Figure 41 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.
Figure 42 shows the case where multiple gLSPs, instantiated as black and white Ethernet ports, are bundled together in a similar manner to LAG, using a GMPLS tunnel group. That is, each member gLSP of a tunnel group effectively maps to a member port, which runs end to end between remote UNI-Cs. Note that a LAG does not and cannot terminate on the neighboring 1830 PSS UNI-N. A single IP network interface is bound to the bundle of ports represented by the gLSPs. LACP does not run across the bundle; RSVP signaling is instead used to convey the state of the gLSP and thus the corresponding member port of the tunnel group. Traffic is load shared across the tunnel group members.
