User guide

Appendix C - Redundancy C-13

N:M Hub Modem Redundancy

Description

The N:M Hub Modem Redundancy service provides for the protection of criti-

cal VMS network modems operating in Hub mode and enhances overall

network reliability.

The N:M redundancy in VMS version 3.x has the following characteristics:

• Protects Vipersat Hub modems from equipment failure

• Is a VMS controlled feature

• Does not require any external switching hardware

• Preserves the satellite network configuration and state information during

hardware failure

• Is scalable and flexible to satisfy the unique requirements of each network

N:M redundancy increases reliability by backing up critical primary central hub

components with standby backup units. In a traditional 1:1 or 1:N redundancy,

switching is handled by combining transmission equipment into logical

mechanical switching units. These software/hardware units then interconnect

the primary transmission units I/O through a physical mechanical maze of

relays and cable jungles. They also become the next point of failure in the reli-

ability hierarchy.

The Vipersat solution relies less on a mechanical backup system architecture,

decreasing the single point of failure. The Vipersat software-driven N:M redun-

dant architecture is completely IP packet controlled with the only hardware item

being an IP controlled electrical power switch.