Zayo vs Coent


We are in a facility where my only options are Cogent or Zayo. We plan on getting a 10G connection for a web crawler using v4 only. Looking for feedback on either or (keeping the politics out of it).



Zayo is the former Worked well for me at previous $job.
Cogent is Cogent. Refer to the list archives for experiences with

Bill Herrin

Comparing networks and performance I believe zayo will outperform Cogent in most places but I’ve heard nightmares about dealing with Zayo’s account managers and billing reps.

Cogent is great at their price point and you will get a very sweet deal for a 10G circuit and their account managers and NOC both have been great for us.

I have both Zayo and Cogent at my location in West Chicago, IL and have found that most of my traffic transits Cogent. I haven’t had much in the way of issues with the Internet service of either but Zayo does seem to have gone down hill in terms of support quality since they bought Abovenet.

I’m aware of the Cogent peering issues but haven’t investigated them fully. Recently, there was an extended service outage on my Zayo 1G link due to dark fiber issues on a private network which left me with Cogent only for about a week and had no support calls because of it. YMMV.

Ryan Wilkins

Zayo is probably a tad better in the network quality, but… Zayo’s NCC is awful when it comes to fixing or resolving anything, even something as simply as add a default route to my BGP session. And its takes forever, like a whole day waiting in queue. Cogent, you can call, and 15 minutes your done.


$dayjob hat off: I’ll add that they often times use the same fiber for the last mile (hence why they’re both on-net at that building), so if you get both with the intention of redundancy, you could potentially be taken out by a single cut unless you harp on the point that they need to be fiber diverse and asking for proof (drawings, etc.) never hurts.

Using and Zayo KMZs loaded, i can’t see neither on this location (maybe they forgot to update the kmzs)

Screen Shot 2018-11-09 at 11.38.08 AM.png

You can join our Slack Channel , there are many people who has regional dark fibre knowledge (100+ people) across the world. To discuss further,

Zayo will provide you all of the internet

Cogent will provide you with something that is not all internet, it is missing HE and Google on ipv6.

If you love yourself and your organization just peer with Zayo and not look back.

We have 10G IPv4 circuits with both Zayo and Cogent getting full routes. One major difference is the maintenance windows - when Cogent has maintenance, things get weird for hours at a time.

My cogent is pretty good… I had 10 gig for a few years, then dual 10’s Lag’d together for about year or so, and now 100 gig for about 2 months. So it’s been about five or six years that I’ve been with cogent

They usually are knowledgeable when I talk to them and they are able to do what I ask of them. They usually don’t have to hand me off to somebody else.

Cogent has good DDOS RTBH also. I trigger a /32 and it’s immediately black holed in the cloud.

Cogent does however have an issue with ipv6 peering with google. I currently have my v6 ebgp session shut down with them because of this. Moving forward and doing more V6 in the future, I will have to figure out how to deal with us.

I’ve also had Spectrum, ATT, Telia, all good as well. I’ve have no experience with Zayo, so I can’t speak to that


Only the parts for which someone has remembered to call in updates and/or which Zayo has remembered to apply to every manually maintained per-session prefix list, or for which someone has badgered them enough to switch to max prefixes only. They have an incurable allergy to IRR, and it's a bundle of fun to sort out when something gets missed.


I actually went through this exercise recently with Cogent, Zayo, and two other providers. The requests were all made via email at roughly the same time. HE was by far the quickest (I think under an hour), with Cogent being about half a day initially (but they did miss a BGP session, which was fixed within a few hours of notifying them), and Zayo taking about 3 days, with a follow up call around the 2 day mark.

From an outage standpoint: I’ve had three outages with Zayo, the first being the most painful (left hand doesn’t talk to right hand), the second was brief and they provided an RFO same-day, and the third being similar to the first, but resolved quicker because I was able to reference details from the first. I’ve never had total outages with Cogent on my transit, but I have on transport, and they were relatively quick to respond, resolve, or provide details from third-party providers each time. From a quality standpoint, I “feel” like the Zayo transit is better, but maybe that’s because I pay more for it. I think from a peering standpoint, I tend to see better paths through Zayo. I’ve seen Cogent send traffic way out of region for several content providers - causing customers to complain about high latency to Google.