Transport layer
The Transport layer (OSI Layer-4) does not actually transport data, despite its name. Instead, this layer is responsible for the reliable transfer of data, by ensuring that data arrives at its destination error-free and in order. The Transport layer is referred to as the Host-to-Host layer in the Department of Defense (DoD) reference model.
Dynamic Routing Protocols Part 1
IGRP (Enhanced Interior Gateway RoutingProtocol)
EIGRP is a Cisco-proprietary Hybridrouting protocol, incorporating features of both Distance-Vector andLink-State routing protocols.
Dynamic Routing Protocols Part 2
SPF (Open Shortest Path First)
OSPF is a standardizedLink-State routing protocol, designed to scale efficiently to supportlarger networks.