CISCO fabrics -MDS-1

Important terms to understand.

Fabric Manger  is a  single tool used to configure ,monitor and manage an entire fabric of switches,directors .With in fabric manager,an overview of the fabric and its topology can be obtained.

Device manager  is used to manage an individual switch/director including the installed switching modules,the supervisor modules ,the status of each port within each module,the power supplies and the fan assemblies. While fabric manager tables show values for one more switches ,device manager just can show values for single switch.

VSAN

Physical topology is divided into logical fabrics called VSANs.Zoning is assigned per VSAN.Switch ports are assigned to only one VSAN.By default all switch ports are assigned to VSAN 1.(One physical switch to be carved into several virtual fabrics).Default VSAN;VSAN 1 cant be deleted however it can be suspended

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Isolated VSAN:

VSAN 4096 is the isolated VSAN.All non trunking ports are transferred to this VSAN when the VSAN to which they belong to is deleted. This avoids an implicit transfer of posts to the default VSAN or to another configured VSAN.

Domain Parameters:

The fcdomain feature performs principal switch selection ,domain id distribution ,FCID allocation and fabric reconfiguration function as described in the FC-SW2 standards.The domains are configured on a per VSAN basis.When a switch boots up or joins a new fabric, it can request a specific domain ID or take any available domain ID.The configured domain ID can be preffered or static .Bydefault the configured domain is 0 and the configured type is preferred. If a domain ID is not configured, the local switch sends a random ID in its request. If the configured type is preferred, the local switch accepts the domain ID assigned by the principal switch and the assigned domain ID becomes the runtime domain ID.If the configured type is static ,the assigned domain ID is discarded, all local interfaces are isolated and the local switch assigns itself the configured domain ID which becomes the runtime domain ID.After obtaining the domain ID from the principal switch in the VSAN, the local switch assigns Fibre Channel Identifiers (FC IDs) to each end device as they log into the fabric. This process is known as FLOGI.Domain ID uniquely identify a switch in VSAN.A switch may have different domain IDs in different VSANs. The domain ID is part of over all FCID.

Set switch priority:

By default ,the configured priority is 128.The valid range is between 1 and 254.Priority 1 has the highest Priority. Value 255 is accepted from other switches but cannot be locally configured. Any new switch can become the principal switch when it joins a stable fabric. During  the principal switch selection phase, the switch with highest priority becomes the principal switch. If two switches have same configured priority, the switch with lowest WWN becomes the principal switch.

Name server:

The nameserver  functionality maintains a database containing  the attributes for all hosts and storage devices in each VSAN.

G_port or generic port on a switch can operate as an E_port or F_port. Found on Brocade, McData, and QLogic switches.

N_port is a port on the node (e.g. host or storage device) used with both FC-P2P or FC-SW topologies. Also known as node port.
E_port-The port can be either a trunking or non trunking port depending on the trunking mode port mode.E port is used when the port talks to another port of different switch forming an ISL.