Fibre Channel Data link layer

Hi,
My professor is giving me a hard time by asking to explain the FC data link layer in detail (addressing etc). Please help me.
Thanks!

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Similar Messages

Data Link Layer

Hi, I am bit confused in Data Link Layer. When a sender machine send a data to Reciever machine then it starts from App--Pres--Sess--Transp---Network---Data??? I have understood all upper 5 layer function but in the Network layer the packet has information of Soure and Destination Address then why it needs to have MAC address. Please answer me in details. Thanks

The Network Layer header hast the Source and Destination Address (IP address) of the sender and the end receiver. The Data Link header has the Source and Destination address (MAC address) of the sender and the following device in the path to reach the sender.
The sender know where it wants to go (Destination IP address), to reach that destination it has to reach the next device in the path and for that it needs the Destination MAC address of that device... once the packet is in that second device (and it still knows where it wants to go (Destination IP address), now it has a new source MAC address and a new destination MAC address because it wants to get to the next device (may be router 2)... once it gets to router 2 (and it still knows where it wants to go) the packet (in its data link header) now has a new MAC Address in its source and destination.... finaly it gets to the last device and it knows that the Destination IP is in its LAN.
Data link header helps the frame to make it to the next device.... Network Layer header helps you to reach the final destination through all the devices.
Hope it is not so confusing.
Rate this if it was helpful.

IPv6 and data link layer

As we have learned, layer design is made to make us and Vendors happy about new inventions on a network field. If so, how come up this statement:
The following data links are supported for IPv6:
ATM permanent virtual circuit (PVC) and ATM LANE,
Ethernet, Fast Ethernet, Gigabit Ethernet,
FDDI,
Frame Relay PVC,
Cisco High-Level Data Link Control (HDLC),
PPP over Packet over SONET (PoS),
ISDN, serial interfaces
dynamic packet transport (DPT).
Is this truth that IPv6 (L3) is connected to lower layer (layer 2)?
Best Regards,
Tirke

> Is this truth that IPv6 (L3) is connected to lower layer (layer 2)?
Well, they have to be, or you couldn't send layer 3 IP packets over the layer 2 links. In IPv4 the connection between layer 3 (IP) and layer 2 (say, ethernet) is most often via the Address Resolution Protocol, layer 2 ethernet type 0x0806 (IPv4 being 0x0800 and IPv6 0x86dd).
In IPv6 the connection is instead via the ICMPv6 neighbor discovery protocol. Neighbor discovery was invented with goals like getting more uniformity into the layer 3->2 transition over different link types, and better duplicate and dead address detection.
-- Jim Leinweber, WI State Lab of Hygiene

Can I just send the data to NIC's buffer in LV? (how to access data link layer?)

Now, I need to send something over network, yet those are not packed in TCP/IP or IPX packet, them are just some data a device can understand.
So the problem I met is seems I cann't send the data into NIC's buffer(I can do that in C, yet I want to use LabVIEW to do that)
And I don't want to do that by using a CIN, every time the program call or exit the CIN,there will be a delay, it's would bring me a bad impace to my application.
So is there anyone can help me with that? I really need some master can give me a comfirm!

I'm not an expert on network communication, so maybe you can explain how data can travel on an IP based network without being wrapped in some packets from a protocol like TCP or UDP? Maybe it's possible for LabVIEW to do what you want, or maybe compiling your C code into a DLL (no need for a CIN) and calling that will be fast enough for what you want.
In any case, I think I can answer one question:
So, how long would we have to expect LV add/improve these functions? Could it be in next minor update?
Not likely, nor is it likely to be in any other version soon. LabVIEW is not built to handle this sort of thing any more than PHP or perl are and I don't think NI will change it to be able to do so. For that you have C, which you can call through a DLL. Some DLLs are supported on RT targets as well, but I'm not sure what the criteria are. They are probably listed somewhere on this site.
I assume that calling a DLL in an RT target will hurt your determinism, but communication code should not be time-critical code, unless your application is an application which requires high speed data transfers and synchronization between different nodes.
Try to take over the world!

