D-Link DGS-3100 user manual Dividing Stacks

DGS-3100 Series Gigabit Stackable Managed Switch User Manual

Unit ID 1, and serving as the stack Backup master, while the already running stacking member with Unit ID 2 remains the active Stack Master.

•The Stack Master performs Unit ID Allocation and Conflict Resolution process.

–If the new stacking member is in the Factory Default mode, the new stacking member is assigned the lowest available Unit ID by the Stack Master. It is strongly recommended that Auto Assign mode is used to assign the Unit ID. The Auto Assign mode provides better stack resiliency.

–If the new stacking member already has an assigned Unit ID, and that Unit ID is unused in the current stack, the incoming stacking member is assigned Unit ID. The Stack Master applies any device configuration to the new stacking member.

–If the new stacking member already has an assigned Unit ID, and that UnitID conflicts with an existing Unit ID the Stack Master reallocates a new Unit ID to the new stacking member. The lowest available Unit ID is applied to the new stacking member. This occurs only if new stacking member does not have a manually assigned Unit ID, which the Stack Master cannot change.

–If the new stacking member cannot be assigned an available Unit ID, then the new stacking member is effectively shut down and cannot join stack. For example, if stacking member replacement that can only occur if the new stacking member has a manually assigned Unit ID.

•The Stack Master performs Unit and Stacking Port Configuration for the new stacking member.

•Any configuration information the Stack Master retains that is relevant to the Unit ID of the new stacking member is applied. If the new stacking member was assigned the same Unit ID of the replaced stacking member, then the new stacking member receives the same switch configuration as the failed stacking member, described in Replacing Failed Stacking-Members in a Running Stack.

Dividing Stacks

This example assumes that a working stack is divided into two groups. The stack is divided either by a failed stacking link connected to two stacking members in the stack or by a failed stacking members in a chain topology which causes disconnection between two units in the stack. In this case we should consider each sub-group as an independent running stack configuration. For each sub-group we should consider three sub options:

•Both the Stack Master and the Backup Master are part of the sub-group.

•Either the Stack Master or the Backup Master is part of the sub-group.

•Neither the Stack Master nor the Backup Master is part of the sub-group.

When a stack is split into two parts, the following occurs in each partial stack according to the following scenario: Both the Stack Master and the Backup Master are part of the sub-group.

Nothing changes, except the Stack Master recognizes the missing stacking members as removed stacking members and routes traffic around them.

Since both the Stack Master and Backup Master are in this stacking section, this section is operating and the other section cannot operate.

The following occurs when the stack is divided and both the Master and Backup master are in the sub-group:

•The Master Discovery, Master Election and Unit ID Allocation & Duplicate Unit ID Conflict Resolution processes are performed, resulting in the following:

–Any configuration information stored by Stack Master, which remained in the group, that is relevant to the stacking members remains unchanged.

–Topology information, inter-stacking member forwarding information for transmitting traffic to any other stacking member, managed by the Stack Master includes only stacking members that remain connected after the stack is divided.

–The divided stack continues to operates normally, the only difference is there are less stacking members than prior to the stack division.

–No Unit ID changes are performed in each divided stack.

–The Stack Master notifies the system administrator using SYSLOG messages and SNMP traps of the removed stacking members. In addition the Stack Master also notifies the system administrator whichd ports belong to unreachable stacking members and are reported as Not Present.

•Either the Stack Master or the Backup Master remain in the divided group

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