can dmx-4 be connected to one of 48 ports blade in MDS 9513?

A SAN port is a SAN port is a SAN port.....

A Cisco blade with 24 ports has the same IO bandwidth on the back plane as a 48 port blade, there for the oversubscription will be higher on a 48 port blade than a 24 port blade. I belive that the "sales rep" take's this into account. Read more about oversubscription here -> http://www.cisco.com/en/US/prod/collateral/modules/ps5991/prod_white_paper0900aecd8044c819_ns512_Networking_Solutions_White_Paper.html

Or if you want Brocades view of it -> http://www.brocade.com/products/competitive/oversubscription.jsp

It all comes down to capacity planing

/Lars

48ports vs 24ports - the only difference is the oversubscription rate. On the 48 port you can over-subscribe 4-1, thus leaving you with an effective 1GB.

On the 24port blade it's a 2-1 oversubscription effectively giving you 2GB.

We have 9513's, and we place our storage initiators into the 24port blades and the hosts into the 48port initiators.

To help with the oversubscription of the ports - especially for the storage array - you can set the switchport rate-mode dedicated which will not share onthe backend. However if you do this for a lot of ports inthe portchannel, then more hosts will need to use shared ports. This is OK for low I/O hosts.

Right, but the danger to that as you pointed out is the limited bandwidth available to the other ports in the port group. The DS-X9148 48-port card has 4 12-port port groups with 12Gbps of bandwidth per port group. So if you dedicate for example 4Gbps to one port for a storage array then there is 8Gbps remaining to share amongst 11 ports.

That is why it is recommended to use a line card like the DS-X9124 for backend storage ports as there are 4 6-port port groups with 12Gbps of bandwidth per port group.

But if you don't have high i/o requirements you can certainly use a 48-port card for your host and array connections. If you do this it is best to balance the storage ports across all the port groups.

Is there a good document or overview of how these port groups are set up in various switches and blades ? It's very confusing at times, since I have notes from a course saying different things than official Cisco docs.
For example:
MDS9124: 6 port groups of 4 ports ? Or is it 3 groups of 8 ports ?
MDS9134: 8 port groups of 4 plus 2 separate groups for the 10GB's ?
What about the 18+4 in a 9222i ?

I'd like an overview.... Anyone ?

I just download the white papers from Cisco on the line card modules. It not only details the features of the cards but the oversubscription rates and port group layout.

I think cisco doesn't know itself !!!

In http://www.cisco.com/en/US/prod/collateral/modules/ps5991/prod_white_paper0900aecd8044c819_ns512_Networking_Solutions_White_Paper.htmlhttp://www.cisco.com/en/US/prod/collateral/modules/ps5991/prod_white_paper0900aecd8044c819_ns512_Networking_Solutions_White_Paper.html you can clearly read that in de DS-X9124 the port groups are made up of 6 ports per group.

In http://www.cisco.com/en/US/prod/collateral/ps4159/ps6409/ps5987/ps7079/prod_presentation0900aecd80574997.pdf they mention port groups of 4 ports.

And for the MDS9134 mentioned in http://www.cisco.com/en/US/partner/prod/collateral/ps4159/ps6409/ps4358/product_data_sheet0900aecd80692efd_ps5987_Products_Data_Sheet.html it's also 4 ports per group.

So which is it ?
Is there an overview somewhere of how large port groups are on all available switches and blades ?

I just got confirmation from Cisco that the physical MDS91xx switches use port groups of 4 ports.

The blades range from:
no port groups for the 12 port blade
port groups of 6 ports per group for the 24 port blade
port groups of 12 ports per group for the 48 port blade

The B2B credits for the blades aren't bound to the blade, but set up in the MDS92/95 chassis itself. In the MDS91xx series there are 64 B2B's per port group.

I think you were confusing the 91xx series switches with the line cards. We were discussing the line cards for the 95xx directors and not the 91xx series switches. So the discussion was limited to the DS-X9124 and DS-X9148 line cards. The MDS-91xx switches as you pointed out have a different grouping than the line cards.

I know... I just thought the port groups were the same for the MDS and the line cards. Guess not.....
Of course not.... but hey: I'm only human too

Hi there,

In our efforts to clean up the forum, we came across your question / statement.

If the question / statement is still valid, not expired and you need an update please reach out again and we try to get it answered.

As for now we will set it to “answered.”

Regards,

Jim