Xserve Raid will not mount - fibre channel link down

I came back from being out of town and my Xserve is running, but will not mount on the G5 tower via fibre channel. It was powered off and up again and still nothing. Apple tech says to reset raid controllers, however, I have sensitive data on the drives and lots of video/FCP projects on there. It has just run out of warranty and now asked to pay $199 per incident to get any help. I will gladly take any help.
Read the boards, ran Disk Utility and still did not show up.
Also, told the fibre cables tend to "burn out" but have yet to spend money if this is not the problem.
Thanks.

Resetting the controllers is non-destructive. However, if you power-cycled the array, that should take care of it.
told the fibre cables tend to "burn out"
I've never experienced (or heard of this) myself, and have never had a problem on any of my arrays, some of which have been running for years with zero problems. Of course, environment (especially heat) could play a part, but it seems a little bit of a stretch to me.
Does RAID Admin have anything to say about the RAID?

Cisco TrustSec Fibre Channel Link Encryption performance?

Hello,
could anybody provide me some more details about Cisco TrustSec Fibre Channel Link Encryption? We are thinking to invest in this feature. Can I really use all 32 FC Ports @ 8Gbit wire speed on the 3Gen Cards? Have somebody used this feature already?
Many Thanks in advanced!
gk

In my experience the auto connect never works properly with certain vendor products. Try hard setting your link speed, i.e. 2G or 4G depending on your HBA capabilities and the target device.

Fibre Channel Link light off on Xserve

I noticed a few days ago that the lower Fibre Channel link light and Activity lights are no longer working on the lower unit on my Xserve. So far I tried unplugging and replugging the Fibre cable but that didn't help.
THere are no warning lights lit on the Fibre card on the back of my G5, and from flipping through the Xserve manual, it looks like all those lights are correct also.
We recently had the network rewired and since then I haven't been able to access the RAID Admin to see what's up. I may have to reset the controller though.
If you have any advice on where to start troubleshooting, or settings to check once I get the RAID Admin working I'd appreciate the advice, thanks!
PS: I have installed the Xserve Driver Update 1.0

Everything seems to be working normally. I'm mastering off the few projects I just finished, and I'm able to play back to streams of Uncompressed 10 bit SD so far so good. Although the one working channel seems to be working a bit harder than usual
The Xserve RAID is hooked directly to my powermac G5 via Apple's Fibre Channel Card. I talked to my boss who has been working wit the network people and said the IP address should be the same, and it should be picking up DHCP. From your post it sounded like there may be a setting in RAID Admin for this? I'll check after I finish Edit to Tape
Think of my calmness this way: If the front of your car is hanging off the edge of a cliff, the last thing you'd want to do is make any sudden moves!

Need docs that explain Fibre Channel setup, getting I/O error on 2540 SAN

Sun T5220 Host running Solaris 10 5/09 as management host.
Qlogic 5602 FC Switch
Sun Storagetek 2540 - one controller tray with 9 300G SAS Hitachi drives. Firmware 7.35.x.
Sun branded Qlogic QLE2462 HBAs - PCI express, dual port. 3 in the T5220. qlcxxxx drivers for the HBAs.
Sun Common Array Manager software version 6.5.
I am a long-time Oracle DBA who has the task of setting up a Fibre Channel SAN. I am not a Solaris sysadmin, but have installed and maintained large databases on Solaris boxes where I had access to a competent sysadmin. I am at a classified site and cannot bring out electronic files with logs, configuration info, etc. to upload. Connecting the T5220 is the 1st box of many. This is my first exposure to HBA's, Fibre Channel, and SAN, so everything I know about it I have read in a manual or from a post somewhere. I understand the big picture and I have the SAN configured with 2 storage pools each with 1 volume in them on RAID5 virtual disks. I can see the LUN 0 on the T5220 server when I do a luxadm probe and when I do a format. I formatted one of the volumes successfully. Now I attempt to issue:
newfs /dev/rdsk/device_name_from_output_of_luxadm_probe
I get an immediate I/O error. I could be doing something totally naive or have a larger problem - this is where I get lost and the documentation becomes less detailed.
What would be great is if anyone knows of a detailed writeup that would match what I'm doing or a good off-the-shelf textbook that covers all of this or anything close. I continue to search for something to bridge my lack of knowledge in this area. I am unclear about the initiators and targets beyond the fundamental definitions. I have used the CAM 6.5 software to define the initiators that it discovered. I have mapped the Sun host into a host group also. I do not know what role the Qlogic 5602 Fibre Channel switch plays with respect to initiators and targets or if it has any role at all. Is it just a "pass through" and the ports on the 5602 do not have to be included? Maybe I don't have the SAN volume available in read/write. I find bits and pieces in blogs and forums, but nothing that puts it all together. I also find that many of the notes on the web are not accurate.
This all may appear simplistic to someone who works with it a lot and if you know of an obvious reference I should be using, a link or reply would be greatly appreciated as I continue to Google for information.

