Figure 1 illustrates the first model. Multiple gLSPs are established between a pair of remote UNI-C nodes. Each gLSP is bound to a separate IP network interface at the UNI-C. RSVP signaling across the UNI is used to ensure that the gLSPs are SRLG diverse (by explicitly signaling the SRLG list to avoid in an XRO for every gLSP, or automatically collecting the SRLG list for a gLSP which does not have an XRO, and then signaling a subsequent gLSP including this collected list in its XRO). Protection is provided at the IP layer by hashing across the IP network interfaces associated with each gLSP. The operational state of each IP interface can be tied to the operational state of its gLSP (controlled using RSVP) or using mechanisms in the IP overlay such as BFD.
