Cabletron Systems 9A128-01 manual Connection Policy

FDDI Management

Connection Policy

!

CAUTION

The SMT Connection Policy determines which types of connections are allowed among the four FDDI port types: A, B, M (Master), and S (Slave). FDDI protocol forbids Master—>Master connections; all other connection types are legal, although some are considered to be undesirable.

The Connection Policy window, Figure 4-3, lists potential connection types in a “Reject X-Y” format, where X represents the FDDI port on the selected module, and Y represents the attaching node. An X in the checkbox next to a Connection Policy indicates that the connection has been disallowed.

Figure 4-3. The Connection Policy Window

The following table summarizes the FDDI connection rules:

Table 4-1. FDDI Connection Rules

	A	B	S	M
A	V, U	V	V, U	V, P
B	V	V, U	V, U	V, P
S	V, U	V, U	V	V
M	V	V	V	X

V—valid connection X —illegal connection

U —undesirable (but legal) connection; this requires that SMT is notified. P —valid, but when both A and B are connected to M ports (a dual-homing

configuration), only the B connection is used.

Though technically legal under FDDI connection rules, undesirable connections will cause a twisted or wrapped ring.

4-6 Connection Policy