Different T1s and Services
All T1s Are Not the Same
This blog is a very important one. Today, I am going to go over the different types of T1s and the four reasons why they each may be optimized or slowed down.
First off T1 Internet consists of two parts: The local loop and the port.
Pricing for the local loop is covered under a tariff filed with your state Commerce commission. The T1 circuit is provided by the ILEC (Incumbent Local Exchange Carrier) such as SBC, Qwest, Ameritech, Verizon and the rest of the Baby Bells and includes the local loop, the copper, and the initial configuration. A clear channel full T1 loop is made to provide 1.544 Mbps full-duplex (1.5 Mbps upload/download at the same time.)
The second component is called the “port.” The port is the pipe to the Internet at your Internet Service Provider. All ports are not the same and may be sold as fractional, burstable, shared, full, protected, tiered, or bonded. The reliability and performance of your Internet connection highly depends on the quality, capability, connectivity, and engineering of your ISP. In other words, if your ISP has a shoddy or oversubscribed port to distribute your Internet, you’ll get a shoddy connection. It’s sort of like getting clean drinking water pumped into a dirty system. Clogs in a bad water distributing system can back water pressure and that clean water can become dirty and undesirable. This is why T1s will show a huge discrepancy amongst different vendors. So remember, your T1 and local loop (the actual physical circuit from you to the ISP provided by the ILEC phone company) may be able to carry 1.5Mbps of data, but your ISP may not have the bandwidth to deliver that much data. This is why you some T1 lines sold as full 1.5Mpbs will only perform at 768kbps. The line is 1.5Mbps but the port or service isn’t.
Let’s look at a breakdown for some of the different lines.
- Frame Relay T1 is pretty self-explanatory. They are T1s with bandwidth that runs over a frame relay network
- Bonded T1 is more than one regular T1 line “bonded” or joined together to increase bandwidth speeds. You would estimate an additional 1.5Mbps for each bonded T1, so 2 lines equate to 3MB, 3 lines equals 4.5, and so on.
- Hybrid T1 is a T1 plugged into a DSLAM and runs over a DSL ATM/Frame Relay network. DSL quality bandwidth, poor “DSL” network quality, lacks a T1 backbone connection, and no prioritizing of your packets or service. It is also known as FRoDSL (Frame Relay over DSL), TeleXtend, or Frame Relay T1.
- Shared T1 is usually run to an MTU (multi-tenant unit) and split up into separate data networks for customers that choose to use the Internet service. This is generally an excellent and cost effective solution if the T1, routing, and firewalls, are properly designed and managed by a competent ISP.
- Fractional T1 means you would be sharing a T1 line with one or more subscribers. The fractional T1 still maintain their speeds, so for the average user, it’s still more than enough. Just like cable and DSL, there are different plans you can choose from, such as speeds of 386kbps, 512kbps or 768kbps.
- Burstable T1 is a T1 that won’t guarantee full speed at any time.
- Protected T1 is a T1 that’s wired with a redundant dedicated wireless T1 connection, on diverse paths, with intelligent routing for increased reliability. If the wired T1 local loop fails for any reason, the routing will automatically switch to the wireless loop. Internal and external IPs, VPNs, and service is all maintained without interruption.
- Clear Channel Full T1 is a real full T1 to the backbone or to the reseller that takes you to the backbone.
The above types of T1s make your decision pretty difficult when shopping for T1s, especially when you don’t know about all the different types of services available. Advertising is broad with the way they word things; like “cheap T1 service.” I can tell you that I’m selling cheap cell phone service, but you would immediately be leery of what you’re offered, the phone you get, the network, etc. Treat buying a T1 line the same way you would buy anything else.
Now the above mentioned T1 lines all have their benefits, which affect pricing, so make sure you know what you’re willing to spend and what do you expect for your price. Once you’ve read this blog or researched the different T1 lines available, look into the way the ISPs you’re interested in administers their service.
Let’s say you decided on the Clear Channel T1 because it’s a full T1 line. Done deal right? Wrong. Different service providers may skimp you while you’re unaware. I’ve covered most of these things in this blog, but let’s review and make an overview look at things you should pay attention to.
- Committed Information Rates (CIR): This is the guaranteed bandwidth you are guaranteed, usually spelled out in the
SLA. A 90% CIR means that you will have at least 90% of your bandwidth available to you at all times. How an ISP can screw you is they may be a frame relay provider and offer you DSL-like prices speeds for full T1 prices. As I said in my CIR article: “if you are paying for a 1544K frame relay T1 and your provider offers a 384K CIR, this means your ISP will guarantee only 384K Speed for your 1544K T1. YES this means you will be paying FULL PRICE for essentially what is a 384K T1 Line, that may or may never reach the full 1544K speeds you think you are paying for. Worse, most frame relay providers such as the local phone company will only guarantee 128K, or 64K, or even 0% CIR. You could wind up being stuck in a contract for 2 or 3 years paying close to $400 a month for a 64K dial-up speed T1 line.”
