Shteryana Shopova wrote:
On 9/4/07, Andrew Thompson <[EMAIL PROTECTED]> wrote:
On Mon, Sep 03, 2007 at 10:21:20PM +0100, Tom Judge wrote:
Andrew Thompson wrote:
On Mon, Sep 03, 2007 at 02:11:59PM +0100, Tom Judge wrote:
Hi,
I was wondering if if_bridge had been taught how to speak multiple
instance spanning tree?
Not yet. I havnt started it yet and I do not know of anyone else working
on it.
While playing with if_bridge today and a pair of Dell PowerConnect
5324's (with the recent upgrade to MSTP) I noticed that it did not seem
to be possible to enable STP on if_vlan bridge members. This would seem
to be correct as transmitting STP frames tagged with VLAN_ID would seem
to break the spec and fall into the realm of cisco PVST. However should
if_bridge be taught that the vlandev should be used for collection and
transmission spanning tree in this scenario or should if_vlan be taught
to copy untagged [R]STP frames onto the vlan interface?
Would this make it work the same as Cisco PVST? I havnt looked into how
PVST works but whatever the solution is it would need to interoperate
with other vendors. Obviously MST support is ideal. Most of the code is
already there in the form of RSTP, and MST tacks a bit more info on the
end. To be honest I have found 802.1Q-2003 a bit unclear in this area.
AFAIK, Cisco PVST is the predecessor of 802.1Q MSTP. If I remember
correctly one of the notable differences between the two is that with
Cisco PVST BPDUs are send for every spanning tree instance (also
tagged?) while with 802.1Q MSTP all information is contained in the
per instance M-records (MSTI Configuration Messages) in a single BPDU,
and BPDUs are only sent in instance 0.
cheers,
Shteryana
Yes this seems correct from what I have read, there is an instance for
every VLAN, and BPDU's are transmitted tagged on each VLAN. In MST
instance 0 is the default instance and RSTP BPDU's are transmitted
untagged on the interface, other instance data is attached to the
instance 0 BPDU's as described.
Tom
_______________________________________________
[email protected] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-net
To unsubscribe, send any mail to "[EMAIL PROTECTED]"
