AS 41095Looking Glass

What is Looking Glass? and why ISPs need this tool so much? Every newbie in the Telco world must have asked this question at least once but had some difficulties in finding a useful answer, therefore, with this article, IPTP Networks will help you go through the definition and how to use this Looking Glass tool, as well as how to understand its results.

Looking Glass is the tool that provides users with information related to an ISP’s backbone routing and the efficiency of their network. It allows you to search up our routing information via IP address (or prefix) and router with only a few simple steps. This tool lets you search for the information in 3 types of queries: BGP, ping, and traceroute.

Benefits of the Looking Glass tool

The Internet is made up of many separate connections, and these connections can occasionally fail. The Internet is also made up of a number of other networks, some of which have trouble communicating with one another. This could be a BGP peering issue or another type of connectivity issue.

In these cases, Looking Glass is an essential tool for troubleshooting Internet-related networking problems from the servers to the end user’s devices. It is also a reliable friend for you in determining who can offer the best IP transit service.

How to use the Looking Glass tool

To start the search:

• Select the query you want (BGP, ping, trace)
• Type in the IP address or prefix
• Choose the desired Router from the dropdown list
• After every field is ready, press “Run”

The meanings of each query:

• BGP (Border Gateway Protocol) routing: shows the routes available from the source IP address to the selected routers.
• Ping: allows you to view round trip time between a selected router and a specified IP address.
• and Traceroute: helps you see how packets travel, including seeing hops encountered in the path, across an IP network and the router.

Understand the results

By using a practical study case:

With the BGP query

The above picture is basically what we get when we run the Looking Glass network tool using the BGP query. Based on the results of Looking Glass, in NIKHEF, we can see there are 2 routes from IPTP to the IP range “5.44.136.0/21”, in which, the route through Lumen with IP peer of “212.72.47.241” has the best quality.

Specifically, we can see the number “3356” is Lumen’s AS number and 3292 is Tele Denmark’s ASN. And 212.72.47.241 is the IP that Lumen uses to establish a BGP session with IPTP.

With the Ping query

The results that appear will show you how many data packets the system has sent to the destination and returned to the source. Based on this knowledge, you can find out how much possibility (in percentage) is that the router can “ping” to the IP address successfully (In this example, it is 100% with 5/5 packets successfully sent and returned). Moreover, in the below lines, you can also see the minimum/average/maximum round-trip time for those packets to travel from the source location to the end user’s devices or servers (in this case, 95/95/95 ms).

With the Traceroute query

Talking about the same “trip”, but instead of showing the total round trip time, the Traceroute query illustrates all the hops that occurred on the path and the time those data packets took to go through those hops.

In wired computer networking, including the Internet, a hop occurs when a packet is passed from one network segment to the next. The hop count refers to the number of network devices through which data passes from source to destination. Since data storage-forwarding, as well as additional latency, is often incurred per hop, the larger the number of hops between source and destination, the lower the real-time performance will be.

(Disclaimer: The information and pictures above are only used for demonstration purposes and not for research or any other purposes)

To read more about our global Internet connectivities, please take a look at our IP Transit service.
To do further investigation of transcontinental latency, kindly visit our Best Path tool.

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