- Tier or Upstream Provider (affects quality): The unwritten “tier hierarchy” are they are: Tier 1 (A network that peers with every other network to reach the Internet), Tier 2 (A network that peers with some networks, but still purchases IP transit to reach at least some portion of the Internet), and Tier 3 (A network that solely purchases transit from other networks to reach the Internet.) A Tier 1 does not have any alternate transit paths so Internet traffic between any two Tier 1 networks is critically dependent on the peering relationship. If two Tier 1 networks arrive at a deadlock and discontinue peering with each other (usually a decision by one side), single-homed customers of each network will not be able to reach the customers of the other network. This effectively "partitions" the Internet, so that one portion cannot talk to another portion, which has happened several times during the history of the Internet. Those portions of the Internet typically remain partitioned until one side purchases transit (thus losing its "Tier 1" status), or until the collective pain of the outage and/or threat of litigation motivates the two networks to resume voluntary peering. It is important to remark here that Tier-2 (and lower) ISP and their customers are normally unaffected by these partitions because they can have traffic with more than one tier-1 provider. Because the "tier" ranking system is used in marketing and sales, a long-held though generally misguided view among customers is that they should "only purchase from a Tier 1". Because of this, many networks claim to be Tier 1 even though they are not, while honest networks may lose business to those who only wish to purchase from a Tier 1. The frequent misuse of the term has led to a corruption of the meaning, whereby almost every network claims to be a Tier 1 even though it is not. The issue is further complicated by the almost universal use of non-disclosure agreements among Tier 1 networks, which prevent the disclosure of details regarding their settlement-free interconnections.
- Service Level Agreement (
SLA): Every company will have one of these, and most of them have it posted on their websites. An SLAis part of a service contract where the level of service is formally defined. The main purpose of an SLAis to specify the levels of availability, serviceability, performance, operation or other attributes of the services like billing, or even penalties in the case of violation of the SLA. SLAs protect businesses by making access providers pay penalties to the customer for downtime that exceeds a specified total in availability. When agreeing upon the Service Level Agreement, you may want to include additional provisions, such as negotiating a more reliable connection that includes alternate routes for your data, create on-call backup circuits, and attempt to specify more severe penalties for service provider failures.
- Oversubscription Ratio: Oversubscription is a practice used by ISPs to optimize their resources and maximize profits. Full Clear Channel T1 lines are exclusive to one customer at 1:1, but it’s common to find 4:1 to 20:1 user to line ratios. In my blog on oversubscription, I stressed not to mistake a T1 line with T1 service. You may have a T1 line running into your building, but it may be connected to a DSL network or something. With oversubscription, an ISP can be deceptive and claim you are getting a full T1 at 1.5Mbps which is true because the T1 line circuit capacity itself is 1.5Mbps, but that doesn’t mean the bandwidth or throughput speed coming through it will be. On top of this, even if it’s not frame relay, the T1 could be oversubscribed and you would not get your speed throughput all the time. So if that happens, you are averaging 384k all day because the line is oversubscribed to lots of people. You are essentially paying somewhere around $399 for a “discount T1” at 384K when you could have bought a clear channel T1 for $499. You would be guaranteed no oversubscription and get 4x the speed for $100 more. It's basically paying $399 for a cable modem since there is no consistent speed which amounts to one big rip-off.
If these problems exist to degrade performance of a clear channel T1, can you imagine how much worse it would make your Hybrid T1 or Burstable T1 connection?
All these above can affect your T1 quality and performance and determine whether you are getting a good value for what you are paying or getting ripped off. A reoccurring theme in this blog is to do your research and to read your contracts before making any decisions. I keep stressing that the contract you sign maybe the service you stay with for the next 2-3 years, so why not make it a good 2-3 years for your company.
One last special thing worth mentioning: VPN (Virtual Private Networks): if you plan on setting up a VPN network then making sure you can get the fastest most reliable bandwidth possible with your T1 service. This is because when your VPN can slow your traffic considerably on a network that is already considerably slow at times. Your speeds can take up to a 50% performance hit when using a VPN connection. This can cause a major disruption in your business and severely hurt your productivity and you will need to add bandwidth. But if your provider is already giving you 1.5Mbps, you can’t, and so you’d be stuck.
I hope I’ve helped you guys so far in your search for an Internet service that will benefit your company. For years, T1 retailers have been selling subpar service to unsuspecting customers. Hopefully you found this blog very informative. Please read my next article: price shopping for a T1 line, to supplement the information I gave today.