Avaya Configuring Ethernet, FDDI, and Token Ring Services Bedienungsanleitung PDF herunterladen (Seite 61)

Configuring FDDI Services

308623-14.00 Rev 00

3-19

Editing FDDI Path Attributes

FDDI nodes exchange frames using the Timed-Token Protocol (TTP). The TTP

defines how the token target rotation time (TTRT) is set, the length of time a node

can hold the token, and how a node initializes the ring.

Each node is responsible for monitoring the integrity of the ring. By using a

minimum valid transmission timer (TVX), nodes can detect a break in ring

activity. If the interval between token receptions exceeds the value of the TVX, the

node reports an error condition and initiates the claim process to restore ring

operation.

The TTRT carried in claim frames issued by the FDDI station are known as path

attributes. Figure 3-2

illustrates their relationship.

Figure 3-2. Range of Values for FDDI Path Attributes

You can set FDDI path attributes by:

• Specifying the minimum TVX

• Specifying the maximum TTRT

• Specifying the requested TTRT

0 ms 2.5 ms 1336.9344 ms

TVX

lower

bound

T_Max lower bound

Requested TTRT

LS0015A

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Avaya Configuring Ethernet, FDDI, and Token Ring Services Bedienungsanleitung Seite 61