Nokia 4A0-220 Dumps

Signaling protocols are protocols that are used by the ingress router to set up a new LSP in an MPLS network. Signaling protocols are responsible for requesting, allocating, and releasing resources along the LSP, as well as establishing and maintaining the label bindings between the nodes. Some examples of signaling protocols are RSVP-TE, LDP, and CR-LDP34. References:

• 3: Nokia GMPLS-controlled Optical Networks Course | Nokia
• 4: MPLS Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 7.1.x - Implementing MPLS Label Distribution Protocol [Cisco IOS XR Software (End-of-Sale)] - Cisco

Preemption is a mechanism that allows a higher priority LSP to tear down an existing lower priority LSP in order to obtain the required resources for its establishment. Preemption can occur when there is not enough bandwidth or other resources available on a link or node to accommodate a new LSP request. In this case, the node can select one or more lower priority LSPs that are using the resources and send them a PathErr message with a Preempt error code. This causes the lower priority LSPs to beterminated and release their resources. The node can then allocate the resources to the higher priority LSP and send a Resv message to confirm its reservation34. References:

• 3: RFC 4829: Label Switched Path (LSP) Preemption Policies for MPLS Traffic Engineering4
• 4: MPLS Applications User Guide | Juniper Networks5

 The Wait for Server Restoration (WSR) parameter in the MRN is a boolean parameter that determines whether an LI service should wait for the LO restoration or not in case of a failure.When WSR is false, the LI services do not wait for the LO restoration and restore through LI switching. This means that if an LO optical channel fails, the LI services that use that channel will switch to another available optical channel at LI layer without waiting for the LO layer to restore the failed channel. This option provides faster restoration time for LI services, but may result in suboptimal resource utilization at LO layer. When WSR is true, the LI services wait for the LO restoration and do not switch at LI layer. This means that if an LO optical channel fails, the LI services that use that channel will remain in that channel until the LO layer restores it or until a timeout occurs. This option provides optimal resource utilization at LO layer, but may result in longer restoration time for LI services. References : Nokia GMPLS-controlled Optical Networks Course | Nokia, 3. GMPLS - Nokia