Thanks for the reply. I had previously read the CAM 6.5 manual and have all the SAN configuration and mappings. Yesterday I was back at the site and was able to place a UFS filesystem on the exposed SAN LUN which was 0. I've not seen any reference to LUN 0 being a placeholder for the 2540 setup and when I assigned it, I allowed the CAM 6.5 software to choose "Next Available" LUN and it chose 0. LUN 31 on the 2540 is the "Access" LUN that is assigned automatically - perhaps it is taking the place of what you describe as the LUN 0 placeholder.
I was able to put a new UFS filesystem on LUN 0 (newfs), mount it, and copy data to it. The disk naming convention that Solaris shows for the SAN disks is pretty wild and I usually have to reference a Solaris book on the standard scsi disk name formats. My question/confusion at the moment is that I have 3 Sun branded Qlogic HBA's in the Sun T5220 server - QLE2462 (dual port) with one port on two of the HBAs cabled to the Qlogic 5602 FC switch which is cabled to the A and B controller of the SAN 2540 - there are only 2 cables coming out of the 5220; the 3rd HBA (for future use) has no cables to it. Both ports show up as active and connected on the server down to the SAN and the CAM 6.5 software automatically identified both initiators (ports) on the Sun 5220 when I mapped them. I had previously mapped them to the Sun host, mapped the host to a host_group, virtual disks to volumes, volumes to....etc.; and was able to put data on the exposed volume named dev_vol1 which is a RAID5 virtual disk on the SAN.
When I use the format command on Solaris, it shows two disks and I assumed this represented the two ports from the same host 5220. I was able to put a label on one of these disks (dev_vol1), format it, and put data on it as noted above. When I select the other disk in the format menu, it is not formatted, won't allow me to put a label on it (I/O error) and I can go no further from there. The CAM 6.5 docs stop after they get you through the mapping and getting a LUN exposed. I continue on the in a Solaris-centric mindset and try to do the normal label, format, newfs, mount routine and it works for the one "disk" that format finds but not for the other. The information from the format info on both the disks shows them as 1.09 TB and that is the only volume mapped right now from the SAN so I know it is the same SAN volume. It does not make sense that I would label it and format it again anyway, but is this what I am supposed to see - two disks (because of 2 ports?) and the ability to access it through one. I found out by trial an error that I could label, format, and access the one. I did not do it from knowledge or looking at the information presented....I just guessed through it.
I have not "bound" the 2 or HBAs in any way and that is on my list as next because I want to do multipathing and failover - just starting to read that so I may be using the wrong language. But I am wondering before I go on to that, if I am leaving something undone in the configuration that is going to hamper my success in the multipathing - since I cannot do anything with the 2nd "disk" that has been exposed to Solaris from the SAN. I thought, after I labeled, formatted and put a filesystem on the one "disk" I can write to that the other "disk" that shows up would just be another path to the same data via a 2nd initiator. Just writing that does not sound right, but I am trying to convey my thoughts as to what I logically expected to see. Maybe the question should be why am I seeing that 2nd "disk" in a Solaris format listing at all? I have not rebooted any time during this process also and can easily do that and will today.

Clarification on how to use Xserve Raid and Fibre Channel without xsan.

