Latest News about Cisco Technology
June 22, 2025
Multicast Source Discovery Protocol (MSDP) In the PIM sparse mode model, the router that’s closest to the sources or receivers registers with the RP. The RP knows about all the sources and receivers for any particular group. Network administrators may want to configure several RPs and create several PIM-SM domains. In each domain, RPs have
READ MOREMulticast Control Protocols The NX-OS software supports the following protocols to implement IP multicast routing: Internet Group Management Protocol (IGMP) IGMP is used to dynamically register individual hosts in a multicast group on a particular LAN. Hosts identify group memberships by sending IGMP messages to their local multicast router. Under IGMP, routers listen to IGMP
READ MOREMulticast Forwarding In unicast routing, traffic is routed through the network along a single path from the source to the destination host. A unicast router does not consider the source address; it considers only the destination address and how to forward the traffic toward that destination. The router scans through its routing table for the
READ MOREMulticast Distribution Trees A multicast distribution tree represents the path that multicast data takes between the routers that connect sources and receivers. The multicast software builds different types of trees to support different multicast methods. Source Trees A source tree represents the shortest path that the multicast traffic takes through the network from the sources
READ MOREACI Startup Discovery The clustered Cisco Application Policy Infrastructure Controller (APIC) provides DHCP, bootstrap configuration, and image management to the fabric for automated startup and upgrades. The Cisco Nexus ACI fabric software is bundled as an ISO image, which can be installed on the Cisco APIC server through the KVM interface on the Cisco Integrated
READ MORECisco ACI Building Blocks Prior to Cisco ACI 4.1, the Cisco ACI fabric allowed only the use of a two-tier (spine-and-leaf switch) topology, in which each leaf switch is connected to every spine switch in the network with no interconnection between leaf switches or spine switches. Starting from Cisco ACI 4.1, the Cisco ACI fabric
READ MORECisco ACI Policy Model The ACI policy model enables the specification of application requirements policies. The APIC automatically renders policies in the fabric infrastructure. When a user or process initiates an administrative change to an object in the fabric, the APIC first applies that change to the policy model. This policy model change then triggers
READ MOREACI Logical Constructs The policy model manages the entire fabric, including the infrastructure, authentication, security, services, applications, and diagnostics. Logical constructs in the policy model define how the fabric meets the needs of any of the functions of the fabric. Figure 8-17 provides an overview of the ACI policy model logical constructs. Figure 8-17
READ MOREVRFs A virtual routing and forwarding (VRF), or context, is a tenant network. A tenant can have multiple VRFs. A VRF is a unique Layer 3 forwarding and application policy domain. A VRF defines a Layer 3 address domain. One or more bridge domains are associated with a VRF. All of the endpoints within the
READ MOREBridge Domains and Subnets A bridge domain (BD) represents a Layer 2 forwarding construct within the fabric. A BD must be linked to a VRF. With the exception of a Layer 2 VLAN, it must have at least one subnet associated with it. The BD defines the unique Layer 2 MAC address space and a
READ MORE