Network Performance and - Measuretronix...(802.3at Type 1) 802.3at Type 2 Power available at powered...


Network Performance and Troubleshooting Seminar

29 Aug 2017

Bai Qing (a.k.a BQ)Technical Consultant, CCIE#[email protected]

mailto:[email protected]


Agenda

• Network Performance in Modem Network• Validation Methodology• Field Validation Challenges

– Existing tools• Wireless Performance• Solution Demonstration• Q&A

COPYRIGHT © 2016 NETSCOUT, SYSTEMS, INC. ° CONFIDENTIAL & PROPRIETARY 4

What is the Network Performance?

• Network Performance and Troubleshooting

LB Web App DB

WAN

Local WAN DC


Challenges-Plan, Deploy and Validate• Little or no on-site pre-qualification is done but the status of pre-existing

network can affect network design and schedule of project

• The belief that network will work once deployed

• No historical data to compare to

• Real-time validation/verification is cumbersome

• Deployment team has no tool and/or training to validate network connectivity


Challenges - Troubleshooting

• Network support staffs are overloaded and under-skilled

• Difficult to troubleshoot switch network and remote sites

• Troubleshooting takes too long

Does this look familiar??

End User


What Should We Do?

• Performance Validation

• Troubleshooting

• Performance Validation


Service Validation

• Access layer services– POE– DHCP– DNS– Connectivity

Typical device types by PoE type

• IEEE 802.3af

• IEEE 802.3at PoE+

Presenter

Presentation Notes

Most non Pan Tilt Zoom (PTZ) cameras are 802.3af devices (i.e. lower power) PoE + is typically needed when working with motorized devices such at PTZ cameras (i.e. higher power)


POE Equipments Validation


POE Testing Result

Basics of PoE functionality

• Power Source Equipment (PSE)– Switch

• Powered Device (PD)– VoIP phone

• Two ways to power a device– End Span– Mid Span

End-Span Mid-Span

Presenter

Presentation Notes

There are two flavour of the power sourcing equipment connectivity. The power sourcing equipment (PSE) typically a switch commonly called the end-span or endpoint and provides the power on the Ethernet cable. Alternatively an external power over Ethernet injector referred to as a mid-span or mid-span device can be used if the switch does not provide PoE. Endspans are normally used on new installation or when the switch has to be replaced for other reasons, which makes it convenient to add the PoE capability. Midspans are used when there is no desire to replace and configure a new Ethernet switch, and only PoE needs to be added to the network. When using a mid-span injector the distance limitation still applies from the point of the injector to the PD. When you can, use and End-Span as it reduces complexity and yet another device that needs to be plugged into power.

PoE Specifications

Property 802.3af (802.3at Type 1)

802.3at Type 2

Power available at powered device (PD)

12.95 W 25.50 W

Maximum power delivered by power sourcing equipment (PSE) 15.40 W 30.0 W

Voltage range (at PSE) 44.0–57.0 V 50.0–57.0 VVoltage range (at PD) 37.0–57.0 V 42.5–57.0 V

IEEE Standard PoE Parameters and comparison

Presenter

Presentation Notes

Before we look into the detail POE specification, there are two key terminologies you have to remember. PSE stands for Power Sourcing Equipment which will provide the power. PD stands for Powered Device which is the end points that will get the power. The original IEEE 802.3 af standard written in 2003 provides up to 15.4 W of DC power to each device. However, only 12.95 W is assured to be available at the PD as some power dissipates in the cable. The updated IEEE 802.3AT standard written in 2009 is also known as PoE Plus and provides up to 25.5 W of power. Important to note that this standard prohibits a powered device from using all four pairs for power even in the case of 1000 Base-T Both of these amendments have since been incorporated into the IEEE 802.3 publication written in 2012. The IEEE standard for PoE requires Cat 5 cable or higher for higher power levels, but can operate with Cat 3 cable if less power is required.

Basics of PoE functionality

• Power Source Equipment (PSE)– Switch

• Powered Device (PD)– VoIP phone

• Two ways to power a device– End Span– Mid Span

End-Span Mid-Span

Presenter

Presentation Notes

There are two flavour of the power sourcing equipment connectivity. The power sourcing equipment (PSE) typically a switch commonly called the end-span or endpoint and provides the power on the Ethernet cable. Alternatively an external power over Ethernet injector referred to as a mid-span or mid-span device can be used if the switch does not provide PoE. Endspans are normally used on new installation or when the switch has to be replaced for other reasons, which makes it convenient to add the PoE capability. Midspans are used when there is no desire to replace and configure a new Ethernet switch, and only PoE needs to be added to the network. When using a mid-span injector the distance limitation still applies from the point of the injector to the PD. When you can, use and End-Span as it reduces complexity and yet another device that needs to be plugged into power.

