Real-World Signaling & Traffic Impairments Simulation over IP Networks
(Delay, errors, loss, retransmissions, reorder, duplicate,…)
10th, Dec 2017
Welcome to another December 2017 issue of GL’s Newsletter. In this edition we discuss on Real-World Signaling & Traffic Impairments Simulation over IP Networks such as delay, jitter, errors, loss of packets, retransmissions, reorder, duplication, and combinations thereof. As depicted below, the traffic affected may be real or simulated, different mixes of voice, video, and data, and variable in speed.
Overview
Test tools that allow operators and service providers to generate real-world IP impairments are extremely useful to evaluate performance of networks. A few of the desired features in such test tools include, the ability to use test tools either in the lab environment or on live networks, capacity to control the test sequences and monitor results remotely, test automation, capability to change test parameters dynamically, and higher accuracy.
Packet loss can include a straight-forward % of packets to be lost to simulate burst models where for an error event a certain number of packets will be disrupted. Latency or packet delay, and jitter, the variance in inter-packet delay, out-of-order packets, duplicate packets, and network congestion are other types of packet impairments expected to be seen.
Some of GL impairment generator tools that meet above requirements and help in study of network behavior over IP are discussed briefly in this newsletter.
- Hardware Based Impairment Generation Tools - offers accuracy, higher bandwidth and variety of ways to corrupt outgoing packets
- IPNetSim™- Multi-Stream WAN Link Simulators available in 1 Gbps, 10 Gbps versions
- IPLinkSim™- Single Stream WAN Link Simulators available in 1 Gbps, 10 Gbps versions
- Other Traffic Generation Tools - offers applications to generate and/or replay traffic to simulate real-world conditions
- PacketExpert™- Multi-Functional Ethernet test tool available in 1 Gbps, 10 Gbps versions
- MAPS™ RTP HD (UMTS IuCS, GSM A/Abis, SIP, BICC, MGCP, MEGACO,…) - High-volume Signaling and RTP Traffic Generator available in 4 Gbps or 10 Gbps versions
- MAPS™ PacketLoad (LTE S1/eGTP, GnGp, UMTS IuPS/IuH/GnGp) - - High-volume Signaling and Mobile GTP Traffic Generator available in 4 Gbps or 40 Gbps versions
Hardware Based Impairment Generation Tools
A detailed comparison of WAN Link Simulators given below, provides you with all features that help to simulate impairments -
| Features | IPLinkSim™ | IPNetSim™ |
|---|---|---|
Packet Delay, |
Constant, or Distributed (Uniform /Random Exponential) Max Delay - |
Constant, or Distributed (Uniform /Random Exponential) Max Delay - |
Packet Errors |
Single, Periodic, FCS Errors - |
Single, Periodic, FCS Errors - No |
Packet Loss |
Single / Burst Drop, Periodic/Random Drop, Manual Drop |
Single / Burst Drop, Periodic/Random Drop, Manual Drop |
Packet Reorder |
0.01% - 100% |
0 - 100% |
Packet Duplication |
0.01% - 100%, Periodic, or Random |
0 - 100% Periodic, or Random |
Bandwidth Throttle |
Yes (1 - 100%) |
Yes (1 - 100%) |
Congestion |
Yes with Background Traffic |
No |
Hardware Filters |
No |
Yes |
Bandwidth Capacity |
1 Bi-directional Link 2x 1Gbps ports (Single stream) 2x 10 Gbps ports (Single stream) |
1 Bi-directional Link 2x 1 Gbps ports (16 Multi-streams per bi-directional link) 2x 10 Gbps ports (4 Multi-streams per bi-directional link) |
Interfaces |
Electrical and Optical |
Electrical and Optical |
Accuracy |
1.4 Million frames/s |
1.4 Million frames/s Up to 120 bytes wide stream definitions covering entire packet header from MAC to UDP and also Payload |
Availability |
Available on Windows® CLI and C/C# APIs Supported for Remote Access and Automation Management Port - Yes |
Available on Windows® CLI and C/C# APIs Supported for Remote Access and Automation Management Port - Yes |
Operational Mode |
Bridge |
Bridge |
Reporting |
Yes - Live throughput graph view, Tx and Rx Frames, Dropped Packets (due to Bandwidth Control), No. of Packets with Errors, Dropped Packets (due to Packet Loss), Duplicated Packets, Reordered Packets, and average throughput, for varying durations. |
Yes - Live throughput graph view, Tx and Rx Frames, Dropped Packets (due to Bandwidth Control), No. of Packets with Errors, Dropped Packets (due to Packet Loss), Duplicated Packets, Reordered Packets, and average throughput, for varying durations. |
Other Traffic Simulation Tools
PacketExpert™ 1G and PacketExpert™ 10G are general all-purpose Ethernet test tools that can generate and analyze the incoming Ethernet traffic. These are available as either portable or as rackmount network appliances. The Multi-stream Traffic Generator and Analyzer application within PacketExpert™ is capable of generating multi-stream Ethernet traffic of varying packet length and also analyze the loopback traffic. The Record and Playback within PacketExpert™ is a wirespeed traffic generator and capture application that gives the user flexibility in recreating any kind of live network conditions - i.e., traffic captured on a live network (using either PacketScan™ or Wireshark®) can be easily recreated in the lab. The Record-only application captures packet and timestamped at the hardware level, thereby achieving nanosecond timestamp precision.
