MLAG, Does the ISC vlan forward any payload traffic

[simon_bingham]

MLAG ISC

I have a question

For a customer I have these options

Between the 2 MLag switches are these options

1. A 2 port aggregation of 1 gig links
2. A single 10 gig link ( a newer network )

So the trade off I have is bandwidth vs resilience.

So this is my question

Does the ISC vlan forward any payload traffic ? or this is purely a control channel is which case it would seem prudent to use the lower bandwidth but resilient link.

[Stephane_Grosj1]

Hi,

there'll be traffic on the ISC in the following cases (that comes to my mind):

- BUM traffic (broadcast, unknown unicast and multicast) will transit through ISC, to be dropped on the other end in steady state operation.

- single attached devices, statistically ~50% of the traffic to them will transit through the ISC

- link failure (similar to the previous case)

- L3 traffic (VRRP) if you don't have Fabric Routing on

- in some advanced designs with an IGP (OSPF) on top of MLAG, you can see steady traffic on the ISC as well

Best Regards,
Stephane

[simon_bingham]

Thankyou Stephane