How Many Hops is Too Many Hops? Is Latency Hurting Your Business?

Let’s face it, we’re in the age of now.  Who doesn’t find it annoying when network latency forces you to wait while streaming video is buffering, degrades important VOIP calls or slows load time for critical applications?

As businesses are only as agile as the applications that support them, it’s critical to address the underlying causes for any latency issues you might be experiencing.Network Latency Is Less Ideal

The principal cause of latency lies in the route used to forward data from point to point. Routers are the devices that manage the path between any source-destination pair of addresses. They determine, usually, the shortest path between two points.

I’d like to share a few thoughts on how data moves across the internet to get from point A to B. Then we can talk about what is meant by “too many hops.”

Routers used by large enterprises, VoIP providers, most ISPs and other organizations that connect to two or more ISPs use Border Gateway Protocol (BGP) to route traffic through the Internet. = Whereas Interior Gateway Protocol (IGP) manages the low level details of Internet routing with methods like Open Shortest Path First (OSPF), the Border Gateway Protocol attempts to find the shortest path between two points using Autonomous System Numbers (ASNs).

ASNs are issued through the American Registry for Internet Numbers, commonly known as ARIN. (In Europe, Central Asia and the Middle East, an organization in Amsterdam known as RIPE handles Internet number assignment).

ARIN explains ASNs as follows: “An Autonomous System is a connected group of IP networks that adhere to a single unique routing policy that differs from the routing policies of your network’s border peers. An ASN is a globally unique number used to identify an Autonomous System. An ASN enables an autonomous system to exchange exterior routing information with neighboring autonomous systems.”

Once an organization is given an ASN, the BGP router accesses a list of Internet routes from its BGP router neighbors to find a path that minimizes the number of autonomous systems involved in forwarding data. That is, the router consults “nearby” routers to choose the shortest path.

Now that we’ve delved into those details, let’s take a look at a simple way to determine if your data is taking “too many hops.” The simplest test is the Windows program TRACERT, which you can launch using the CMD.exe command prompt. (Use TRACEROUTE for Linux or Apple computers). The program will show you the name or IP address of every router along the path that forwards your data toward its final destination, along with the time taken for each hop.

 

Depending on the ISP you use, data moving from you to its destination may have to make 10, 15, 20 or more hops across multiple ASNs. (There are about 20,000 ASNs in use worldwide today). To avoid the latency that’s bound to develop, it’s desirable to minimize the number of ASN’s on the route. One company, NTT Communications, solves the latency problem by using only one ASN (#2914) to span the entire globe.

With exchange points around the world, your data gets to any access point on NTT’s Tier 1 network in fewer than five hops. That means your data travels smoothly around the world and back with fewer delays. For VoIP service where latency can’t be tolerated, NTT Communications is our choice of ISP partners.

Additional Resources:

Networking 101: Understanding BGP Routing

Overview of Autonomous System (AS) Numbers