SAN Switch

What is FLOGI PLOGI and PRLI In SAN Switch? This blog has a detail explanation of three device login processes on the SAN switch. Basically, there are three device login process FLOGI, PLOGI and PRLI.

What is Device Login In SAN Switch?

Device Login is a series of processes that happen when a new node or device is connected to a Fabric. Once Device Login Process Completes then a device can communicate with other devices in the same fabric. Its Involves three steps FLOGI PLOGI and PRLI.

Components of Device Login In SAN Switch

Host – These are the server which is connected to Switch.
Array – These are the storage Array connected to Switch.
SAN Switch – A SAN switch that has FC Ports.

A device login process happens for all devices that connect to a Fabric for the first time.

What is FLOGI Process in SAN Switch?

During the FLOGI process, a device sends its first frame to the SAN switch. The SAN switch assigns an FCID to the device and the end device confirms to the switch that it received an FCID. The switch uses this FCID to identify the end device connected to it in the SAN network.

FLOGI Process happens when a new device connects to SAN switch or fabric for the first time. The new devices send it the first frame to switch that contains information like WWPN and buffer to buffer credits (B2B credits).

What is PLOGI SAN Switch?

PLOGI Process has two steps, port initialization and registration in Name Server. During port initialization a host and switch exchange information like port type and port speed. SAN switch uses these information and negotiates with host.

During negotiation SAN switch will come to know whether the end device is a server or a storage by referencing the port type.

What is Name Server In SAN Switch?

During Name Server registration of PLOGI process the device register its information in the name server. This provides information to device about all other device which are registered in name server that it can communicate to.

Each fabric in the SAN switch network maintains a name server. This name server contains the information of every device connected to the SAN Fabric. Two devices in the SAN switch network can communicate only if both of them are in the name server.

What is Process Login (PRLI) In SAN Switch?

PRLI also stands for process Login. During this process, actual communication happens between two devices in SAN network. In simple terms, we can say that during PRLI, N_port communicates with another N_Port. In broad term a host communicates with storage array.

During the PRLI process, a host sends a PRLI request to a storage array. If proper SAN zoning and LUN masking exist then storage array accept the PRLI request and starts the communication between them.

Video Tutorial On Device Login Process SAN Switch

Watch the below video tutorial from YouTube explaining the device login process in SAN switch. Subscribe the channel for more such videos.

In this post, we will see the commands for the Cisco MDS SAN switch zoning. You can also do the zoning from GUI but using CLI would be much faster.

We suggest you should read the What Is Zoning for better understanding steps.

What Is Zoning?

Zoning is a process of grouping initiator and target ports WWPN which is performed in SAN switch. Once zoning is completed initiator and targets can exchange of FC packets happens between them.

We have already discussed the zoning steps for brocade SAN switch in previous posts.

Steps Of Cisco MDS SAN Switch Zoning

Below are the overall steps of Zoning that need to perform on a switch. We will discuss more on each step in the coming section.

1. Check Connectivity Status of HBA Port.
2. Create fcAlias Name For HBA Port WWPN
3. Create fcAlias for Storage Array Port WWPN.
4. Create a ZONE and add fcAlias members.
5. Add the newly created zone to an active zone set.
6. Commit the zone if extended zoneset is enabled.
7. Activate the zoneset.
8. Copy running-config to startup-config.

Cisco MDS SAN Switch Zoning Commands

First, we need to enter into the config mode. In the Cisco switch, all configuration changes happen in configuration mode.

To enter the config mode just execute the below command.

switch# config t

Step 1. Check the connectivity Status of Initiator

First, we need to check if the host is connected to the SAN switch or not. You can check it by executing below command

switch (config)# show fcns database | grep -i 10:xx:xx:xx:xx:xx:xx:xx

If you want to know how devices connect with each other in a SAN network then follow or post on SAN architecture.

Step 2. Create fcAlias

We need to create fcAlias for host WWPN. As a WWPN is difficult to remember so for better management creating fcAlias is good practice.

The below commands creates a fcAlias of host WWPN with the name HostName_hba1in VSAN 3.

switch(config)# fcalias name HostName_hba1 vsan 3
switch(config-fcalias)#
switch(config-fcalias)# member pwwn 10:00:00:23:45:67:89:ab
switch(config-fcalias)#exit
switch(config)# fcalias name Array_Port1 vsan 3
switch(config-fcalias)#
switch(config-fcalias)# member pwwn 50:00:00:53:29:67:89:ab
switch(config-fcalias)# exit
switch(config)#

Similarly, we can create fcAlias for Storage array port or any devices that are connected to SAN switch.

Step 3. Create a zone and add fcAlias Member

After creating fcAlias we need to create a zone in VSAN 3. After creating a zone we need to add fcAlias member into it.

