The show isis neighbors command is used to display the Intermediate System to Intermediate System (IS-IS) neighbors that the router has discovered. This command is essential for troubleshooting and verifying the IS-IS network's topology and ensuring that the router has formed the correct adjacencies with its neighbors.

Remember that SSM is an extension of IP multicast where datagram traffic is forwarded only from explicitly joined multicast sources to receivers. It creates source-specific multicast distribution trees without shared trees.
Reference:
Cisco PIM-SSM Configuration Example
Cisco IP Multicast: PIM Configuration Guide

In OSPF, the election of the designated router (DR) and backup designated router (BDR) is based on the OSPF network type. The network types include:
Broadcast: This is the default network type for Ethernet interfaces. In a broadcast network, OSPF elects a DR and BDR. All other routers become DROTHERs. To prevent the election of a DR/BDR, you can configure the interface as non-broadcast (NBMA) using the ip ospf network non-broadcast command.
Point-to-Point: This network type is used for point-to-point links (e.g., serial links). There is no DR/BDR election in point-to-point networks.
Point-to-Multipoint: This network type is used for point-to-multipoint links (e.g., Frame Relay). There is no DR/BDR election in point-to-multipoint networks.
Point-to-Multipoint Non-Broadcast: Similar to point-to-multipoint, but explicitly configured as non-broadcast. There is no DR/BDR election in point-to-multipoint non-broadcast networks.
Loopback: Loopback interfaces are always treated as point-to-point.
Virtual-Link: Used for OSPF virtual links.
Sham-Link: Used for OSPF sham links.
Demand Circuit: Used for demand circuits (e.g., ISDN).
Non-Broadcast: Explicitly configured as non-broadcast. There is no DR/BDR election in non-broadcast networks.
Reference:
Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) v1.0 Cisco Learning Network Store - SPCOR Training

Cisco IOS XE Software is an open and flexible operating system optimized for a variety of network infrastructures. One of its key enhancements over Cisco IOS Software is the support for symmetric multiprocessing (SMP). This allows the operating system to efficiently utilize multiple CPU cores, improving performance and scalability for network services.