Maximum number of fabric logins

[johnnywilhelm]

Hi there

I need to provide documented references for a large SAN, and have a few queries.

I have the show tech-supports for an edge-core-edge SAN consisting of 2 redundant fabrics.

There are 4 host edges, 1 core, 4 storage edges per fabric. All are MDS 9500 series directors, running SAN-OS 3.2.2a.

In the Large SAN Design Best Practices whitepaper
(http://www.cisco.com/en/US/prod/collateral/ps4159/ps6409/ps5990/white_paper_C11-515630.pdf)

there is a reference to the maximum number of fabric logins.

"The Cisco MDS Family supports up to 10,000 fabric logins in a physical fabric, regardless of the number of VSANs in the network."

1) Is this specifically refering to the number of f_ports?
2) If not, what is the 10,000 referring to?

In the Cisco MDS NX-OS Release 5.0 Configuration Limits
(http://www.cisco.com/en/US/docs/switches/datacenter/mds9000/sw/5_0/configuration/guides/limits/limits_50.html)

there is a mention of 10000 FCNS entries per fabric.

This is the only reference I can find that correlates the two limits.

The Configuration Limits for Cisco MDS SAN-OS Release 3.x
(http://www.cisco.com/en/US/products/ps5989/prod_troubleshooting_guide_chapter09186a0080679fd4.html)

makes no mention of FCNS or fabric login limits.

3) Is the reference to 10000 FCNS entries (in the NX-OS 5 limits) also the number of fabric logins?

In the show tech-support, there is a command

`show tech-support fcns`

`show fcns database vsan 1-4093`

VSAN 431:

--------------------------------------------------------------------------
FCID        TYPE  PWWN                    (VENDOR)        FC4-TYPE:FEATURE
--------------------------------------------------------------------------
0x050002    N     50:06:04:8c:52:a6:c0:69 (EMC)           scsi-fcp 253
0x050003    N     50:06:04:84:52:a6:c0:49 (EMC)           scsi-fcp:both 253
0x050004    N     50:06:04:8c:52:a6:c0:49 (EMC)           scsi-fcp 25
..
<.. output abbreviated for brevity>>
..
Total number of entries = 1066

4) Does this mean that there are 1066 fabric logins?

When I look further in to it, and see the command

`show fcns database detail vsan 1-4093`
..
------------------------
VSAN:431   FCID:0x0500b1
------------------------
port-wwn (vendor)           :10:00:00:00:c9:72:4d:9c (Emulex)   
                             [nus157_hba0_0]
node-wwn                    :20:00:00:00:c9:72:4d:9c
class                       :3
node-ip-addr                :0.0.0.0
ipa                         :ff ff ff ff ff ff ff ff
fc4-types:fc4_features      :ipfc scsi-fcp
symbolic-port-name          :
symbolic-node-name          :Emulex LPe11002-S FV2.82a4 DV2.50o
port-type                   :N
port-ip-addr                :0.0.0.0
fabric-port-wwn             :21:07:00:0d:ec:3a:44:c0
hard-addr                   :0x000000
permanent-port-wwn (vendor) :10:00:00:00:c9:72:4d:9c (Emulex) 
..

It shows that most of the entries have the port-type: N.

5) Does this mean they are N_ports, not F_ports?

I would really appreaciate answers to these questions.

[setmason · Accepted solution]

John,

Cisco NXOS Configuration Limits (reference/background link)

1) Is this specifically refering to the number of f_ports?

     Answer: Yes, the 10k logins in the Design Guide Whitepaper refer to the number of Fabric logins, not the number of physical ports.  This is because you could have a single F_Port that has multiple logins as part of it.  For example, an Nexus 5000 in NPV mode could connect to a MDS 9513 via one F_port (NP_Port on the Nexus 5k), but have many Fabric Logins (technically, one FLOGI and multiple FDISC).
2) If not, what is the 10,000 referring to?

     Answer: Number of devices logged into the Fabric not the number of ports in the fabric.

3) Is the reference to 10000 FCNS entries (in the NX-OS 5 limits) also the number of fabric logins?

     Answer: Yes, since every device out there that FLOGIs into the fabric registers with the nameserver.

4) In the below output does this mean that there are 1066 fabric logins?

In the show tech-support, there is a command

`show tech-support fcns`

`show fcns database vsan 1-4093`

VSAN 431:

--------------------------------------------------------------------------
FCID        TYPE  PWWN                    (VENDOR)        FC4-TYPE:FEATURE
--------------------------------------------------------------------------
0x050002    N     50:06:04:8c:52:a6:c0:69 (EMC)           scsi-fcp 253
0x050003    N     50:06:04:84:52:a6:c0:49 (EMC)           scsi-fcp:both 253
0x050004    N     50:06:04:8c:52:a6:c0:49 (EMC)           scsi-fcp 25
..
<.. output abbreviated for brevity>>
..
Total number of entries = 1066

Answer: Yes.

5) Does this mean they are N_ports, not F_ports?

When I look further in to it, and see the command

`show fcns database detail vsan 1-4093`
..
------------------------
VSAN:431   FCID:0x0500b1
------------------------
port-wwn (vendor)           :10:00:00:00:c9:72:4d:9c (Emulex)   
                             [nus157_hba0_0]
node-wwn                    :20:00:00:00:c9:72:4d:9c
class                       :3
node-ip-addr                :0.0.0.0
ipa                         :ff ff ff ff ff ff ff ff
fc4-types:fc4_features      :ipfc scsi-fcp
symbolic-port-name          :
symbolic-node-name          :Emulex LPe11002-S FV2.82a4 DV2.50o
port-type                   :N
port-ip-addr                :0.0.0.0
fabric-port-wwn             :21:07:00:0d:ec:3a:44:c0
hard-addr                   :0x000000
permanent-port-wwn (vendor) :10:00:00:00:c9:72:4d:9c (Emulex) 
..

It shows that most of the entries have the port-type: N.

Answer: An N_Port is an end device like a storage port or an HBA, which connects to an F_Port (Fabric Port) which is the corresponding port on the switch.  This is why you see it as an port-type of N, rather than NL (Node Loop) F, E, or FL (Fabric Loop), as only N or NL can represent the end device itself and not the port on the switch.

Hope this helps,

Seth

[johnnywilhelm]

Thanks for the comprehensive answer Seth!