Below commands will create a zone with name Zone1 in VSAN 3 and add two fcAlias member HostName_hba1 and Array_Port1.

switch(config)# zone name Zone1 vsan 3
switch(config-zone)#
switch(config-zone)# member fcalias HostName_hba1
switch(config-zone)# member fcalias Array_Port1
switch(config-zone)# exit
switch(config)#

Step 4. Find Active Zoneset and Zone and Activate it.

Every VSAN has an active zoneset. If a zone is not a part of active zoneset then communication between the zone’s member will not happen.

In the below example, ZoneSet3 is the active zoneset in VSAN 3. We need to add Zone1 in active zoneset ZoneSet3. Finally, we need to activate the zoneset again.

switch(config)# show zoneset active vsan 3
switch(config)# zoneset name ZoneSet3 vsan 3 
switch(config)# zoneset name ZoneSet3 vsan 3
switch(config-zoneset)#member Zone1
switch(config-zoneset)#zone commit vsan 3
switch(config)# zoneset activate ZoneSet3 vsan 3

Step 5. Save The Running Config To Start-Up Config

Finally, we have to copy the running-config to startup-config. This will make sure that even after reboot the zoning information is consistent.

switch(config)# copy running-config startup-config

Cisco MDS SAN Switch Zoning Video

You can also watch below video tutorial on the Cisco MDS SAN switch zoning. You can also subscribe to the Youtube Channel for more such videos.

In this post, we will discuss Zoning in the Brocade SAN switch. In addition to the definition, we will discuss the commands for zoning in the Brocade switch.

You can also refer to our post on Zoning in Cisco MDS Switch.

Important Terms Brocade SAN Switch Zoning

Lets first discuss some of the common terminologies that are used in Brocade Zoning.

What is WWPN?

WWPN stands for World Wide Port Name. Each port in the SAN network has a unique WWPN of a 64-bit address. In SAN network ports are identified by its WWPN. Below is an example of WWPN

Ex : 10:xx:xx:xx:xx:xx:xx:xx

You can refer to the post on types of FC ports.

What is FC Alias Name?

Alias Name In Brocade SAN Switch is the human-readable name of WWPN. WWPN is 64-bit addresses and difficult to remember. Hence a storage admin creates an alias name for WWPN.

What is Zone Brocade SAN Switch?

Zone in Brocade SAN Switch is nothing but a grouping of alias members. Zoning basically creates a secure path between two end devices for FC communication. These members are FC alias name of Host WWPN and Storage Array WWPN.

What is an Active Zone?

Active Zone Configuration in SAN Switch consists of active zones. It means if a zone is part of active zone config then only interaction happens between the zone members. In a fabric, only one zone config can be in an active state.

Prerequisite Of Brocade Zoning

Before we start zoning we must collect the necessary information. Below is the checklist you must collect before doing zoning.

• SSH Or GUI connectivity to Brocade SAN switch
• Server Name For Zoning
• WWPN  of Server HBA Port
• WWPN of Front End Storage Array Port

Steps Of Zoning in Brocade SAN Switch

Once we have the above information. Below are the steps we need to perform. These are the overall steps of zoning in the brocade switch. In the next section, we will about CLI commands for zoning.

1. Check Connectivity of HBA Port To Fabric.
2. Create FC Alias Name For HBA Port WWPN and Storage Array Port WWPN.
3. Create a ZONE and add alias members.
4. Add the zone to active configuration zone
5. Save the active configuration zone
6. Enable active configuration zone

The above step may differ if you have additional features such as Enhanced zoning in your Storage Area Network.

CLI Command for Brocade SAN Switch Zoning

You can also perform zoning via the command line. You need to use putty to connect to the SAN switch. Below are steps to perform on CLI to create zoning on the Brocade SAN switch.

1. Check Connectivity of HBA Port To Fabric.

nodefind 10:xx:xx:xx:xx:xx:xx:xx

2. Create FC Alias Name

alicreate “host1_hba1”,”10:xx:xx:xx:xx:xx:xx:xx”
alicreate “storage_hba1”,”50:xx:xx:xx:xx:xx:xx:xx”

3. Create a ZONE and add FC alias members.

zonecreate “zone1”, “host1_hba1; storage_hba1”

4. Add the zone to active config zone

Before we add the zone to the active config zone, we have to find it by executing the below command.

cfgactvshow | more

You can find the active config zone at the top of the output. Once you find it now you can add the zone into it.

cfgadd “activecfg1”,“zone1”

5. Save the active config zone

cfgsave

6. Enable active config zone

cfgenable “activecfg1“

Today’s Question on Zoning In Brocade SAN Switch

Now a tricky question for you guys. Do some research and let me know your answer in the comment section.

1. What is the purpose of cfgsave command?
2. What will happen if the cfgsave command is not executed?

Zoning is a common practice that a storage admin performs in day to day activities. It is a mandatory step that a SAN admin has to perform to allow an initiator to access storage devices.

