Cisco VSS with ether-channel uplinks from Aggregation switches

[sushilmenon]

Hi all,

I am in the phase of designing a Cisco VSS solution with 3560 as the aggreagtion switches.

I have 2 3560 aggregation switches and 2 6509 switches. I have multiple 2960 switches connected to 3560 switches.

I want to connect 3560 switches to the vss switches. I am considering of creating 2 ether-channel uplinks of 2 gig ports in each ether-channel on ech 3560. I want to connect 1st ether-channel from 1st 3560 switch to primary 6509 and other ether-channel from same 1st 3560 switch to the secondary 6509 switch.and vice versa for 2nd 3560 switch.

Is this topology and configuration supported by Cisco VSS.

Any help on the same would be really great.

Thanks & Regards

Sushil

[Reza Sharifi · Accepted solution]

sushilmenon wrote:
Hi all,
I am in the phase of designing a Cisco VSS solution with 3560 as the aggreagtion switches.
I have 2 3560 aggregation switches and 2 6509 switches. I have multiple 2960 switches connected to 3560 switches.
I want to connect 3560 switches to the vss switches. I am considering of creating 2 ether-channel uplinks of 2 gig ports in each ether-channel on ech 3560. I want to connect 1st ether-channel from 1st 3560 switch to primary 6509 and other ether-channel from same 1st 3560 switch to the secondary 6509 switch.and vice versa for 2nd 3560 switch.
Is this topology and configuration supported by Cisco VSS.
Any help on the same would be really great.
Thanks & Regards
Sushil

Hello Sushil,

You only need one etherchannel from each 3560 to the VSS pair not 2.  So first 3560 has 2 uplinks, one to primary 6509 VSS and one to the backup 6509 VSS, then you put both links in one etherchannel and do the same for other 3560.  Remember when you creating a VSS pair the 2 6509s become logically one so there is no need for the second etherchannel.

HTH

Reza

[allan.thomas · Accepted solution]

Hi,

The important aspect to remember regarding VSS is that although they are two physical devices they act as a single logical entity, therefore if you intend on uplinking the 3560 switch to both 6509 switches then all the uplink would need to be bonded into a single port-channel and not two separate ones in order to avoid the necessity of STP. By creating two port-channels would re-introduce a loop. 

Think of the two 6509s in VSS as a single switch, so essentially it is a switch to switch connection not a triangular arrangement.

Hope this helps.

Regards

Allan.

[sushilmenon]

Thanks Reza and Allan,

Just one more query so as you all mentioned that i need a single ether-channel on the 3560 switch with one port of the ether-channel connecting to the primary vss switch and other connecting to the secondary vss switch right.

Now in this case will both my links of the ether-channel be active. In short there is no STP between the 3560 and 6513.

Now here if stp is not running my total uplink capacity is 2 Gigs. Can i use 4 uplinks from each of the 3560 and put them in a single ether-channel to doubly my uplink capacity. Is this possible.

Please let me know.

Thanks & Regards

Sushil

[allan.thomas · Accepted solution]

Hi,

Just one more query so as you all mentioned that i need a single ether-channel on the 3560 switch with one port of the ether-channel connecting to the primary vss switch and other connecting to the secondary vss switch right. YES

Now in this case will both my links of the ether-channel be active. In short there is no STP between the 3560 and 6513.  CORRECT

Now here if stp is not running my total uplink capacity is 2 Gigs. Can i use 4 uplinks from each of the 3560 and put them in a single ether-channel to doubly my uplink capacity. Is this possible.  YES, although the second 3560 4 uplinks would be in a different port-channel.

Regards

Allan.

[sushilmenon]

Hi Allan,

Thanks a lot for your prompt and accurate reply.

I have one more query about load-balacing VLAN Traffic within a single vlan. I have posted a new thread for the same in this same board.

Can you please help me out with the same as well.

Thanks & Regards

Sushil