4A0-220 Exam Dumps : Nokia GMPLS-Controlled Optical Networks

The label on the top of the MPLS label stack is swapped at an intermediate node. This is because the top label is the one that is visible to the node and determines the forwarding decision. The node looks up the top label in its label forwarding table and swaps it with a new label that corresponds to the next hop or destination. The node then forwards the packet to the next node, which repeats the same process. The bottom label is only used to indicate the end of the label stack and is not swapped. References : [Nokia GMPLS-controlled Optical Networks Course | Nokia], [MPLS Label Stack - Nokia]

The GMRE notify address is an IP address used to signal failures on downstream nodes upstream to the head node. The GMRE notify address is configured on each GMRE node and is used to send a Notify message to the head node when a failure occurs on a link or node alongthe LSP. The Notify message contains the failure information and the LSP ID. The head node can then initiate a restoration process based on the Notify message. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, GMPLS - Nokia

SFD is not a GMPLS protocol, but a term used in optical networks to refer to the Source Frequency Definition, which is a parameter that specifies the frequency of a wavelength channel4. GMPLS protocols are those that enable the control and management of different types of switching technologies, such as packet, wavelength, fiber, and time-slot switching5. Some examples of GMPLS protocols are OSPF-TE, RSVP-TE, and LMP. OSPF-TE is a routing protocol that advertises the topology and the link attributes of the network6. RSVP-TE is a signaling protocol that establishes, modifies, and releases LSPs. LMP is a link management protocol that verifies the connectivity and monitors the status of the links. References:

• 4: Source Frequency Definition (SFD) - ITU
• 5: Generalized Multi-Protocol Label Switching - Wikipedia
• 6: OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS) - RFC 4203
• [7]: Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource Reservation Protocol-Traffic Engineering (RSVP-TE) Extensions - RFC 3473
• [8]: Link Management Protocol (LMP) - RFC 4204