958-000283-003, March 2005)

Table Of Contents

Edge Switch 2/24 installation guide 49

Fabric parameters

Configure the following parameters as required by your fabric.

R_A_TOV

Configure resource allocation time-out value (R_A_TOV) in tenth-of-a-second increments. This

variable works with the error detect time-out value (E_D_TOV) variable to control the switch’s

behavior when an error condition occurs. Resources are allocated to a circuit when errors are

detected and are not released for reuse until the time set by the R_A_TOV value expires. The default

value is 100 tenths (10 seconds). Set a value between 10 tenths and 1200 tenths (1 through 120

seconds).

NOTE: Set the same value for R_A_TOV on all directors and switches in a multiswitch fabric. If the

value is not the same on all units, the fabric segments. Also, the value for R_A_TOV must be greater

than the value configured for E_D_TOV.

E_D_TOV

Adjust the E_D_TOV in tenth-of-a-second increments. An error condition occurs when an expected

response is not received within the time limit set by this value. The default value is 20 tenths (2

seconds). Set a value between 2 tenths through 600 tenths (.2 through 60 seconds).

NOTE: Set the same value for E_D_TOV on all switches and directors in a multiswitch fabric. If the

value is not the same, the fabric segments. Also, the value for E_D_TOV must be less than the value

configured for R_A_TOV.

Switch priority

Setting this value determines the principal switch for the multiswitch fabric. Select Principal (highest

priority), Default, or Never Principal (lowest priority) from the Switch Priority drop-down list.

Setting these priority values determines the principal switch selected for the multiswitch fabric. For

example, if you have three switches in the fabric and set one as Principal, one as Default, and one

as Never Principal, the unit set to Principal becomes the principal switch in the fabric.

If all switches are set to Principal or Default, the switch with the highest priority and the lowest

WWN becomes the principal switch. Following are some examples of principal switch selection

when switches have these settings:

• If you have three switches and set all to Default, the switch with the lowest WWN becomes the

principal switch.

• If you have three switches and set two to Principal and one to Default, the switch with the

Principal setting that has the lowest WWN becomes the principal switch.

• If you have three switches and set two to Default and one to Never Principal, the switch with the

Default setting and the lowest WWN becomes the principal switch.