First let me apologize for not responding earlier to your response, I tend to get busy and then forget to check back here.
Tod, the answer to your question is No, only one computer is accessing the xserve raid files at any one time and that is via Fibre Channel. However I do have the xserve raids set up as share points via ethernet.
Maybe I should turn that off and only access the files with the one computer that can connect via fibre channel.
I never thought of that. I will try that while I await for your answer, thanks again.
Todd Buhmiller
I have the following setup:
Xserve: 2x2Ghz Dual Core Intel Xeon, 5Gb of Ram, Running 10.5.8 Leopard Server
Xserve Raid with firmware version 1.5.1/1.51c on both controllers, and
Qlogic Sanbox 5600
Apple Fibre Channel Cards in Xserve, and Mac Pro Tower; Apple 2 Port 4Gbs Fibre Channel Card
Mac Pro Tower-Quad Core Intel Xeon 2.8Ghz, 16Gb of Ram, Running Snow Leopard 10.6.4
Here is the problem.
The directory for the xserve raids keep getting corrup, and I use disc warrior to rebuild them. Is there a way to keep the directories from getting corrupt? I am a few pieces of equipment before I can build an Xsan as that is the ultimate goal, but until then, I just need to be able to have the raids funciton as storage without having to rebuild the directories all of the time.
Anybody have any suggestions?
Thanks
Todd Buhmiller
Widescreen Media
Calgary, Alberta Canada
Tod Kuykendall
Posts: 1,237
From: San Diego
Registered: Oct 11, 2000
Re: Xserve Raid Mounts, Corrupt Directory tired of rebuilding directory
Posted: Jun 27, 2010 1:25 PM in response to: Todd Buhmiller
Are multiple computers accessing the same data on the RAID at the same time?
If so then NO. This is the source of your data corruption and I'm surprised if you were able to get all your data back every time if this is how you've been running your system. Each fibre channel assumes it has full and sole control of every volume it has mounted, no data arbitration is practiced and data corruption will occur if this assumption is wrong.
The only way this set-up will work is to use partitions or LUN masks so the volumes are accessed by one computer at any time. As long as one computer relinquishes control before another mounts it you will dodge arbitration issues but this is a dangerous game. If you screw up and mount an already mounted volume - and there is no easy way to tell if a volume is mounted - corruption will then occur. Sharing data simultaneous at fibre speeds is what XSAN does and to do this you need it.
HTH,
=Tod
Intel Xserve, G5 XServes, XRAID, Promise

+The xserve raids will mount automatically to any computer that I connect the qlogic fc switch to+
This is source of the corruption to your data. Any computer that attaches to a drive/partition via fibre channel assumes that it alone is in control of the drive and data corruption is inevitable.
+Is that the issue, should I disconnect the xserve from the fc switch and leave it connected via ethernet?+
Short answer: YES. The ethernet connections are fine because the server is controlling the file arbitration through the sharing protocol. Fibre channel connections assumes complete control over the partition and no arbitration of the file access is performed. It's like two people independently driving trying to drive the same car to different locations.
Depending on your set-up it is possible for the two machines to see and use different parts of the Xserve RAID storage but they cannot access the same areas without SAN doing the arbitration.
Hope that's clear,
=Tod

