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New Member

VLAN prioritization for SAN traffic

I have a stack of 3750's running two VLANs, one for NFS traffic (id 130) and one for iSCSI traffic (id 150). I have jumbo framing (MTU 9000) on VLAN 150. I'd like to try prioritizing the iSCSI traffic using 802.1p. Can anyone point me to some configuration help? Does anyone have any thoughts or experiences with this idea? Thanks!

Cisco Employee

Re: VLAN prioritization for SAN traffic

The MDS GE/iSCSI interface can set the DSCP value on outbound IP packets, but that is in the IP header (layer 3). From what I recall, the 802.1p bits are in the Layer 2 field between the MAC addresses and the Ethernet type, and from what I understand, the MDS does not provide any marking at that level.

You could mark via 802.1p inbound on the Ethernet Switch that the MDS GE port is attached to, but not directly out of the MDS GE port.

If you are interested in marking iSCSI using DSCP, here is web page describing how you set the iSCSI interface for the desired DSCP value.

Hope this helps,


Cisco Employee

Re: VLAN prioritization for SAN traffic