MAPS™ RTP HD and MAPS™ PacketLoad can emulate any or all of nodes in a network infrastructure to create an end-to-end call scenario from the user initiating a voice call or internet connection to the data server, responding to that request and all other necessary exchanges in between. These are available as special purpose rackmount network appliances with high-density NICs capable of high call intensity (20k+ calls/sec) and high volume of sustained calls (tens of thousands of simultaneous calls/platform).
With PCAP Replay option, any combination of traffic type is possible to create. You may pre-capture actual traffic to file (PCAP) and replay in lab environment to quickly pin-point issues using external protocol analysis tools such as PacketScan™ HD.
A few features of these network appliances that help in generating/reproducing network traffic and study network behaviour are briefly listed in the table below -
|
PacketExpert™ 10G |
MAPS™ RTP HD |
MAPS™ PacketLoad |
Packet Capture |
Yes - Supports PCAP, PCAPNG, HDL, DAT file formats |
No |
Yes - Supports PCAP file formats |
Packet Replay |
Yes - Supports PCAP, PCAPNG, HDL, DAT file Formats |
No |
Yes - Supports 100 Concurrent PCAP Files, and pre-canned HTTP file playback (*.txt). |
Packet Generation |
Yes - through |
Yes at wire speed |
Yes at wire speed |
Hardware Filters |
Yes |
No |
No |
Bandwidth Capacity |
1 Gbps to 10 Gbps 2x 1 Gbps ports |
4 Gbps and 20 Gbps 20K+ User Simulation 4 Gbps 20 Gbps |
4 Gbps and 40 Gbps 100k+ User Simulation 4 Gbps 40 Gbps |
Interfaces |
Electrical and Optical |
Electrical and Optical |
Electrical and Optical |
Availability |
Available on Windows® CLI and C/C# APIs Supported for Remote Access and Automation |
Available on Windows® CLI and C/C# APIs Supported for Remote Access and Automation |
Available on Windows® CLI Supported for Remote Access and Automation |
Reporting |
Live throughput graph view, |
Detail Packet Tx/Rx Statistics, RTP MOS quality scores; Uses-off-the-shelf tool for detail RTP statistics and voice quality analysis - PacketScan™ HD |
Total packets transmitted and received, Latency, Delay, Bandwidth, No of TCP connection created, Successful connection, Packet loss, etc |
In addition to the above hardware-based test tools, GL offers below software-only test tools that offer cost-effective solution to perform detail functionality testing.
- MAPS™ IP Test Tools (LTE, IMS, DIAMETER, UMTS, GSM, GPRS, BICC, MAP, SIP, MGCP, MEGACO,…) - These tools are multi-protocol and multi-interface tester that perform complete end-to-end simulation of signaling and traffic between any two points in the network infrastructure. For more specific and detailed testing, MAPS™ applications run script based call setup and tear down using different protocols. As part of this implementation, MAPS™ simulator can select specific messages in the protocol and use logical operators to insert data into or corrupt fields in the messages starting at the signaling link level. MAPS™ supports low level impairment capability by manipulating forward and backward call messages (on a per call basis) just before sending over transport.
Logical operators can be used to apply a specific impairment to a specific message over the system and impairments can also be set on the RTP path. This requires the user to know where in the frame of a particular message to insert the impairment or to corrupt.
- PacketCheck™ - A software based Ethernet tester with BERT and Throughput testing abilities. It is very easy to use as a general-purpose network performance analysis tool for 10Mbps, 100Mbps and 1Gbps LANs and WANs. The application generates multi stream Ethernet/IP/UDP traffic with on-demand bandwidth (up to 800 Mbps) and measures end to end performance such as Bit Error Rate, Total Packets, Packet loss, Out of Sequence Packets, and Erred Packets. Additional features include transmission of pre-recorded file traffic, GTP traffic simulation, impairment generation, Bursty and Fixed IFG (Inter Frame Gap) traffic generation mode, and Delay measurements, with provision to generate PRBS patterns or user-defined test patterns.
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