[rbridge] rbridge Digest, Vol 50, Issue 2

[Francois Tallet (ftallet)]

Hi Steve,

| > 2.5 page 8
| > MST arguably provide a max of 65 instances: one CIST and up to 64
| MSTIs. I don't
| > understand "one per group of vlans" -> a given vlan is mapped to a
| unique instance.
| 
| A group of Vlans can be mapped to an IST.  It isn't 
| necessarily a 1:1 mapping of vlans to instances, in fact, it 
| usually isn't...  It reads clearly to me, can you describe 
| how you are reading it, or what the problem is?
| 

There are 4K vlans and each of them must be mapped to a unique instance
among 65, so of course, more than one vlan can be mapped to a particular
instance. But a given vlan cannot be mapped to two different instances,
that's why the "one instance per group of vlans" did not seem very clear
to me. That's not arbitrary groups of vlans.

| > 
| > 3.1 page 9-10:
| > I think that using STP, you are guaranteed that there is no
| duplication and out of order
| > frames. Frames in transit could be duplicated or re-ordered while
| RSTP/MST converges. I
| > think that if TRILL relies on TTL to mitigate loops, we'll certainly
| get more duplication of
| > frames, and more often.
| > 
| 
| Can you describe the reasoning here?  Do you mean during 
| non-convergence times?
| 

Well, that might just be my ignorance of the detail of TRILL;-) 802.1Q
acknowledges that some applications are sensitive to duplication and out
of order frames and might require STP in the network. If TRILL provides
equivalent capability in this regard, is there a way that we can ensure
that we won't get out of order and duplicate frames, even during
reconvergence?

Regards,
	Francois

| Steve
| 
| 
| 
| 
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| End of rbridge Digest, Vol 50, Issue 2
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