Points of Failure


Points of failure• Most Common

– Cable faults– Switch provisioning of PoE

• Didn’t turn PoE on port• Power limited per port

– Switch over subscribed from a PoE perspective– Incompatibility between PD and PSE

• Any of these can cause a problem– Non standard compliance – Non compatibility– Legacy devices– Equipment failure

Presenter

Presentation Notes

Sometimes, the POE might be fail to operate. For example, cable faults will cause the POE not working. Engineer in the field might forget to turn on POE port or power limited by the port. Like recently I bought a Cisco 3560 POE switch, it only can provide up to 15.4 W per port. If the switch is over subscribed, then the power device might not work as well. Incompatibility between PD and PSE might also cause the issue. Of course, there are some other common failure such as... Non standard... .... Equipment failure...

DHCP• DHCP (Dynamic Host Configuration Protocol)

– first defined in RFC 1531 1993• Automatically assign IP addresses and configuration information (a scope) to a client.• Uses the DORA process to automatically acquire an address from the local DHCP

server.– Discover– Offer– Request– Acknowledge

• May also provide other services like DNS.

Presenter

Presentation Notes

Dynamic Host Configuration Protocol (DHCP) is a network protocol used to automatically assign IP addresses. Network Adapters can be set statically (manually) but this is usually reserved for setting IP addresses and subnets for devices in the networks such as Switches, Routers and servers which are permanently connected to the network. So using DHCP to connect client to a network automatically is more convenient. During the DHCP process a scope i.e. configuration information is also provided including a lease time of the address to devices such as servers, desktops and mobile devices like laptops tablets and phones. The DHCP address and configuration information will allow these devices to communicate on a network using the Internet Protocol (IP). DHCP clients use the DORA process (see below) to automatically acquire an IP address from the local DHCP Server. If more details required Discover: When a client has completed auto negotiation and is linked to the Ethernet network it broadcasts a discover message to find the DHCP Server. The discover message may have options included that suggest values for the IP address and lease time. If the DHCP server is not discovered on the local subnet, BOOTP relay agents can forward the discover message to other DHCP servers. Offer: When the DHCP server receives the broadcast packet, it sends back an Offer packet with a reserved address and other configuration parameters in DHCP options. The DHCP server may not reserve the address but send an ICMP Echo Request packet to the offered IP address to check if it’s already in use. Delivery of the DHCP offer may require the use of the BOOTP relay agent to return the Offer to the client. Request: The DHCP client may receive one or more offers from different DHCP servers. The client chooses only one offer based on the configuration parameters offered. A DHCP request is then broadcast by the DHCP client including the 'server identifier' option to indicate which server has been selected, options specifying the desired configuration values and the 'requested IP address' option to the value in the Offer message from the server. If the client receives no Offer the client times out and retransmits the Discover message. Acknowledge: When the DHCP server receives the request message, if it’s not the server selected it uses the request message as notification that its offer has been declined. The selected server commits the binding for the client to persistent storage and responds with an Ack message containing the configuration parameters for the requesting client. If the selected server cannot satisfy the DHCP Request message i.e. the address has already been allocated to another client then the server will respond with a DHCP NACK message.

https://tools.ietf.org/html/rfc1531

Common DHCP Problems

• DHCP server not found.• Wrong IP address provided from server as switch incorrectly

provisioned• Connection into the wrong VLAN (Virtual Local Area Network)

which is isolated from the DHCP server• DHCP server provides duplicate address• Running out of IP address in the IP address DHCP Pool• Network slow connection affecting DHCP operation• Multiple DHCP servers, provides wrong scope, i.e. home router• DHCP relay configured wrongly

Presenter

Presentation Notes

If the selected server cannot satisfy the DHCP Request message i.e. the address has already been allocated to another client then the server will respond with a DHCP NAck message. When the client receives the DHCP Ack message with configuration parameters, the client performs an ARP to the allocated network address and notes the duration of the lease. At this point, the client is configured. If the client gets a response from the ARP probe, the client sends a DHCP Decline message to the server and restarts the configuration process after waiting a minimum of 10 seconds. When the client chooses to relinquish its DHCP address it sends a DHCP Release message to the server with its network address. Since most clients do not know when users will unplug them from the network, DHCP does not make the DHCP release mandatory. This process is usually reliable and dependable, but it can go wrong. These are some of the problems that may happen during the DHCP process. Wrong address where a static IP address has been set and the DHCP setting to obtain an IP address automatically need to be re-established for the adapter card. Alternatively a problem in the DHCP process may leave the adapter with a default address. DHCP server cannot be found when the discovery packet is sent. This could be a problem with how the device is connected into the network i.e. it could be connected into the wrong VLAN (Virtual Local Area Network) i.e. a voice for a network. It could be also be a problem with the DHCP not being online, too busy or on a congested link that is dropping packets.


