Customer wants to know if we want to get to Office 365, is this traffic routed directly (from Broadcom) to Office365 or via GCP? (peering)
From a Google to Microsoft peering perspective it's going to be very difficult to do any better than what is currently available (we can't say precisely how many direct peers exist between Microsoft and Google nor at which speed they run, but we can safely indicate that the answer is going to be close to "Many" and "ten's if not hundreds of Gigabit per second").
s an example of this here is the traceroute view from a WSS concentrator in GGBLO1:
[concentrator ~]$ traceroute login.microsoftonline.com
traceroute to login.microsoftonline.com (126.96.36.199), 30 hops max, 60 byte packets
1 google.ier01.lon32.ntwk.msn.net (188.8.131.52) 2.069 ms 2.139 ms ae63-0.lts-96cbe-1a.ntwk.msn.net (184.108.40.206) 2.189 ms
2 ae21-0.icr01.lon24.ntwk.msn.net (220.127.116.11) 2.267 ms ae26-0.icr01.lon24.ntwk.msn.net (18.104.22.168) 2.078 ms ae22-0.icr01.lon22.ntwk.msn.net (22.214.171.124) 2.368 ms
As you can see from our side the latency from Google to Microsoft is minimal albeit this is just the network ingress, path. There will be more latency from Microsoft internal routing and servers responding.
GCP peering with Microsoft is available for all GCP regions except the mainland China currently, albeit Broadcom is moving their China datacenters onto Azure which should reduce latency for Office 365 access from China.