Lexmark IBM 9077 - Manual (Page 31)

Router Node 13
The GRF uses a crosspoint switch (see Figure 7) instead of an I/O bus to
interconnect its adapters. This switch is capable of 4 or 16 Gbit/s (model
dependent) and gives better performance than the MCA bus.
Figure 7. GRF 400
In conventional routers, each packet is processed at each gateway (also
called
hop) along a path. The processing is done at the Layer 3 level (see
Figure 8 on page 14) and requires a router’s CPU to process both the packet
and the route information. Conventional routers use shared resources, which
leads to congestion and poor scalability and performance. Software-based
route-table lookups can be very slow, if the route-table is not in cache.
Media Cards
LAN/WAN Route
Table and
Lookup
I/O
Buffering
IP
Packet
Forwarding
Switch Engine Interface
LAN/WAN Interfaces
IP Switch Control Board
Route
Manager 4Gb/s
Crosspoint
Switch
1 Gb/s to each Media Card
T3-OC12