OSX 10.5.6 doesn't see Fibre Channel Disk array, neither does Disk Utility

My system is a Power Mac G5 Quad, 6gb Ram, 1Tb internal hard drives, 1Tb external and several portable drives as needed.
The Drive array in question is a Fujitsu GR710 which contains 12 Seagate Cheeta ST336605FC drives which are around 35gb each.
OK, I have been given a Fibre Channel system, that at one time worked with OSX. I had to move it and now it doesn't show up on Disk Utility anymore. I can totally reformat it if possible, but I have to be able to see it first.
System Profiler sees the setup as:
Fibre Channel Domain 0:
Vendor: LSILogic
Product: LSI7202EP
Revision: Firmware 1.2.18.0, Fcode 1.00.37
Bus: PCI
Slot: SLOT-2
Initiator Identifier: 126
Node World Wide Name: 20:00:00:06:2B:12:C4:C4
Port World Wide Name: 10:00:00:06:2B:12:C4:C4
Address Identifier: 00:00:E8
Description: Port 0
Speed: Automatic (1 Gigabit)
Topology: Automatic (Arbitrated Loop)
Status: Link Established
Cable Type: Fiber Optic
SCSI Target Device @ 0:
Node World Wide Name: 20:00:00:E0:00:41:04:6D
Port World Wide Name: 21:00:00:E0:00:41:04:6D
Address Identifier: 00:00:EF
SCSI Target Identifier: 0
SCSI Peripheral Device Type: 0
Manufacturer: FUJITSU
Model: GR710
Revision: 0000
SCSI Logical Unit @ 0:
SCSI Logical Unit Number: 0
Manufacturer: FUJITSU
Model: GR710
Revision: 0000
Fiber Channel Preferences shows that a link is established.
Hardware RAID says that there is no hardware present.
I am using the Apple MA900A/G Fibre Channel Card to hook into the Drive array. It is hooked up with both ethernet and fiber optic cables.
I have used an IP scanner to search for the IP of the array and only find one that I can't identify at 224.0.0.251 another scan reports an IP of 0.0.0.0, neither worked when I tried to use Safari to access it.
I have tried several programs to try and get into this array and nothing sees it. All my experts tell me that I will need to use the Terminal program and use command lines to access the drives, but I can't find any information about what to do there. I've been told I need the driver for the array, naturally there isn't a driver for Mac to be had, but there are drivers for solaris, Unix, and windows. The last expert said to use the Unix driver, but I don't know where to put it in the system.
So I need help, Terminal commands to talk to the drive and revive it hopefully, or a system program that will do something similar. None of my diagnostic programs sees the array. The Card came with no software or instructions. Neither did the array. I haven't been able to find any hardware information about the drive from FuJitsu at all, it's too old for them to bother with anymore.
Any help would be greatly appreciated!
Thanks
Doc

I have to go with William on this one - if it's shows up over fibre then it should be okay. Have you gotten the admin module to see the device over ether? I have a feeling that is you can get the software to see it you might be able to configure the device into something the computer could mount.
The Promise that way - you can configure the device entire from the web interface and you don't need fibre communication working for any of the configuration of what RAID you want and which disks are attached with what set etc. Once the RAIDs are configured into volumes then the Xserve sees they exist and you can use Disk Utility to format them. If you don't need fibre communication I don't see how SCSI drivers would matter over ethernet. But maybe the box is a strange beast - odder things have been made.
Barring that - can you attach the device to an older machine with the drivers and configure the device into raw volumes and then an HFS+ (or whatever you want) system? If you did that and then switched the box back to Xserve it should be able to pick up the configured volumes drivers or no.
My $.02,
=Tod

Oracle Data Access Layer - w/Enterprise Services

I'm looking for an example Oracle Data Access layer incorporating Enterprise Services with at least a simple window form inserting and updating data tables.
Can somepoint point me in the right direction?
Thanks,
Tony

Hi Tony,
I would recommed you hit some of the popular .Net Development sites on the Internet. For example, just googling on .Net Enterprise Services provides links where simple samples can be reviewed. These generic code samples can then be tweaked to include ODP code for data access. If your components or code will be enlisting in transactions with MTS, hence your class or aspx page is transactional, you will need to install the Oracle Services for MTS in addtion to the ODP driver.
HTH
Jenny

Windows Server 2008R2 - Adding additional New Fibre Channel Storage will I need to reboot after mpclaim?

