CCNP Routing & Switching ROUTE 300-101 Chapters 1 & 2 Notes:

• TCP/IP Fundamentals
  • Routing occurs at Layer 3 of the OSI Model
  • Internet protocol (IP) is the primary protocols used to route traffic
    • Today we have the almost exhausted IPv4 and the new IPv6 addressing to chose from to route traffic.
    • At Layer 4 we have the Transport layer, which determines the way traffic is going to flow once it hits layer 3. TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are the two transport layer protocols.
    •  The IP header is where things like type of QoS, TCP/UPD, IPv4/IPv6 are determined.
    • Maximum Transmission Unit – determines the size of the packet being transmitted.
    • ICMP messages – aids in checking networking connectivity
    • Three-Way Handshake – since TCP is a reliable protocol, the 3-way handshake is one of a few items which make this possible. The 3-way handshake allows the source and destination devices to establish a session by which packets are going to be sent.
    • TCP Windowing – Allows each packet to get a sequence number which ensures that all packets are sent & recieved between the sender and receiver. 

Summary:

In summary, Internet protocol (IP) at layer 3 is used in combination with TCP/UDP at layer 4 to route traffic to the correct destination and with the needed reliability. Within each protocol the header is used to determine the parameters by which traffic will be routed. Tools such as ICMP exist to help with confirming continuity of a circuit and troubleshooting. With IPv4 being exhausted gradually networks are moving to use IPv6. Many migration options are available to aid in this transition. Lastly, as our networks grow and become more sophisticated so do our protocols. VRFs are created to help meet the ever increasing need for private, secure, and easy to setup virtual networks. 

Progress:

Pages 21-41 (3 hours)