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Glossary

Michael Miele edited this page Jan 6, 2022 · 49 revisions

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


A

ACL

Access Control List

Appliance

Server with SmartNics installed (for CPS performance increase) to accept traffic redirected from the destination host.

ARP

Address Resolution Protocol

ASN

Autonomous System Number

AZ

Availability Zones are unique physical locations within an Azure region, designed to provide a software and networking solution to protect against datacenter failures, and to provide increased high availability (HA) to our customers. See Build solutions for high availability using availability zones.

B

BGP

Border Gateway Protocol

Baremetal

Entire node not running any custom SDN software (connected to SDN/VNET via intelligent router/appliance)

Bump in the wire

Bump = processing engine 2 bidirectional ethernet interfaces (1 for each side of processing engine) Each direction provides 1/2 the capacity of the NIC. Ex: 400G provides 200G bump-in-the-wire

C

Cluster

Collection of Nodes across different Racks

Connection

Control plane communication between sender and receiver (usually involves handshake)

Customer Address

Address visible inside Customer VM

D

DC

Data Center

DHCP

Dynamic Host Configuration Protocol (IPv4)

DHCPv6

Dynamic Host Configuration Protocol (IPv6)

DSR

Direct Server Return

DSR VIP

Virtual IP used for Direct Server Return

E

ELB

External Load Balancer

ENI

Elastic Network Interface. Eni, Vnic, VPort are used interchangeably. They all in the general sense mean a VM's NIC.

F

Flow

Single transposition - Data plane stream of packets between sender and receiver that shares key IP header information. TCP conversation entered into device flow table as defined by Tuple (SrcIP, DestIP, Src Port, Dst Port, Protocol) between source and destination. May also have modified Tuple attributes in future.

Flow Table

Flow table is view into memory space of a device capturing established TCP connections, tuple information, and current TCP state.

G

gRPC

Google RPC

GW

Gateway

H

HA

High Availability

I

IPSec

IPSec tunnel or IPSec device

ILB

Internal Load Balancer

IPv4

IP protocol Version 4 (ex. 10.1.2.3)

IPv6

IP protocol Version 6 (ex. 2001:1234:abcd::1)

J

JSON

JavaScript Script Object Notation

K

L

LB

Load Balancer

LPM

Longest-Prefix-Match algorithm commonly used in routing

M

MAC

MAC Address (Media Access Control)

Mapping

Mapping transformation between CA:PA:MAC

N

NA

Neighbor Advertisement

NDP

NMAgent

Used to translate APIs to SAI

Node/Blade

Single Physical Machine in a Rack

NS

Neighbor Solicitation

NVA

Network Virtual Appliance (VM that might have forwarding or filtering functionality – ex. router or firewall deployed as Linux/Windows VM/baremetal appliance).

NVGRE/GRE

Generic Routing Encapsulation (Protocol)

O

Overlay

The overlay folder is designated for the DASH APIs. Please note, the overlay router is not the same as the SONiC router. The DASH overlay API will be exposed for flexibility (and to refrain from introducing customer attributes into the SAI community). There will be no overlap between SAI/DASH APIs and DASH APIs. For now, we consider the DASH API to be 'NB', SAI is 'SB'.

P

PA

Provider Address (internal Azure Datacenter address used for routing)

Peering

Network relationship between two entities (usually between two VNETs – ex. VNET Peering

Prefix

For IPv4: (0-32) – example 10.0.0.0/8 For IPv6: (0-128) – example: 2001:1234:abcd::/48

Q

R

RA

Router Advertisement

Rack

Standard size DC rack – a physical unit of containment for DC equipment, dependent upon Rack SKU. Contains varying equipment including such as blades, switches (T0, MGMT, Console), PDUs, Rack Managers, etc…

Region

A set of datacenters deployed within a latency-defined perimeter and connected through a dedicated regional low-latency network. See Regions and Availability Zones.

RS

Router Solicitation

S

SDN

Software Defined Networking (high level name for the Virtual Network and its elements)

SONIC

Software for Open Networking in the Cloud. See SONiC.

Spoof Guard

Rule put in place to prevent VM from spoofing traffic

SAI

The Switch Abstraction Interface (SAI) is a hardware abstraction model for switching silicon (ASICs). It is an open-source framework that allows ASICs to be represented in software. This means you can use a Broadcom ASIC the same way as one from Mellanox or Cavium XPliant. This framework let developers target switching platforms in an agnostic way; as long as you have the necessary ASIC driver, you’re good to go. SAI locates the abstraction in the user space, while other frameworks, such as switchdev, locate the abstraction in the kernel space. Microsoft open-sourced SAI in 2015.

SDN

The Software-defined networking (SDN) technology is an approach to network management that enables dynamic, programmatically efficient network configuration in order to improve network performance and monitoring, making it more like cloud computing than traditional network management. SDN is meant to address the fact that the static architecture of traditional networks is decentralized and complex while current networks require more flexibility and easy troubleshooting. SDN attempts to centralize network intelligence in one network component by disassociating the forwarding process of network packets (data plane) from the routing process (control plane).

The control plane consists of one or more controllers, which are considered the brain of the SDN network where the whole intelligence is incorporated. However, the intelligent centralization has its own drawbacks when it comes to security, scalability and elasticity and this is the main issue of SDN.

SDN was commonly associated with the OpenFlow protocol (for remote communication with network plane elements for the purpose of determining the path of network packets across network switches) since the latter's emergence in 2011. However, since 2012 OpenFlow for many companies is no longer an exclusive solution, they added proprietary techniques. These include Cisco Systems' Open Network Environment and Nicira's network virtualization platform. For more information, see Software-defined networking.

Smart ToR

what does this mean in relation to DASH?

T

TCP

Transmission Control Protocol

ToR

Top of the Rack Switch (aka ToR or T0)

U

Underlay

Also known as 'dataplane' actions. Routing and tunneling, managed by BGP. Controlled by SONiC via SAI.

V

VFP

Virtual Filtering Platform

VIP

Virtual IP (IP exposed on Load Balancer)

VM

Virtual Machine

VNET

Virtual Network

VNI

VNI (Vnet Identifier) = VXLANID or GRE key

VPort

Eni, Vnic, VPort are being used interchangeably. They all in the general sense mean a VM's NIC.

VXLAN

Virtual Extensive Local Area Network (Protocol)

W

X

XML

Extensible Markup Language (Format)

Y

Z

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