Protocol Functions-2

Network Time Protocol (NTP)

Used to synchronize clocks of a computer over a given network. Port 123.

Session Initiation Protocol (SIP)

Used for initiating, maintaining, and terminating real-time sessions that involve voice, video messaging, and other communication services. Port 5060 and 5061.

Lightweight Directory Access Protocol (LDAP)

Protocol for accessing and maintaining distributed directory information services over an IP network. Port 389.

Routing Information Protocol (RIP)

A distance vector protocol that uses a hop count (maximum hops of 15; 16 is infinite).

Open Shortest Path (OSPF)

Link-state protocol that uses cost. Cost is based on link speed, not hop count.

Intermediate Systems (IS-IS)

Link-state protocol that also uses cost and functions like OSPF protocol, but not as widely popular.

Enhanced Interior Gateway Routing Protocol (EIGRP)

Hybrid of distance vector and link state protocols that uses bandwidth and delay. Count Hops and Cost.

Border Gateway Protocol (BGP)

Path vector that uses the number of autonomous systems hops instead of router hops. Only exterior protocols. Doesn’t use router hops. Uses system hops. BGP makes the internet run.

First Hop Redundancy Protocol (FHRP)

Set of protocols designed to ensure network reliability by providing automatic failover to a backup router to maintain uninterrupted network service.

Hot Standby Router Protocol (HSRP)

Developed by Cisco as a redundant protocol that can establish a fault-tolerant default gateway for devices on a local network segment.

Internet Group Management Protocol (IGMP)

Used by clients and routers to let the routers know which interfaces have multicast receivers and allow clients to join a multicast group.

Protocol Independent Multicast (PIM)

Routes multicast traffic between routers and forms a multicast distribution tree

Generic Routing Encapsulation (GRE)

A tunneling protocol that encapsulates data packets within other packets It allows for the transmission of various network layer protocols over an IP network, effectively creating a virtual point-to-point link.

Gateway Load Balancing Protocol (GLBP)

Cisco-developed protocol that takes redundancy by adding load balancing capabilities into the mix.