[j-nsp] Qfabric

[Clarke Morledge]

Guys, I know we've probably beaten this thread to death, but I'd like to 
get back to Keegan's original question on the thread:  so what exactly is 
Qfabric?

Stefan's description that it improves on TRILL by eliminating the 
forwarding table lookup along the path is intriguing. Doug's suggestion 
that L2/L3 forwarding is integrated to avoid the hairpin turns along an 
IRB interface as in VPLS is very helpful.  Another comment is this is a 
lot like ATM with MPOA shortcuts.

All of this is great, but as I am wading through the marketing material 
and the whitepapers, I find myself trying to remember to lookup what 
"fungible" is instead of getting a good idea on how Juniper is actually 
solving the problem.

We have a good twenty plus years of work on things ranging from ATM/MPOA 
to MPLS/VPLS to now IETF's TRILL and IEEE's Shortest Path Bridging.  The 
solutions offered in these standards have their pluses and minuses, but at 
least there are (relatively) well understood published details.

Frankly, I am quite annoyed over the whole flap between IETF TRILL and 
IEEE Shortest Path Bridging.  This type of bickering in the standards' 
community doesn't help matters, and it only encourages folks like Juniper 
to take a different approach.

It seems like we are left with these proprietary solutions like QFabric, 
which comes across like "Virtual Chassis on Steroids".  But I've seen 
Virtual Chassis do some weird things, and trying to get intelligent 
information out of Juniper to try to explain them is difficult.

Perhaps there are some good white papers or documentation out there that I 
am missing.  Can anyone direct me to the really good ones?  Anything in 
George Varghese's, Radia Perlman's, an MPLS writer's, or someone else's 
generally accessible printed work that can help enlighten?  How does 
QFabric really solve the forwarding lookup delay issue and the L2/L3 
hairpin turn problem, without the yada-yada?  What about multipath? What 
about multicast replication?  What about failure recovery within the 
QFabric cloud?  I don't mean to be a stick-in-the-mud and I am interested 
to learn, but cloudy proprietary solutions just make me nervous.

Clarke Morledge
College of William and Mary
Information Technology - Network Engineering
Jones Hall (Room 18)
Williamsburg VA 23187