service is intended to be handled by digital routers, not PBX telephone systems. There are no dedicated phone channels or signaling assigned for switched telephone service.

What Do I Need? What Does It Cost?
We strongly suggest letting a member of our technical team contact you to discuss your particular needs. That way you'll be assured of getting the best service at the lowest cost. There are many flavors of high speed voice and data, including fractional and integrated T1 lines. Our experts can discuss the tradeoffs with you at your convenience.

Please be so kind as to tell us where you want the service located, and provide some basic contact information on the form below. Select the type of service you are most interested in. Most of the time you'll get an instant automated quote that will give you a very good idea of what this type of service costs in your area.

ITtech2010

Thanks for the information guys. I appreciate it.