About SAN Switches | Fiber switch | Fibre channel

Fibre Channel Switch

Brief Introduction

In the computer storage field, a Fibre Channel switch is a network switch compatible with the Fibre Channel (FC) protocol. The host will access the read\write operation from the storage through the switch. In detailed, the host & Storage is connected to the switch.

A Fibre Channel switch is designed for high performance, low latency,high availability and lossless data transmission. Director-class FC switches can add additional capabilities such as zoning to disable unwanted traffic.


Fibre Channel switches may be deployed one at a time or in larger multi-switch configurations. SAN administrators typically add new switches as their server and storage needs grow, connecting switches together via fiber optic cable using the standard device ports.
SAN_Connectivity
SAN Connectivity

Switch Topology

1. Core edge Topology

2. Edge core Topology

3. Mesh Topology


1. Core Edge Technology

This SAN configuration utilizes a large switch at the core of the fabric to which storage arrays are connected. Hosts are attached to smaller port count 'edge' switches, which are attached to the core switch via ISLs. This topology can grow to hundreds of ports while ensuring that hosts only have to traverse two switches to access their storage. Hosts that require lower latency or higher throughput can be connected directly to the core switch.

2. Edge Core Technology

The edge-core topology positions storage (targets) on the core tier and initiators (servers) on the edge tier. As the storage and servers are on completely different switches, this topology provides easy administration and also good performance, with the majority of the traffic just traversing one hop from the edge to the core. The key drawback of this design is that the core connections and the storage are in contention for extension. This means that this topology provides only minimum growth.

3. Mesh Topology

In a mesh SAN, every switch in the fabric is connected to every other switch by way of an inter-switch link (ISL). In such a configuration a host will traverse a maximum of one ISL to access its storage. When configuring a mesh SAN it is favorable to group hosts and their storage on the same switch to cut down the amount of traffic on the ISLs. As a mesh grows, the number of ISLs on a single switch grows at the rate of one for every additional switch. After a certain point there is minimal benefit gained by adding extra switches as many of the additional ports will be required for ISLs.


There are so many vendors in the market who manufacturers the FC switches. Major Vendors like below
Brocade
Cisco
Mc-data

Any vendor's switch will starts with 8 ports, 16 ports, 24 ports and 48 ports. 8 ports will come like a socket which can easily insert on a switch and every port is a licensed one. If we want to procure a 8 ports socket we have to contact to the switch vendor and have to buy the ports with license. These task will be taken care by your respective sales team.

The rate of data transfer in a switch is 8 GB/sec at max, if we need to increase the speed we have to do the trunking/ISL. We can also change the port speed to 2, 4, 8 Gb/sec & auto mode.

Directors switch offers a high port-count in a modular (slot-based) chassis with no single point of failure (high availability).

Switches are typically smaller, fixed-configuration (sometimes semi-modular), less redundant devices.

Front_view_of_a_Switch
Front view of a Switch




Rear_view_of_a_switch
Rear view of a Switch


In a switch the major activity will be the Zoning and also we do trouble shooting, ISL, Port Channeling and other works.

Zoning means “Grouping of Host HBA WWPN and Storage Front End Ports WWPN to speak each other.”

Zoning_Structure
Zoning Structure



Types of Zoning:

1. Soft Zoning
2. Hard Zoning
3. Mixed Zoning

 Soft Zoning: 

It uses the Server HBA WWN number and Storage Front End Port WWN number. It’s also known as WWN Zoning. A major advantage of WWN Zoning is its flexibility. It allows the SAN to be recabled without re configuring the Zone information.



Physcial_connectivity_between_server_and_storage
Physical Cabling between Server ,Switch and Storage with Single Path


Physcial_connectivity_between_server_and_storage
Physical Cabling between Server ,Switch and Storage with Multipath

Hard Zoning: 

It uses the Server and Storage physical ports connected on a FC switch. It’s also known as Port Zoning. A major disadvantage is any change in the fabric configuration affects zoning database.

Mixed Zoning: 

It combines the qualities of both WWN zoning and port zoning.

Below are the models for your reference
 

Brocade: 

Switches: 6510, 6505, 5300, 5100, VA-40FC, 5000, 4900, 2400, 2800, 3800, 3900, 4100, 300, 200E

Directors: DCX 8510-8, DCX 8510-4, DCX, DCX-4S, 48000, 24000, 12000

Cisco:

Switches: Cisco MDS 9020, 9120, 9124, 9124e, 9134, 9140, 9148, 9216, 9216A, 9216i, 9222i, and 9250i

Directors: Cisco MDS 9506, 9509, 9513, and 9710

Mc-Data:

Switches: 3232, 4500, 4700

Directors: 6064, 6140, 10000




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2 comments

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March 30, 2016 at 9:59 AM delete

You are Awesome Shaik Mehboob and very help full to understand the concept.
Could you add some basic troubleshooting with EMC and HP Eva storage

Thanks in Advance
Dev Mishra

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April 1, 2016 at 11:00 AM delete

Hello Mishra,

Thanks for your valuable comment. From April 4th onwards you can able to view the EMC VMAX articles in sanadmin.net site. HP EVA is in under review.. will let you know once it updated.

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