Fastly Debug App - Server Location?

General
1

Hi folks,

Excuse me if this is a dumb question - I’m a bit of a noob here.

I am located in Toronto. But when I load the Fastly Debug App, it says it is connecting to the Montreal datacenter, even though the latency to the Toronto datacenter is lower. Why is this?

Besides general curiosity, I’m also asking because I’m worried that content on the Fastly network is being sent to me from Montreal rather than Toronto.

2

Hey @Senner87, can you send over the results for us to review? The short answer is that many factors may influence a specific client’s connection experience, so it’s not easy to point to a single definitive answer.

1 Like
3

Hi @aspires. I assume you want the text block? Here it is:

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

Here’s a screenshot of the page. Another one in the following post, since I’m being limited to one per post.

Fastly Debug App Screenshot 1
Fastly Debug App Screenshot 1704×794 18.2 KB

1 Like
4

Second screenshot:

Fastly Debug App Screenshot 2
Fastly Debug App Screenshot 2692×551 17.5 KB

5

Hey @Senner87 thanks for sending that over. These are some data points I pulled from the block:

"popLatency": {
...
    "yul": 9,
...
    "yyz": 2,
...
}
...
  "popAssignments": {
    "ac": "yyz",
    "as": "yul"
  },

YYZ and YUL are the lowest latency options available, and the functional difference between 2 and 9ms is insignificant.

What the second block means is:
ac – our anycast routing system preferred Toronto at the moment of measure.
as – our DNS routing system preferred Montreal at the time of measure.

I say “time of measure” intentionally, as our routing systems constantly measure and make real-time chances based on latency, loss, and other factors on a near minutely basis. That weighting is also different for the Anycast vs. DNS network. Latency is a huge factor in the reliability measure, but it’s not the only factor in the decision system.

TL;DR – we route based on a picture of reliability, which includes latency, but is not exclusively bound to latency

If you’re extra curious, we have some blog posts on the tooling if → Turning a Fast Network into a Smart Network with Autopilot

6

Hi @aspires,

Thanks for the info. I didn’t think a difference of 7ms would be insignificant.