Re: Metro Node - possibly a part of the issue
Certainly there should be a failover device, however for maintenance the routers I use have two routing engines, one is active the other is standby. To do maintenance/upgrades on them you simply failover to the other. I guess I haven't worked with enough different types of equipment to know if this is common; however, maintenance and upgrades should take place during the slowest periods and customers should be made aware long enough before the maintenance that they can plan for potential issues. Like not exchanging database info with head office and such.