Chapter 3. Configuration61200659L1-1 MX2800 STS-1 User Manual 3-5VT ModeThe STS-1 can frame the 7 VT groups as either VT1.5 or VT2.When set for VT1.5 (T1), all VT groups are set for VT1.5[TU=11]at 1.728 Mbps and the ports are set for T1 at 1.544 Mbps. When setfor VT2 (E1), all the VT groups are set for VT2[TU-12] at2.304 Mbps and the ports are set for E1 at 2.048 Mbps. When setfor VT2, the last 7 VTs, VT 22-28, become unavailable. All E1ports are available for mapping.Protection ConfigurationThe MX2800 STS-1 houses two controller cards for 1:1 protectionagainst hardware failure. The two cards can also provide networkprotection, supporting two STS-1 circuits simultaneously. Theselections in this menu allow you to customize the unit’s protectionsetup.Active ControllerThis field displays A or B, indicating the active controller card. Thissetting can be used to force the controller cards to switch. Forexample, if controller card A is active and you select B, a switch-over occurs immediately.Setting The unit switches controller cards if...1E-3 more than one out of every 1,000 bits received on theSTS-1 contains a code violation.1E-4 more than one out of every 10,000 bits received onthe STS-1 contains a code violation.1E-5 more than one out of every 100,000 bits received onthe STS-1 contains a code violation.1E-6 more than one out of every 1,000,000 bits received onthe STS-1 contains a code violation.
