Hi Sarah,
Just to add to Jan's concise and clear answer:
1) I EEE 802.1D-1998 legacy stp standard ,no support for trunking. That means this can not support multiple vlans . correct?
Basically correct. To be more precise, 802.1D-1998 STP does not know about VLANs but it does not mean that it does not "support them". What that really means is that the 802.1D-1998 STP builds a single spanning-tree, and if VLANs are deployed over this spanning tree, they will all share the same active topology in the switched network. 802.1D-1998 STP is basically oblivious to the whole concept of VLANs but it does not preclude combining them together. Note that trunking is not a defining property of whether STP supports or does not support multiple VLANs.
2) IEEE 802.1w rstp , no trunking support hence can not support multiple vlans . Correct ?
Basically correct - see the explanation to 1) as the rationale is the same.
3) IEEE 802.1D 2004 , no trunking support hence can not support multiple vlans. Correct?
Basically correct - see the explanation to 1) as the rationale is the same. Also please note that in 802.1D-2004, STP became deprecated and omitted from the standard, and 802.1w was integrated into 802.1D-2004. So the most recent version of 802.1D actually specifies RSTP, not STP. The 802.1w does not exist anymore.
4) IEEE 802.1s supports dot1q trunk and therefore can support multiple vlans. Correct?
In fact, not quite. If you observed MST BPDUs, they are always sent untagged. 802.1s MST does not strictly depend on 802.1Q trunks. In fact, there is even no such thing as a trunk in 802.1s or 802.1Q. They define these ports differently, as ports having a single Primary VLAN ID and a set of additional VLANs. The PVID is untagged, all other VLANs are tagged. If a port has only a PVID assigned, it is what we call an access port. If it has all VLANs assigned, it is in our parlance a trunk port. But technically, MST does not rely on trunk ports in order to exist and operate. What makes MST a VLAN-aware protocol is the notion that VLAN can be mapped to MST instances, and the state of MST instance applies to all mapped VLANs. But MST really works with instances, not with VLANs, and it does not require trunking functionality in order to operate.
To put it succintly - does MST support VLANs? Absolutely. Does MST require trunks? No. Does MST require VLANs to exist in order to operate? No.
5 )IEEE.802.1s introduced MST and my book says In IEEE 802.1q -2003 ,Mst was added to 802.1Q.
All I know 802.1Q initially defined dot1q trunk. What do we mean MST was added to IEEE 802.1q-2003,? Does it mean the standards now define MST + dot1q trunking ?
Yes, absolutely. 802.1Q now includes MST and the 802.1s does not exist anymore - very similar to 802.1w that was withdrawn after it was integrated into 802.1D-2004.
Best regards,
Peter
