Media Links MD8000 Series, Руководство по эксплуатации

Страница: 45 / 98

MD8000 Rev. H MD8000 Series Transport System Summary 2.25
Hitless Switching with a Single SWCNT Board
Figure 2-23 illustrates single SWCNT board operation. The originating Channel Service board
(VTX) transfers identical IP packets with different destination addresses to the SWCNT
boards through the same route. The L2SW in the SWCNT board transfers the IP packets to a
separate Trunk board to enable the use of physically separate network circuits.
Figure 2-23: Hitless Switching - Single SWCNT Board Operation
Figure 2-24 illustrates a little further in detail the behavior of the Channel Service board and
the SWCNT board. Under the single SWCNT board configuration, as shown in Figure 2-24,
two identical Stream-packet streams (except their destination address) can be routed through
the completely independent circuits between peer SWCNT boards.
In this mode of operation, two identical Stream-packet streams (except their destination
address) are transferred in one physical circuit between the Channel Service board and the
adjacent SWCNT board in a TDM method.
Figure 2-24: Operation of SWCNT and Channel Service Boards
Network
VTX
Encoder
LINE1 TX
LINE2 TX
Trunk
Board
MD8000
L1 P#6
MD8000
L1 P#1 L1 P#2 L1 P#3
L2 P#1 L2 P#2
VRX
FIFO #1
FIFO #2
Decoder
SWCNT
Trunk
Board
L1 P#7 L2 P#7
L2 P#6
LINE1 TX
LINE2 TX
L1 P#5 L1 P#4
L2 P#5 L2 P#3 L2 P#4
Trunk
Board
SWCNT
Trunk
Board