In reply to a post by RobertoS:

For instance, I started from the assumption that the timeout at 4 20 ms * 20 ms 195.66.225.91 << LINX LON1 / Juniper LAN was due to something prior to that, specifically to do with zen. I wouldn't expect that LINX routers are going to timeout on a ping. It's far more likely it was dropped in one direction or the other in the "zen network".

The IP you see isn't a Linx router. It is an IP of a Linx member and will be the Linx member's device. In this case, Fastly, who provide a CDN to BBC.

The Linx member can apply whatever policy they want to their interface, some place very restrictive limits on diagnostic protocols like ICMP so that it can concentrate on the more important job of routing as Ignitionnet as mentioned in a more technical way. Some Linx members don't respond to ICMP at all.

The reverse route may not even be the same from Fastly to the end end user, so the "loss" seen may actually have been caused by a completely different path having an issue outside of the Linx, Zen or Fastly network.

Matt

Heh! Hehe! Matt . Thanks. The plot thickens.

That'll teach me not to take labels inserted in capitalised bold by someone I realise knows more technically than I do too literally . Next time we have anything similar I will check for this sort of thing .

As for the concentrating on doing the real job rather than bother with "user" diagnostics, that I fully understand. As I explained to Ignitionnet. It's a basic feature of tracert that we all learn very quickly.

I still believe that zen does have some bottleneck problems, as evidenced by more and more postings by their users over the last year or so. The fact my interpretation of hop 4 is probably wrong does not rule that out.

In particular the single 85ms of three in hop 2 and the single timeout surrounded by the 20ms ones for hop 4, the router in question, I suggest do point the finger at either the zen hop 2 router or something earlier in the zen network. As Ignitionnet himself propounds.

Edited by RobertoS (Wed 15-May-19 00:28:32)