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IVR NAT - can someone explain how this works?

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IVR NAT - can someone explain how this works?

Postby Guest » Thu Jul 29, 2010 7:20 pm


The CLI config guide, cookbook, and other things I have found do not explain exactly what is getting translated to what with regards to IVR NAT.  I setup a simple scenario, and its all working but I am trying to understand how virtual domains and NAT in general is making it all work.

I setup two switches, MDS1 and MDS2.  I put VSAN 10 on MDS1 with a single HOST and VSAN 20 on MDS2 with a single DISK.  I made a common transit VSAN between them, VSAN 99 via FCIP.  Here is my confused take on what is happening.

HOST can only communicate with DISK if it were in its own VSAN10, which its not.  So a FCID is created in VSAN10 of 0x9a6e9f so it can talk to it.  This is using domain 9a, which is a virtual domain, not an actual domain so when traffic is directed to it, the MDS re-writes it to 0x736ef8 which is a virtual domain fcid, then the far side mds notices it can get to that pwwn and maps it back to the real fcid in vsan 20 of 0x0900ef.  Is this even close?  I just want to understand how the "routing" is really working.  I understand there is a topology table built, which in this case it is:

MDS1        10,99

MDS2        20,99

(I am using auto topology).  Below I have outputs I captured.  I had to type these in by hand as there was no way to cut/paste of of the lab I was using.  I appreciate any help on this, sorry for the marathon of posts here lately.

MDS1

HOST     VSAN10

MDS2

DISK       VSAN20

I setup an IVRZoneset so that the HOST and the DISK could see eachother.  I am using CFS and IVR NAT as well.

So it works great, the HOST can see the DISK.  But I am trying to find out about the translations, here are the tables:

P26-MDS-1# show fcns database

VSAN 10:

---------------------------------------------------------------

FCID          TYPE     PWWN                    (VENDOR)     FC4-TYPE:FEATURE

---------------------------------------------------------------

0x9a6e9f     N     22:6e:00:0c:50:17:26:00     (Seagate)     scsi-fcp:target

0xbd0000     N     21:00:00:e0:8b:07:4c:5a     (Qlogic)     scsi-fcp:init

Total number of entries = 2

VSAN 99:

---------------------------------------------------------------

FCID          TYPE     PWWN                    (VENDOR)     FC4-TYPE:FEATURE

---------------------------------------------------------------

0x736ef8     N     22:6e:00:0c:50:17:26:00     (Seagate)     scsi-fcp:target

0xa85c9f     N     21:00:00:e0:8b:07:4c:5a     (Qlogic)     scsi-fcp:init

Total number of entries = 2

P26-MDS-1# show flogi data

------------------------------------------------------------------

INTERFACE     VSAN     FCID               PORT NAME               NODE NAME

------------------------------------------------------------------

fc1/5          10     0xbd0000     21:00:00:e0:8b:07:4c:5a     20:00:00:e0:8b:07:4c:5a

Total number of flogi = 1.

P26-MDS-2# show fcns database

VSAN 20:

---------------------------------------------------------------

FCID          TYPE     PWWN                    (VENDOR)     FC4-TYPE:FEATURE

---------------------------------------------------------------

0x0900ef     N     22:6e:00:0c:50:17:26:00     (Seagate)     scsi-fcp:target

0x385c50     N     21:00:00:e0:8b:07:4c:5a     (Qlogic)     scsi-fcp:init

VSAN 99:

---------------------------------------------------------------

FCID          TYPE     PWWN                    (VENDOR)     FC4-TYPE:FEATURE

---------------------------------------------------------------

0x736ef8     N     22:6e:00:0c:50:17:26:00     (Seagate)     scsi-fcp:target

0xa85c9f     N     21:00:00:e0:8b:07:4c:5a     (Qlogic)     scsi-fcp:init

P26-MDS-2# show flogi data

---------------------------------------------------------------

INTERFACE     VSAN     FCID               PORT NAME               NODE NAME

---------------------------------------------------------------

fc1/6          20     0x0900ef     22:6e:00:0c:50:17:26:00     22:6e:00:0c:50:17:26:00

Total number of flogi = 1.

P25-MDS-1# sh ivr virtual-domain

-----------------------------------

VSAN   # Domains    IVR Virtual Domains

-----------------------------------

10         1                        154

99         2                        115,168

Guest
 

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Re:IVR NAT - can someone explain how this works?

Postby Guest » Thu Jul 29, 2010 8:49 pm


I found the command "show ivr internal fcid-rewrite-list" and think I can follow it for the most part.  I will keep searching for some docs on this, but I can see where its showing source/destination id's, and can be traced thru...........this is the "nat translation" table I was looking for.

Guest
 

Re:IVR NAT - can someone explain how this works?

Postby Guest » Thu Jul 29, 2010 10:28 pm


You found the correct command to view how the FCID is rewritten as the frame is transferred from 1 VSAN to another.  The re-writes for data frame headers are done by the line cards at wire rate.  Some control frames that contain the FCID in the payload are routed to the supervisor so that the payload can be updated with the new FCIDs as well.

- Mike

Guest
 



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