SDN Overview and Evolution

Forwarding

Delivery method to the next station

Multicast Routing

Routing a datagram to multiple destinations

Least Cost Routing

Choosing the route with the lowest total cost

Routing Algorithm

Algorithm for determining the best route

Transport Layer

Responsible for message delivery between processes

Client/Server Paradigm

Communication model between client and server applications

Port Number

16-bit integer for process identification

Ephemeral Port Number

Randomly chosen port for transport layer

Well-known Port Number

Universal port numbers for servers

Socket Address

Contains IP Address and Port Number for communication

User Datagram Protocol (UDP)

Connectionless, unreliable transport protocol

Transmission Control Protocol (TCP)

Connection-oriented, reliable network protocol

Queuing

Creating queues for incoming and outgoing data

SYN Flooding

Denial of service attack due to full queue

Connection Establishment

Process of initiating a connection between hosts

Data transfer

Bidirectional transfer after connection establishment

Source Port Address

16-bit number for process on source host

Destination Port Address

16-bit number for process on destination host

Sequence Number

Number assigned to each byte in a TCP segment

Pushing Data

Sending TCP doesn't wait for window to fill, sends immediately

Urgent Data

Data requested to be read out of order by receiver

Stream Control Transmission Protocol (SCTP)

Reliable, message-oriented transport layer protocol with congestion control

RFC 4960

Official document specifying SCTP protocol standards

Multiple Streams

SCTP feature allowing multiple data streams in one connection

Multihoming

SCTP feature enabling multiple IP addresses per end for data delivery redundancy

Transmission Sequence Number (TSN)

Unit of data in SCTP, controls data transfer

Stream Identifier (SI)

Identifies each stream in SCTP

Stream Sequence Number (SSN)

Identifies data chunks in each stream in SCTP

Packets

Data and control chunks in SCTP transmitted together

Source Port Address and Destination Address

16-bit fields defining source and destination port numbers in SCTP

Verification Tag

Identifier matching packet to SCTP association

Checksum

32-bit field containing CRC-32 checksum in SCTP

Socket Programming

Enables communication between processes over a network using sockets

Electronic Mail (Email)

Process of sending messages electronically

User Agent (UA)

Client software for interacting with email services

Message Transfer Agent (MTA)

Server-side component transferring email messages between servers

Post Office Protocol (POP)

Protocol to retrieve emails to a local client, often deleting from server

Internet Mail Access Protocol (IMAP)

Protocol allowing multiple devices to access the same mailbox without deleting messages

Multipurpose Internet Mail Extensions (MIME)

Extends email message format to support non-ASCII text and attachments

Web-Based Email

Email services accessed through web clients like Outlook or Thunderbird

DNS (Domain Name System)

Resolves domain names to IP addresses for email routing

Telnet

Protocol for accessing remote computers over a network

SSH (Secure Shell)

Secure alternative to Telnet for encrypted communication

Software Defined Networking (SDN)

Approach separating network control logic from data forwarding hardware for flexibility and efficiency

Network Complexity

Modern networks include ACLs, VLANs, TE, DPI, etc., posing management challenges.

Abstractions in Programming

Higher-level languages introduce OS abstractions, simplifying programming tasks.

Data Plane

Manages packet processing and delivery based on local forwarding state.

Control Plane

Computes router state, handles routing, traffic engineering, and firewall state.

Control Plane Abstractions

Include global network view and forwarding model using OpenFlow.

SDN Applications

Utilize OSPF, Dijkstra's Algorithm, and load balancing for network optimization.

Specification Abstraction

Expresses network control program goals through a virtual network topology.

Network Virtualization

Uses virtual topology and network hypervisor to simplify network management.

SDN Abstractions

Provide control plane abstractions, emphasizing network virtualization.

Incremental SDN Deployment

Host software integrates OpenFlow switches, enabling gradual SDN adoption.

Software-Oriented Networking

Focuses on software-based control plane and edge forwarding for flexibility.

OpenFlow Basics

Defines primitives <Match, Action> for flexible packet processing.

SDN Implementations

Include OpenFlow-based forwarding models and software/hardware switches.

Routing

Process of selecting a path for network traffic

Unicast Routing

Routing a datagram to a single destination

Interdomain

Routing outside an AS or ISP

Intradomain

Routing within an AS or ISP

Distance-Vector Routing

Dynamic routing using Bellman-Ford algorithm

Link-State Routing

Routing method using link-state database and Dijkstra's Algorithm