Bandwidth Estimation

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In this article

• Overview
• Egress Bandwidth
• Speed Test Bandwidth
• Path Trace

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Overview

The following bandwidth usage guide explains the bandwidth consumption aspects of probing traffic for different probing methods.

Bandwidth usage for probing with path discovery enabled is minimal and unlikely to degrade the network performance of most commercial internet deployments. For example, ICMP probing between an agent and target every 30 seconds consumes only 7.5 MB in monthly egress bandwidth.

Speed test bandwidth usage is significantly greater.

• SEI supports speed testing for 100mbps lines.
• Each speed test bandwidth ranges from 37.5MB for a three-second test to 125MB for a 10-second test.
• Depending on the frequency and duration of speed tests, monthly egress consumption for each agent-to-speed test target ranges from 1.25GB for a three-second test once a day to 90GB for hourly 10-second speed tests.
• In the example below of a single location/circuit with five agents sending ICMP probing ten targets every minute and performing path discovery every hour. The total monthly bandwidth allocation for this deployment is 371.52MB. Running a speed test every six hours from each agent to a single speed test target increases bandwidth utilization by 60GB per month.
• The implication is that speed tests should be used sparingly if bandwidth usage is a concern.

Example bandwidth for an SEI deployment in an Enterprise location:

• 5 agents sharing bandwidth
• 10 targets
• ICMP agent-to-server probing every 60 seconds
• Path discovery every hour
• Speed Test every six hours

Daily Bandwidth Usage By Probing Method

Continous Path Probing
ICMP Packet Size	58 bytes
Probing Interval	60 seconds
Bandwidth Per Day Per Target	84KB
Path Discovery
Packet Width	114 bytes
Hops	20
Attempts	3
Interval	1 hour
Bandwidth Per Day Per Target	164KB
Speed Test 100Mbps
Duration	8 seconds
Test Payload	100MB
Interval	6 hours
Bandwidth Per Day	400MB

Estimated Monthly Bandwidth Consumption

	Agents	Targets	Bandwidth
ICMP agent-to-server probing	5	10	125.28MB
Path Discovery	5	10	246.24MB
Speed Test	5	1	60,000MB
			60.37GB

Bandwidth estimation guide

Use the following bandwidth guidance to understand the general bandwidth requirements of ICMP, UDP, and Speed Test probing.

Bandwidth By Probing Method

Probing Mode	Payload Size (bytes)	Packet size (bytes)
ICMP	16	58 (14byte ethernet header + 20 byte IP Header + 8 byte ICMP Header + 16 byte payload)
UDP	40	82 (14byte ethernet header + 20 byte IP Header + 8 byte UDP Header + 40 byte payload)
HTTP	Variable	Variable
Speed Test	Variable	See Speed Test Bandwidth for sizes of 100Mbs internet speed test configurations

Several factors create variability in the amount of bandwidth an HTTP probing event consumes. These include:

• HTTP Headers: The information in the headers of HTTP responses vary in size
• Connection Setup: Setting up and closing each TCP connection
• Compression: If the server compresses its response, this can change the amount of data sent.
• Network Conditions: Congestion or packet loss on the network can affect how much data is sent and received.

Because of these factors, bandwidth guidance is not provided for HTTP probing.

Egress Bandwidth

Usage per day for different probing intervals

Probing Mode	Interval 60s	Interval 30s	Interval 10s	Interval 5s	Interval 1s	Interval 500ms	Interval 100ms
ICMP	83.52KB	167.04KB	501.12KB	1MB	5.01MB	10.02MB	50.1MB
UDP	118.08KB	236.16KB	708.48KB	1.41MB	7.08MB	14.16MB	70.84MB

Note: (60s interval = 58 * 60 * 24 = 83.52 KB)

Usage per month for different probing intervals

Probing Mode	Interval 60s	Interval 30s	Interval 10s	Interval 5s	Interval 1s	Interval 500ms	Interval 100ms
ICMP	2.5MB	5.01MB	15.03MB	30.06MB	150.3MB	300.6MB	1.5 GB
UDP	3.54MB	7.08MB	21.25MB	42.3MB	212.4MB	424.8MB	2.12 GB

Note: Ingress Bandwidth Usage is similar to egress bandwidth usage for ICMP and UDP

Speed Test Bandwidth

Usage Unidirectional (Download or Upload) - 100MB Internet Speed

Duration	Per Test	Period	Interval 1 Hour	Interval 6 Hours	Interval 12 Hours	Interval 24 Hours
3 sec	37.5MB	Per Day	900MB	150MB	75MB	37.5MB
		Per Month	27GB	4.5GB	2.25GB	1.125GB
8 sec	100GB	Per Day	2.4GB	400MB	200MB	100MB
		Per Month	72GB	12GB	6GB	3GB
10 sec	125GB	Per Day	3GB	500MB	250MB	125MB
		Per Month	90GB	15GB	7.5GB	3.75GB

Path Trace

Linux & MacOS (UDP)

Number of Hops	Per Attempt	Per Test (3 Attempts)	Period	Interval 1 Hour	Interval 6 Hours	Interval 12 Hours	Interval 24 Hours
10	10 * 82 = 0.82KB	2.46KB	Per Day	59.04KB	9.84KB	4.92KB	2.46KB
			Per Month	1.77MB	295 KB	147.6KB	73.8 KB
20	1.64KB	4.92KB	Per Day	118.08KB	19.68KB	9.84KB	4.92KB
			Per Month	3.44MB	590 KB	295 KB	147.6 KB
30	2.46KB	7.38KB	Per Day	177 KB	29.5 KB	14.76 KB	7.38 KB
			Per Month	5.31 MB	885 KB	443 KB	221.4 KB

Windows (ICMP)

Number of Hops	Per Attempt	Per Test (3 Attempts)	Period	Interval 1 Hour	Interval 6 Hours	Interval 12 Hours	Interval 24 Hours
10	10 * 114 = 1.14 KB	3.42KB	Per Day	82.08KB	13.68KB	6.84KB	3.42KB
			Per Month	2.46MB	410 KB	205 KB	103 KB
20	2.28KB	6.84KB	Per Day	164.16KB	27.36KB	13.68KB	6.84KB
			Per Month	4.92MB	821KB	410KB	205KB
30	3.42KB	10.26KB	Per Day	246.e2KB	41.04KB	20.52KB	10.26KB
			Per Month	7.38MB	1.23MB	615.6KB	307.8KB

Note: Packet Length = 114 (14 byte ethernet header + 20 byte IP Header + 8 byte UDP Header + 72 byte payload)