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C3000 + BL460c + Cisco 3020 switch, mapping downlink to uplink ports on 3020 for Mezz1 NIC

ktklein
Occasional Visitor

C3000 + BL460c + Cisco 3020 switch, mapping downlink to uplink ports on 3020 for Mezz1 NIC

Ok, here is the scenario - a single C3000 enclosure w/4 BL460c blades (eventuially it will be 8 BL460c blades).  Each blade contains the QLogic iSCSI Dual-Port adapter in Mezz1 and the a Quad-Port NIC in Mezz2.  Furthermore, all four ICs have a Cisco 3020 installed.  I am fully aware the dual Gig/E NICs onboard the BL460c route to ICB1, that the QLogic dual port iSCSI NIC routes to ICB2 and that the QuadPort NIC in Mezz2 routes to both ICB3&4.  Outside of the C3000 there are a pair of ProCurve 2910al switched being utilized specifically for MPIO iSCSI traffic which ties back to a single Dell/EqualLogic PS6000XV SAN w/dual controllers (active/passive) each having 4 Gig/E ports.  Since both iSCSI ports on Mezz1 route to ICB2, in order to provide HA and MPIO, I need to know if it is possible and how to route to both external switches from any given blade through the single 3020 Cisco switch installed in ICB2.  There are 8 external uplink ports but I cannot find anywhere where it is stated how the downlink ports map to the uplink ports and if it is configurable.  I know my single point of failure is the 3020 itself, but the goal barring that as a failed component is to have four of the 8 uplink ports go to one 2910al and the other four uplink ports go to the second 2910al.  From there each 2910al ties in to the dual controllers on the SAN.  I would like iSCSI NIC-1 on any BL460c in Mezz1 to be routed to the first 2910al and iSCSI NIC-2 on any BL460c in Mezz1 to be routed to the second 2910al.  This way if a SAN controller or 2910al switch fails, I still have an active/open iSCSI path from c3000 and all BL460 blades to the SAN.  Can someone please point me to any supporting documentation that would allow this to happen?  Thanks in advance for your help!

1 REPLY
Casper42
Trusted Contributor

Re: C3000 + BL460c + Cisco 3020 switch, mapping downlink to uplink ports on 3020 for Mezz1 NIC

This is inherantly a networking question.

I think the obvious answer is to connect the 2 2910al's to each other and then use Spanning Tree amongst the 3 switches to decide which path to take.

When a single 2910al fails, Spanning Tree will re-route the traffic through the other one.
I dont know EqualLogic but the failure there depends on if they are using a single IP and NIC Teaming of some sort or if they are using 2 IPs and iSCSI MPIO to route traffic. Either way, if your servers are configured right for the iSCSI connections the failure of a controller should re-route traffic to the other controller automatically.

Short version again is to just let Spanning Tree do its job.


Now, with all that said, if you really wanted to trick the ssytem, you could configure the 3020 with 2 different VLANs and route half of every blade server to one and half to the other, and then do the same for the uplinks. On the uplink side you would somehow need to put it into access mode and NOT persist the VLAN tags through to the 2910 while maintaining the multi port channel/trunk.
This would game the system a little and force the 3020 to route things a certain way. I dont know enough about IOS to give you any examples of the code to make it work though.