Common DHCP Problems Illustration

Data IP Range

Voice IP Range

I am DHCP server

Phone requires Option 150 to point to TFTP Server

Common DNS problems

• Slow network connection affecting DNS operation

• Slow Internet connection• Name not resolved, due to connectivity problems • DNS resolver server delivering wrong address from cache• DNS problems caused by network performance or connectivity

issues need to be solved in two parts– What were the DNS issues, identify what part of the network is bad.– Fix the network performance or connectivity issue

How Does DNS work ?

• The Internet is based on IP addresses, not domain names

• Meaning every Web server requires a DNS server to translate names to IP addresses

• To connect to a server using a domain name requires the DNS process..

• TLD = Top level domain i.e. .com. Org etc.

Resolver or Local Server

Presenter

Presentation Notes

Because the Internet is based on IP addresses, not domain names, every Web server requires a DNS server to translate domain names into IP addresses. When the client device wants to connect to specific server or service using a Domain name or URL it follows this process. The client asks the Resolver name server, which may be local to your network or at your ISP (internet service provider) to resolve the domain name to an IP address. The Resolver name server looks in its cache to see if it has the IP address for the Domain name. If it does, it returns it to the client. If the Resolver name server does not have the address then it refers the request on by asking the Root zone name server the address of the Domain name. The Root name zone server searches its zone file for the Domain name. If it does not find an associated address it provides the IP address of the TLD (top level domains) zone name server, for the domain name i.e. .com requested. The Root zone name server returns this IP address to the Resolver name sever. On receiving the IP address of the IP address of the TLD zone name server, the Resolver server send the domain name request to the .com or TLD domain zone name server. The .com or TLD domain zone name server searches its zone file for the Domain name and if it is unable to find the Domain name it is able to provide the IP address of that domain name server. Which it send s back to the Resolver server. The Resolver server send the Domain name request to the Domain name zone server The Domain name zone server searches for the domain name and provides the IP address back to the Resolver server. The resolver server responds with the IP address back to the requesting client. Who in turn uses the IP address to request the information or page information from the Domain name Server. This takes seconds or fractions of a second. If the Domain name is initially resolved by the local Resolver server it could only take mille seconds (mS).


DNS Issues Illustration

SingTel DNS Server: 165.21.83.88

Corporate DNS Server: 192.168.20.20


Field Technician Work Flow

Turn on WiFi

Search the SSID and connect

Web browser to 172.16.9.9

Optional to verify if 1Gb test is needed

Connect to the network to test

Technician can add comment

here


Link-Live View of ResultTest results sent to

sub-folder automatically via sticky comment

Per test comments field


Email View of Result

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Testing ReportCustomized Logo

Folder Specific Results

PDF or CSV Report format

Additional Detail on Job


How to Validate the Performance?

• Network Performance and Troubleshooting

LB Web App DB

WAN

Local WAN DC


Testing Methodology

• RFC2544

Use Cases for Y.1564 and RFC 2544• RFC 2544 testing good for validating

throughput on your links.

• Y.1564 validation allows for very high flexibility in simulating testing scenarios to be very close to the real active network traffic.

• Y.1564 is leveraged for SLA validation (such are Bandwidth CIR/EIR/DISCARDED traffic, Frame Loss, Frame Delay, Frame Delay variation , QoS and VLAN marking to name a few).

Presenter

Presentation Notes

What makes ITU-T Y.1564 standard unique is that it allows for complete validation of Ethernet SLA in one test. ITU-T Y.1564’s focus is threefold: - First, the methodology serves as a validation tool, ensuring that the network complies with the SLA by ensuring that a service meets its key performance indicators (KPI) at different rates, within the committed range. - Second, the methodology ensures that all services carried by the network meet their KPI objectives at their maximum committed rate, validating that under maximum load the network devices and paths are able to service all the traffic as designed. - Third, service testing can be performed for a medium to long test period, confirming that network elements can properly carry all services while under a significant load extended over a significant period of time (sometime referred to as a soaking test) IETF RFC 2544 was created to evaluate the performance characteristics of network devices in a lab. But since it includes throughput, burst, frame loss and latency with the lack of other standards it became commonly used in real networks and is being used in Ethernet-networks globally. It does not however include all required measurements such as packet jitter, QoS measurement and multiple concurrent service levels.

