I run DSLstats (from a linux host inside my network) to monitor some stats from my zyxel vmg1312-b30a modem in bridge mode (also a broadcom modem suited for up to 100/40 profile 17a VDSL2 links), but that is considerably less restricted and hence DSLstats can get the required telnet login into the modem and then can run/collect/parse the output of broadcom's xdsl utility. I am pretty sure Deutsche Telekom had the manufacturer of the Entry 2 (Sercomm IIRC) nail down all hatches, so neither telnet not ssh login are likely to be available in modem mode, sorry.
(I also use @takimata's nice collectd script to get data from the modem into the openwrt GUI (which also requires telnet access), as well as his method to keep the RRDtool database persistent so I can look at aggregates over more than the current uptime of the router...)