In VRRP (Virtual Router Redundancy Protocol), the master device maintains the virtual IP address and continues forwarding packets unless it fails. When the intermediate link for transmitting VRRP heartbeats fails, the master device does not immediately change its state because it does not receive heartbeat signals from the slave device. Consequently, the master device continues to remain the master. Additionally, the slave device will not receive heartbeat signals from the master and might assume that the master has failed, potentially taking over as the master. However, they do not both enter the Master, Slave, or Initial state simultaneously. Thus, the status of the master and slave devices remains unchanged.
IP Quality of Service (QoS) models include Best-Effort, Integrated Service (IntServ), and Differentiated Service (DiffServ). Best-Effort is the default service model for the Internet, where all packets receive the same priority. Integrated Service is a model that provides end-to-end QoS guarantees in IP networks by reserving resources for specific flows. Differentiated Service is a scalable QoS model that differentiates traffic by classifying and managing it based on predefined policies. FIFO Service is not considered a QoS model.
A VRRP virtual router can indeed have one or more IP addresses. This is a key feature of VRRP (Virtual Router Redundancy Protocol), which allows multiple virtual IP addresses to be assigned to ensure redundancy and high availability in a network. This setup allows one router to take over automatically if the primary router fails, maintaining network stability and functionality.
In BGP Graceful Restart (GR) mechanism, when a session is re-established between the BGP GR helper and its neighbor, the original forwarding entries are not deleted immediately. Instead, these entries are retained to ensure continuity of data flow and to prevent traffic loss during the restart process. The GR helper maintains these entries until it can update them based on new routing information received after the session is re-established.