Bandwidth vs Latency are the two biggest factors in determining the true Internet speed of a connection.  It is also probably the most misunderstood aspect of data networks when deciding to optimize or upgrade bandwidth speeds.   When looking at Latency vs Bandwidth, you have to take into account both metrics together when comparing different types of data network connections and speeds.  

Bandwidth is a measurement of the size of a data connection (measured in Kbps, Mbps, or Gbps), this is the physical capacity, similar to a road (one lane, two lane, four lane, etc).   Latency is the measurement of speed that data travels across a network (measured in milliseconds - ms), similar to how fast a car travels on the road.  Lower latency equals a faster speed,  so a large bandwidth connection along with a low latency network is ideal when looking at Bandwidth vs Latency.

Internet latency varies based on the type of network connection you have.   T1 latency is the lowest, DSL latency falls in the middle, and Cable Internet has the highest bandwidth latency.   The reason why one type of connection has higher Internet latency vs another comes down to two main factors.   One is how the network is designed, is it a shared network or a dedicated network connection?    The second is how many hops or legs does that network have, for data to travel from your location to the destination (and back)? 

Both Cable and DSL Internet are shared network connections, meaning you are sharing network capacity in your area with numerous subscribers.  This is the reason why there are fluctuations in the bandwith speeds and Internet latency depending on the time of day, even though you bought a service that was supposed to have higher Internet speeds.   With DSL and Cable connections, there are no guarantees on your service for up-time, latency, packet loss, or repair (aka Service Level Agreement – SLA), it is called a “best effort” guarantee.    With a T1 line (or Ethernet, DS3, Fiber Internet), the connection is dedicated and the bandwidth is not shared, you are the only one using that bandwidth.   Internet speeds are always the same not matter the time of day, and service comes with a Service Level Agreement for guaranteed network performance.  This is the first factor in Bandwidth vs Latency issue.

Hops are basically stop lights on the information superhighway which allow traffic management (done by routers and switches).  DSL and Cable networks, because they are shared and typically congested, have many hops before they even get to the Internet.  Each of these hops creates milliseconds in delay which add up to slower data speeds (higher latency) and reductions in bandwidth based on network congestion.  A T1 network is a dedicated point to point circuit between your location and the Internet, with a minimal amount of hops or delays (lower latency), a dedicated Internet connection will always be faster than a shared data connection.   This is why dedicated Internet (Ethernet Internet, Fiber, DS3, T1) is used by businesses and shared Internet (DSL, Cable) is mostly used by residential and small offices.  This is the second issue in Bandwidth vs Latency. 

So when looking at both metrics, you need to take into account the issues described herein.  If you only look at part of the Latency vs Bandwidth equation you will not be effectively evaluating the reasons why your Internet connection is slow.   Here are some useful Network Tools to help evaulate Bandwidth vs Latency issue. 

Ethernet Broadband Internet is an emerging technology which offers high speed Internet access at a fraction of the cost of T1, DS3, or OC3 lines.  Broadband Ethernet service is delivered to a location in a number of ways, depending on the available telecom facilities and speeds in the area.    The most widely available service is Ethernet over Copper (aka EoC), which is basically Ethernet over phone lines.   The benefit of this Ethernet Broadband service is that almost every building has copper phone lines.   The cost for those lines are minimal, which means lower Ethernet over Copper Pricing.   Broadband Ethernet over Copper speeds depend on distance from a phone company central office (CO).  Internet speeds available are 2Mbps to 20Mbps, with  some providers now offering up to 100Mbps and 200Mbps Ethernet over Copper.  Installation time frames for Ethernet over Copper are usually 15-45 days. 

Another Ethernet Broadband service is Ethernet over T1 (aka EoT1 or EoDS1), which is similar to Ethernet over Copper Internet access.   Like Ethernet over Copper, it uses the existing copper facilities in a location to build T1 circuits.  These lines are then used to deliver the Ethernet over T1 service.   Unlike Ethernet over Copper, there are no distance limitations, other than having the right Ethernet Broadband equipment in the local phone company central office that services your area.   Some Broadband Ethernet providers even offer Ethernet over DS3 Internet to provide higher bandwidth speeds (over 10Mbps).  Generally service is available for speeds of 10Mbps to 100Mbps Internet, with Ethernet over T1 Pricing a little higher than EoC.   Installation timeframes are typically 30-45 days.

The last Broadband Ethernet access is Ethernet over Fiber (aka Metro Ethernet Service).   This type of Ethernet connection uses fiber optic lines to deliver Ethernet Broadband speeds from 10Mbps to 1Gbps+.   This Ethernet Broadband service is typically available only in metro areas.  Ethernet over Fiber connections are delivered to buildings that are already fiber lit, either by the local phone company or competitive telecom providers.   If the location is not fiber lit, but there are fiber networks in the area, they will usually build a fiber connection to the building.   The construction costs to build an Ethernet over Fiber line can be substantial, but in most cases the provider will absorb those costs with a longer contract term.    The benefit of Ethernet over Fiber is that the speeds are the highest currently available, with the ability to upgrade and change bandwidth without much effort.  Installation time frames can be long, with average installs running 30-120 days, depending on the amount of contruction involved to deliver service.   On the bright side, fiber optic Ethernet technology is future proof, and will be the cutting edge service delivery method for many years to come.  Ethernet over Fiber Pricing is also very competitive for higher bandwidth speeds.