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Network Performance Test Methodologies • OneTouch-to-OneTouch test based on

RFC2544 method

• OptiView-to-OneTouch 10G test based on ITU Y.1564 method

• What is ITU Y.1564?– Standard which defines network performance

test procedures for carriers

• Why did we implement ITU Y.1564?– Superior results as compared to RFC 2544

legacy standard – Leverages extensive work done by industry

experts, lends credibility to NPT – Consistency with a worldwide industry

standard; enables assess to carriers

• How does ITU Y.1564 compare to other methodologies?

35

Network Performance Test

1. Isolate network performance issues faster.2. Validate the performance of your 1 & 10G infrastructure.3. Validate service provider SLAs.4. Assess the network for deployment of video and VoIP

OneTouch AT OneTouch AT 10G• Wired performance testing ≤ 1 Gbps• Wi-Fi performance testing ≤

600Mbps• To reflector or peer (or self if Wi-Fi)

• Wired performance testing ≤ 10 Gbps*

• To reflector, peer or OptiView XG tablet

XG req’d for 10G test

Presenter

Presentation Notes

Answers question: How is my network performing? Is QoS being maintained (by carriers as well as own network) end-to-end; important for real-time, critical apps apps voice, video to perform as expected


Demo Session

50


WiFi Life Cycle Management

Best Practices of Success WiFi Deployment

The WiFi Lifecycle

• Plan – design, capacity planning, inventory, documentation

• Deploy & Validate – Ensure proper installation and

configuration of equipment– Baseline & document for optimal

performance• Troubleshoot – reactive problem

resolution when it breaks

Access Network

Plan

Deploy &

ValidateTrouble-

shoot

Reactive

Proactive(Projects)

Presenter

Presentation Notes

Plan, deploy, validate The primary objective for the IT organization and where they really want to spend their time. This are proactive activities Typical projects are upgrades to the WiFi network, router & switch software or hardware upgrades, or adding additional users to the network during an office build-out. Troubleshoot This is what get’s in the way of the projects The office employees unable to access the network Monday morning or a service outage late Friday afternoon, leading to long hours getting to root cause. Summary Understanding where the customer pain points are in either of those areas is important. It provides you with the business case and the compelling event on why the customer should spend money on our solution.

AirMagnet Mobile• Plan, deploy & validate business critical WiFi networks• AirMagnet Survey PRO/Planner (Design &

Deployment)– Designs and deploys accurate indoor & outdoor Wi-Fi

networks correctly the first time and prevents costly rework– Collects real-world data by performing unique true end-user

experience measurements– Certifies for any design/application requirements using

customer-ready pass/fail assessment reports• AirMagnet Spectrum XT (Interference Troubleshooting)

– Proactively identify and locate ANY radio frequency (RF) interference impacting Wi-Fi network performance.

Access Network

Plan

Deploy &

ValidateTrouble-shoot

AirMagnet Mobile

Presenter

Presentation Notes

AirMagnet mobile offers two products during the project phase for the engineer: AirMagnet Survey PRO/Planner – used during planning, deployment, and validation AirMagnet Spectrum XT – used after deployment has been completed and outside interference need to be identified and remediated. Briefly walk through the bullets

©2015 NETSCOUT ° CONFIDENTIAL & PROPRIETARY

How It’s Used: Planner

• Basic workflow:– Load site details– Define attenuation areas– Define coverage / deployment limitations– Place APs– Verify requirements are met– Document work done

Presenter

Presentation Notes


WiFi Converge Concerns


How It’s Used: Survey

• Basic workflow:– Load map– Determine and configure survey types– Walk site– Verify requirements for deployment are

met– Document work done

Presenter

Presentation Notes

AirMagnet Mobile

• AirMagnet WiFi Analyzer (Troubleshooting)– Real-time independent Wi-Fi network analysis & troubleshooting – Reduces IT costs, simplifies workload and minimizes user complaints

by obtaining instant answers to ANY performance, security & connectivity issues

– Unique active toolset to isolate and troubleshoot Wi-Fi connectivity and wireless network performance issues

Access Network

Plan

Deploy &

ValidateTrouble-

shoot

AirMagnet Mobile

Presenter

Presentation Notes

When problems arise, AirMagnet WiFi Analyzer is used to resolve problems. Briefly walk through the bullets


How It’s Used: Wifi Analyzer

• Basic workflow:– Look for low hanging fruit in AirWISE– Clean up known issues– Use specific screens to analyze more

in-depth issues– Document work done

Presenter

Presentation Notes


How It’s Used: Spectrum XT

• Basic workflow:– Look for identified interferers– Validate that interferers are impacting Wi-

Fi network– Use Find as needed to track down

unexpected devices– Document work done

Presenter

Presentation Notes


Demo Session

83

N E T S C O U T. C O M

THANKYOU

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