VIP Port Adapter Functions
Token Ring Overview
The following sections describe Token Ring specifications, physical connections, connection equipment, and cables and connectors. Figure 14 shows the 4R port adapter installed on the
Figure 14 VIP with One 4R and One 4T Port Adapter Installed (Horizontal Orientation Shown)
Bus connector
Microcode | Port adapter | |
ROM U1 7 | ||
handles not shown | ||
| ||
DRAM |
| |
SIMMs |
| |
4R in port | 4T in port | |
adapter | ||
adapter | ||
slot 1 | ||
slot 0 | ||
|
EN |
|
| RC |
| CD |
|
|
|
|
| CD |
|
|
|
|
| CD |
| FAST SERIAL | CD | |||
TD | TC | RD | LB | TD | TC | RD | RC | LB | TD | TC | RD | RC | LB | TD | TC | RD | RC | LB | |||||
H5985
EN |
| RD | RC |
| CD |
TD | TC | LB |
Note Current VIP configurations support only one 4R port adapter and one 4T port adapter. Single and dual 4R configurations are not available. Port adapters have a handle attached, but this handle is not shown to allow a full view of detail on each port adapter’s faceplate.
Token Ring Specifications and Physical Connections
The term Token Ring refers to both IBM’s Token Ring Network, which IBM developed in the 1970s, and to IEEE 802.5 networks. The IEEE 802.5 specification was modeled after, and still closely shadows, IBM’s network. The two types are compatible, although the specifications differ slightly.
Token Ring and IEEE 802.5 are token passing networks, which move a small frame, called a token, around the network. Possession of the token grants the right to transmit; a station with information to transmit must wait until it detects a free token passing by.
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