Jeroen van der Ham wrote:
- Label proposal from Roman on the list describes the outcome of the discussion last week. Freek notes that we should only allow one label per port.
In the call I mentioned one exception: source and destination address. But I have some good hope that this is not an issue. In G.800 terms, this seems a different thing. What we're talking about is a "resource label", used in multiplexing adaptation and channels in links. "Source and destination labels" are apparently used for termination, and thus something else (for those interested: Section 6.7.1.1 of G.800, but also section 7 and 8 -- in particular Figure 18). Also, I was briefly worried that VRFs would complicate things when describing IP addresses as labels. Historically, routers routed based on destination IP address only. Most modern routers support VRFs, which -I thought- routed based on source and destination IP address. Turns out I was wrong: they route based on destination IP address and source *port*, which -I think- can be described in current NML using multiple Switching Services.
This makes it possible to described configured networks very well.
The motivation for the one-label limitation is mostly simplicity. Multiple labels might be possible, but complicates things (e.g. do we need to specify order?; can there be a stack of labels, isn't that the same as adaptations, and if so-how to related which label to which layer, etc. I rather avoid these questions for now). If this is too strict, we can extend things later. Regards, Freek