cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
1021
Views
0
Helpful
1
Replies

Problem interconnecting MDS9124 and MDS9120

snabulast
Level 1
Level 1

Hello

We are trying to connect  2 SAN switches .  Details :

cisco MDS 9124 (1 Slot) Chassis

Model number is DS-C9124-K9-SUP

Cisco Nexus Operating System (NX-OS) Software

Software

  BIOS:      version 1.0.19

  loader:    version N/A

  kickstart: version 5.0(1a)

  system:    version 5.0(1a)

cisco MDS 9100

Model number is DS-C9120-K9-SUP

Cisco Storage Area Networking Operating System (SAN-OS) Software

Software

  BIOS:      version 1.1.0

  loader:    version 1.2(2)

  kickstart: version 3.3(5)

  system:    version 3.3(5)

We want to make the  9124 an expansion of the 9120.  Therefore we want to define 2 ports in each switch to mode E, and make an ISL link.

The problem : when we try to define the E port, we get an error :

SW_A(config-if)# switchport mode E

fc1/6: (error) mode E allowed only for interface fc1/5 in group fc1/5-8

We don't want to define port fc1/5  in mode E, because , if we do that port 6,7,8 become unusable.

Any suggestions ?

Thank you.

1 Reply 1

dakester
Cisco Employee
Cisco Employee

Hi,


The 9120 has a hardware limitation.

http://www.cisco.com/en/US/docs/storage/san_switches/mds9000/sw/rel_3_x/configuration/guides/cli_3_3/intf.html#wp1242298
In the Cisco MDS 9100 Series, the left most groups of ports outlined in white (4 ports in the 9120 switch and 8 ports in the 9140 switch) are full line rate like the 16-port switching module. The other ports (16 ports in the 9120 switch and 32 ports in the 9140 switch) are host-optimized like the 32-port switching module. Each group of 4 host-optimized ports have the same rules as for the 32-port switching module.


When configuring these host-optimized ports, the following port mode guidelines apply:
You can configure only the first port in each 4-port group (for example, the first port in ports 1-4, the fifth port in ports 5-8 and so on) as an E port. If the first port in the group is configured as an E port, the other three ports in each group (ports 2-4, 6-8 and so on) are not usable and remain shutdown.


Since the 9120 (Gen1) is attaching to the 9124 (Gen2), keep this in mind.
http://www.cisco.com/en/US/docs/switches/datacenter/mds9000/sw/5_0/release/notes/nxos/mds_nxos_rel_notes_501a.html#wp419251
When a Cisco or other vendor switch port is connected to a Generation 1 module port (ISL connection), the receive buffer-to-buffer credit of the port connected to a Generation 1 module port should not exceed 255.

On the 9124, you may have to configure the interface as...
switchport fcrxbbcredit 255

Regards,
David

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: