Specifications

TOKEN RING DEVICES AND APPLICATIONS

3-2

Figure 3-1. MMACs

Concentrators

Modular concentrators install in the MMAC and provide multi-station

access to the main Token Ring network through lobe cabling connected at

Trunk Coupling Unit (TCU) ports. These devices provide multiple TCU

(or lobe) ports. A TRMIM-24A, for example, is a concentrator that installs

within an MMAC and provides twenty-four lobe ports that connect to the

MMAC’s Flexible Network Bus (FNB). A TRXMIM-24A, for example,

provides the same functionality as a TRMIM-24A, except that it allows

individual ports on the same MIM to be assigned to different rings.

Cabletron Systems also provides standalone concentrators, such as the

TRXI series of active and passive intelligent concentrators. Other

standalone concentrators, such as those included in the MicroMMAC-T

series of intelligent hubs and the STH series of intelligent and

non-intelligent hubs, for example, are “stackable” and allow additional

concentrators to be attached and thus act as one logical concentrator.

Ring In/Ring Out (RI/RO) Devices

Ring In/Ring Out (RI/RO) ports provide externally accessible trunk

connections. Use of these ports allow you to extend the ring by connecting

to RI/RO ports on different Token Ring devices. The TRRMIM-4AT, for

example, has a set of user-conﬁgurable RI/RO ports, which provide trunk

port links to the MMAC in which it is installed. Connecting these RI/RO

ports to RI/RO ports on another hub joins these hubs on a single ring.

MMAC-M8FNBMMAC-M5FNB

MMAC-M3FNB

MIM Slots MIM Slots

MIM Slots

Management Slot