I am replacing an MSA 1500 Fibre Channel array with an MSA 2040 on a live system. The new array has been installed physically and connected to the switch fabric.
Both arrays are connected to a common switch fabric. The new array can see all the physical hosts on the SAN, and I have managed to setup MPIO on the least critical box but rebooted that one as I used the -r -i -a options. My question is will I be able to
run mpclaim -n -i -d "HP MSA 2040 SAN" and not have to reboot afterwards? I have read every piece of documentation and some seem to hint this is possible in 2008 R2 and later but it is not explicitly clear as MS haven't updated
all their docs to detail differences.
I suppose I am after the wisdom of experience.
Since MPIO has already been installed and working for a different array I am hoping any requirement to reboot should not be there?
Your advice greatly appreciated.
K

Hi,
If the server cannot be rebooted at the time the command is run, you could use the -n switch instead. The devices will not be claimed by MPIO until the server reboots.
For more detailed information, please refer to the articles below:
Microsoft MPIO Command Line Reference (mpclaim) and Server Core Configuration
http://blogs.msdn.com/b/san/archive/2008/07/27/microsoft-mpio-command-line-reference-mpclaim-and-server-core-configuration.aspx
Configuring Multipath I/O
http://sourcedaddy.com/windows-7/configuring-multipath-io.html
Please Note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
Best Regards,
Mandy
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Xserve, G5, Xserve RAID and fibre channel question

hi guys,
I have a Xserve conneted to Xserve RAID right now. Is it possible connect G5 to Xserve RAID thru fibre channel ? thanks

>is it possible to do ?
Not in the way you describe, no.
The XServe RAID's 14 drives are connected to two separate controllers. Drives 1-7 are connected to the upper controller. Drives 8-14 are connected to the lower one.
If your XServe is currently connected to the upper controller it's talking to drives 1-7.
If you connect the G5 to the lower controller it will be talking to drives 8-14.
Therefore you cannot use this setup to backup the data via the G5.
At the very, very least you need a fiber channel switch so that both the XServe and the G5 can connect to the same controller. However, as Tod has already mentioned, it is tricky to get multiple machines talking to the same RAID drives while avoiding corruption (there's no concept of arbitration, or ways of preventing one machine from editing a file that's in use by the other machine).
You have two basic options - one is to implement XSAN, which will handle the arbitration issue, the other is to configure the G5 to mount the RAID read-only. This should prevent the G5 from modifying a file while it's in use by the XServe (which may be sufficient for backup purposes), but you may still run into issues when the G5 tries to backup a file that's actively in use by the XServe.
In all honesty, a better solution would either to get a SCSI card that works with the XServe and do it all there, or use file sharing between the XServe and the G5 and backup over the network - it'll be slower, but a lot more reliable.

Can Xserve2,1 make Xsan disk sharing using Fibre Channel to different OS version client?

Hi, I want to upgrade 3 MacPro linked to an Xserve2,1 (MacOsX10.6.8) with fibre channel.
My question is: the operative system of the server must be the same of the clients?
Thanks!

It shouldn't matter if using same XSAN across all three. Although, it is a bit of a black art. The best place to ask these questions is http://www.xsanity.com/

The Fibre Channel Platform Registration Service could not register the platform with fabric

Hyper-V Cluster. HP StorageWorks 82E 8 Gb PCI-e Dual Port FC HBA.
Each 15 minutes, eventlog register a warning.
EventID: 2 Source:2
The Fibre Channel Platform Registration Service could not register the platform with fabric 10:00:00:05:1e:7f:74:7b.
I have teste the service. And it's started. Cluster storage validation report without failure.
Someone suggest any idea.
Thanks.

Hi,
What’s the OS version of your cluster node?
The Microsoft Fibre Channel Platform Registration Service registers the platform with all available Fibre Channel fabrics and maintains the registrations. A fabric is a network topology where devices are connected to each other
through one or more high-efficiency data paths. This service is used in support of storage area networks.
This service is installed by default on Windows Server 2008, and the service startup type is Manual.
You may try hotfix in KB 978790, and check the result.
For more information please refer to following MS articles:
The File Share Witness resource is in a failed state even though the File Share Witness directory is available, and quorum cannot be maintained in a Windows Server 2008 failover cluster
http://support.microsoft.com/kb/978790
cluster resources unresponsive
http://social.technet.microsoft.com/Forums/hu/winserverClustering/thread/886a9cb3-7723-4b64-8c15-602dadf5ced9
Hope this helps!
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Fibre Channel Data link layer

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