In this post, we will see what is Zoning and why we need it. We will also discuss the types of zoning and difference between them.

A storage admin does zoning in SAN switches. The most popular and stable SAN switches are brocade and Cisco MDS. You can use the command line as well as GUI to do it.

What Are WWNN and WWPN?

WWNN stands for World Wide Node Name. It is a unique ID assigned to all FC devices in Storage Area Network. Due to its uniqueness, other FC devices use WWPN to identify a Node in the SAN network.

WWPN  stands for World Wide Port Name. Every device in a SAN network has FC ports. Let it be a storage device, host or SAN switches. These ports have a unique identification called WWPN.

WWPN and WWNN are the 64-bit address that is difficult to remember. Hence, a storage admin creates FC alias for easy reference. In the next section, we will discuss various types of alias in a SAN.

What Are fcalias, device-alias, and alias?

fcalias and device-alias are CISCO SAN switch terminology. The WWPN is hard to remember hence an alias name is created for WWPN. In some storage area networks instead of fcalias devices-alias are created.

The main difference between a fcalias and devices-alias is that a fcalias can communicate within a VSAN but devices-alias can communicate across VSANs.

Similarly, an alias is Brocade SAN switch terminology. We can use an alias name for WWPN. It is a 64bit address and unique to each vendor.

You can check out Brocade zoning and Cisco Zoning to know how to create an alias.

Why We Need Zoning?

Zoning provides a secure path between an initiator and a storage array. In a SAN network, many devices are connected to the same SAN switch. In order to make sure that the FC traffic flows between particular devices, we need to create zoning.

This also provides a flexible way to manage all devices in a Storage area network.

What Is Zoning?

Zoning is a grouping of initiator port and target ports. After this step, FC devices can send or receive FC frames from other devices in the SAN network. Zoning also increases the security as a flow of FC traffic happens between a particular initiator and target.

It involves 3 to 4 steps which are performed in a SAN Switch. You can use both CLI and GUI to do it. If you are a beginner then it always better to use GUI to avoid any human error.

Check out the YouTube Video for a detail explanation on this topic. You can even subscribe to the channel for more such videos.

What are the types of Zoning?

There are two types of Zoning, Hard, and Soft. In most infra, you will find soft zoning as it is easy to implement and manage. On the other hand, hard zoning is rare but it provides high security. Hence, you should use hard zoning if security is a high priority.

In the next section, we will discuss the difference between them.

Difference between Hard and Soft Zoning?

In Hard Zoning you need to add Domain ID and Port number of a Switch in a zone. While in soft-zoning, you need to add WWPN or fcalies are in the same zone.

For example, if the domain id of a switch 10 and a host is connected to port number 5 and storage device is on port 6. In this case, the zone you can create two fcalias with port numbers 10, 5 and 10,6. After that, you can add them to the same zone.

Now, if you swap the cable to different ports then the host will see disconnection. In order to fix it, you must do rezoning with the correct ports.

Hard Zoning is highly secure than soft. However, in most environments, the latter is preferred.

In the case of Hard Zoning any physical changes like cable swap, you have to do a rezoning. Now In the case of Soft Zoning, there is no need for any rezoning. So if you frequently perform maintenance activities on your switch then you should choose soft zoning instead of hard.

In this post, we will discuss basics of SAN switch. SAN switch is a vital hardware component of the Storage Area Network. If you are a storage admin then you must gain knowledge on various SAN switches.

Basics of SAN Switch What Is SAN Switch?

SAN Switch is an important hardware component fo SAN storage. SAN switch consists of FC Ports that physically connects a Host and Storage devices through FC cables.

A Group of SAN switch is called Fabric. The Storage Area Network has two fabric for redundancy. Popular vendors for SAN switch are Brocade and Cisco.

Types Of FC Ports In SAN Network

F_Port

F_Port is known as a fabric port. You can set up an FC port as an F port. This port always connects to N_Port via fiber cable.

N_Port

N Port is also called a node port which represents a storage port or host port. N_Port is always connected to the port that is configured as N Port.

E_Port

E port is an expansion port. We can use this port to connect one switch to another switch. This type of connectivity between two switches is also called Inter-Switch Link (ISL).

G_Port

This is a generic port that can operate as either an E_Port or a F_Port. It means if the end port is an F port then G Port will act as N Port. Similarly, if the end port is an E port then it will act as E Port.

The architecture of SAN Network

The below diagram shows a simple architecture of the Storage Area Network. This picture also shows the various types of FC ports that we have discussed in the previous section.

Complex Architecture of SAN Network.

The below diagram shows the complex connectivity of the SAN switch in a SAN network. This diagram has multiple hosts and redundant fabrics. Additionally, it has multiple storage and host connected to the SAN switch.

If the above diagramme confuses you then watch the below YouTube video for more clarity. This video explains the basics of SAN switch in a simpler way.