I recently upgraded my service and received an XB7 modem (CGM4331SHW) to upgrade from a hitron modem.
After installing and activating the new modem in bridged mode I discovered a couple of networking related issues:
1) 6in4 tunnels via IPv6 tunnel broker no longer work.
Issue has been acknowledged per this post https://support.shaw.ca/t5/internet-discussions/xb6-blocking-6in4-ipv6-tunnel/m-p/32143#M11333
2) network communication/throughput between two Internet nodes connected to the modem's LAN ports is choked almost completely.
My setup
Ethernet connection from the modem is to my router which serves my LAN.
A second connection is to a standalone web server.
Each connection receives an Internet IPv4 address assigned by Shaw's DHCP.
Connections to the web server's external FQDN or IP address do succeed, but the resulting communication between the 2 nodes averages around 14KB/sec and only in 2 second bursts every 10 seconds. I am unable to successfully establish any type of encrypted connection between the two nodes such as SSH or https: as it appears TLS encrypted sessions time out during the handshake process.
Connecting to web site unencrypted via port 80 does work but very slowly. The web site which normally loads in a couple of seconds with encryption, took almost exactly 10 minutes to load without encryption. Running an indefinite ping between the nodes shows a clean consistent 14ms average response time with zero dropped packets. Everything connects and communicates fast and normal from any other external Internet connected node such as when browsing to the web site on my cell phone or from work.
The problem is only the communication directly between the Ethernet nodes connected to the modem's LAN ports.
My hope is that I can get confirmation that another Shaw customer this issue or perhaps someone could test this internally and submit another escalation to the vendor if confirmed. I too would be happy to test any firmware fixes/updates.
Update: Reverting back to my previous hitron modem immediately resolved both issues without any configuration changes. I'll revisit Fibre+ and the XB7 modem later on when presumably the firmware bugs are eventually ironed out.
