Ansi/tia-921-b network Model for Evaluating Multimedia Transmission Performance Over the Internet Protocol

4.4Interfering Stream Files

• 
  IPTV: SD and HD, CBR and VBR
  
• 
  VoIP
  
• 
  FoIP (fax over IP)
  
• 
  Peer-to-peer file transfer
  
• 
  HTTP
  
• 
  OTT TCP video: SD and HD
  

• 
  Flow separation: The captured files are split into upstream (toward the core) and downstream (toward the client endpoint) files for simulation.
  
• 
  Bandwidth analysis: The files are analyzed as to their overall and average bandwidth over finite time periods. As reference files, the microscopic and macroscopic bandwidth characteristics must be understood so that they can be applied reasonably to the various simulation test cases. In particular, the bandwidth characteristics of the files are highly dependent on factors such as the overall bandwidth capabilities and rate limitations of the network path, and the behavior and rate adaptation of higher layer network protocols.
  
• 
  Smoothing: At a microscopic level, bandwidth analysis of some pcap files reveals that there are microbursts. A potential problem with these microbursts is that the instantaneous bandwidth requirement can overwhelm link or memory capacities of the scenario under test. This can be alleviated either through external smoothing of the file or by the rate shaping parameters in the simulation configuration file.
  
• 
  Bandwidth scaling: The standard pcap files are specific captures intended to be representative of network usage. Since they are generic in nature, playback into the simulator is made by bandwidth scaling. This is accomplished by temporal dilation: playback of packets by a constant scale factor, faster or slower, achieves the desired network usage.
  

Figure : Sample Interferer – OTT2 Downstream Flow

4.5Simulation Inputs

Table lists the inputs to the simulation. The core-to-LAN network topology is assumed. One access technology (DSL or GPON) is selected. There are parameters for each network element and for each pcap file used as an interfering traffic stream.
Traffic flows are assigned a priority that is essential in practical access networks to ensure that higher priority traffic from managed services is carried in preference to lower priority traffic. The simulator has 7 priority levels and no per-class bandwidth reservation. The simulation test cases are set as follows:

• 
  1: (highest priority) Managed voice traffic
  
• 
  2: Managed IPTV-type video traffic
  
• 
  3 - 6: Unused
  
• 
  7: (lowest priority) Best effort, OTT video, VoIP/FoIP, peer-to-peer
  

Table : Network Model Simulation Input Parameters

Network Element	Impairment / Interferer	Parameter Range
Core
	Number of Switches	3 to 15
	Total Core Link Delay (ms)	10 to 250
Access (pick one technology)
GPON	Access Rate Down (Mbit/s)	5 to 50
	Access Rate Up (Mbit/s)	2 to 35
	Residual BER	10-12 to 10-9
	Delay (ms)	1
DSL	Access Rate Down (Mbit/s)	3 to 33
	Access Rate Up (Mbit/s)	1 to 3
	Residual BER	10-8 to 10-6
	Delay (ms)	1
	Managed Bandwidth
	IPTV HD Stream 1 - CBR (qty)	0 to 1 (10 core-only)
	Downstream Rate (Mbit/s)	8
	IPTV HD Stream 2 - VBR (qty)	0 to 1 (10 core-only)
	Downstream Rate (Mbit/s)	8
	IPTV SD Stream 1 - CBR (qty)	0 to 1 (10 core-only)
	Downstream Rate (Mbit/s)	2
	IPTV SD Stream 2 - VBR (qty)	0 to 1 (10 core-only)
	Downstream Rate (Mbit/s)	2
	VoIP/Fax (qty)	0 to 1 (10 core-only)
	Rate down/up (Mbit/s)	0.064 / 0.064
	Residual Bandwidth
	Peer-to-peer Rate Down / Up	1.89 / 0.768
	HTTP Rate Down / Up	1.7 / 0.007
	OTT1 Rate Down / Up	7 / 0.128
	OTT2 Rate Down / Up	1 / 0.025
	VoIP/FoIP Rate Down / Up	0.064 / 0.064

Directory: TR-30 -> TR-30.3 -> Public -> 1108%20Arlington
Public -> Document submitted to
TR-30 -> Document submitted to

Download 1.57 Mb.

Share with your friends: