The IT Stuff

Power over Ethernet: 24 full PoE port and 24-port (PoE supported on 8 ports) configurations
Connectivity: Fast Ethernet and Gigabit Ethernet connectivity in 8-port, 24-port, and 48-port configurations
Integrated security, including network admission control (NAC)
Advanced quality of service (QoS) and resiliency
Single IP address, syslog, and Simple Network Management Protocol (SNMP) management for a stack of up to [...]

The Internet Protocol Suite (commonly known as TCP/IP) is the set of communications protocols used for the Internet and other similar networks. It is named from two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were the first two networking protocols defined in this standard.
The [...]

Cisco IOS (originally Internetwork Operating System) is the software used on the  Cisco Systems routers and all current Cisco network switches.
IOS is a package of routing, switching, internetworking and telecommunications functions tightly integrated with a multitasking operating system.

OSPF Packets:
OSPFv3 has five types of packets: hello, DD, LSR, LSU, and LSAck.
OSPF does not use UDP or TCP for transmitting its packets. Instead, it runs directly over IP (IP protocol 89) using an OSPF header. One field in this header identifies the type of packet being carried.
Hello—Identifies neighbors and serves as a keepalive and [...]

Denial-of-Service Attack:
In DOS Attack after gaining access to your network, the attacker can do any of the following:

Randomize the attention of your internal Information Systems staff so that they do not see the intrusion immediately, which allows the attacker to make more attacks during the diversion.
Send invalid data to applications or network services, which causes [...]