We are having a leased line installed by British Telecom, they have routed the fibre via our telecoms 'cupboard' (enclosed glorified cupboard in our reception area) which has no airflow and only 2 medium sized plastic vents (top & bottom).
The existing Samsung digital telephone system is in this cupboard in a 12U rack cabinet (with no space). It generates some heat but nothing substantial - we've had no problems with it getting too hot/overheating even with the recent heatwave our area of the UK has experienced.
My question is, BT are supplying (leasing?) a Cisco 2921 ISR as part of the install. We were not expecting anything quite this big (our existing lines are 2 standard DSL lines coming via this cabinet and then routed using copper to our routers in our server room). BT have said they cannot site the 2921 anywhere else than this telecoms cupboard. The 2921 is not wall mountable and we have no additional room for another rack cabinet in the cupboard.
Our current running solution is some kind of small table to support the 2921 so we can place it in the bottom of the cupboard. But I have concerns over the airflow (there is very little) and the possible heat generated by the 2921 in this enclosed (3.5m X 4m X 2m) space. Are we going to be ok without any additional cooling/fans?