Hi Carlos,
I don't think we need to talk about *boot* targets in particular. The conversation applies equally to data LUNs. I don't think you can necessarily separate targets from zoning, either. Even if you don't configure explicit zones, the concept of the default zone (1) will apply. FC initiators, targets, zones, WWNs, are all inter-related and need to be a part of the same conversation.
So in Zen Master form (not that I'm a Zen Master, just in his form!), I'll answer your question with a question. You asked,
Why is it that WWPNs are used for [boot] targets?
And I ask,
Why do you have to use IP addresses to communicate on an Ethernet network?
The answer is, that's the way it was designed. WWNNs are not meant to be used as targets. That's not how it works.
In all seriousness, the analogy between IP network requirements and FC network requirements is only meant to point out that protocols are designed with certain implementation rules that result in a deterministic system.
For those reading and thinking that two hosts on an IP network actually send information from MAC to MAC, try not having IP addresses on your hosts and communicating. Hint: start by ripping out the IP from your TCP/IP software stack first ;-)
All the best!
Mike
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Mike Brown
VMware, Cisco Data Center, and NetApp dude
Consulting Engineer
Twitter: @VirtuallyMikeB
Blog: http://VirtuallyMikeBrown.com
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