VCON PacketAssistTM Architecture

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VCON PacketAssistTM Architecture
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Common IP Video Deployment Inhibitors

• Bandwidth Management
• Ensure that multimedia traffic does not
  unnecessarily clog the network
• Quality of Service (QoS)
• Ensure users get the best possible audio and
  video quality at a given data rate

PacketAssistTM
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V
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Adaptive Bandwidth Adjustment
Video
Audio

• Automatically adapts to network capacity
  performance
• Adjusts the video data rate dynamically
• Affects both the outbound and inbound data
  streams
• Optimizes conference quality while minimizing
  odds of network saturation

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QoS via Differentiated Services
Router Priority Queues
Inbound Stream
Outbound Stream

• VCON supports both IP Precedence and Diff-Serv
  standards
• Customize personal, group or global priorities
  from MXM console

Best Effort packets (email, internet browsing,
etc)
Prioritized packets (audio, video, etc)
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IP Precedence -vs- DiffServ
IP Precedence
DiffServ
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1
0
DiffServ Code Point

• 0-7 priority assignments
• Different treatment by switches and routers as
  packets flow through the network
• Default precedence values for audio, video and
  RTCP packets can be changed

• Traffic aggregated into Per Hop Behaviors (PHBs)
• Assured Forwarding - high reliability
• Expedite Forwarding - low latency

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QoS Benchmark Test
384K conference with IP Precedence enabled
256K link
384K conference without IP Precedence enabled
Resulting Throughput (bps)

• 97 greater video throughput with IP Precedence
  enabled
• Throughput samples taken each minute - result
  averaged over 20 minutes

Video
Audio
With IP Precedence
Without IP Precedence
Note VCON lab test
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The Multi-Hop Router Effect
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The Multi-Hop Router Effect
VCON PacketAssist corrects for these anomalies
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Overhead Prediction
IP Overhead

• Overhead from IP taken into account during call
  establishment
• As a result, a 384K call should actually consume
  384K of bandwidth on the network
• Especially valuable for network links with fixed
  bandwidth (ie. - CIR frame relay)
• Overhead varies based on the conference data rate

Video
Audio
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Firewall Port Synchronization
Ports configured for H.323 traffic
Full H.323 port range
65535
5000
4800
1024
Firewall

• Firewall is configured so that H.323 traffic can
  only flow over a limited range of ports (ie.
  4800-5000)
• VCON endpoint configured to use this same port
  range
• This feature can also be used for traffic
  filtering and shaping based on specific ports

Configuration performed remotely from the MXM
server
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NAT IP Address Mask
Private (non-routable) IP Address 10.0.0.5
Public (routable) IP Address 192.100.100.155
Header
Payload
NAT

• H.323 control packets usually place the source IP
  address in both the header and the payload
• The NAT changes the header marking when it
  translates the IP address. However, it does not
  change the payload.
• This feature allows the user to manually enter
  their public IP address into the endpoint
  configuration

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Maximum Packet Size Adjustment

• Allows the administrator to change the default
  packet size for H.323 video streams (VCON
  endpoints)
• Useful for mixed voice/video-over-IP deployments
• In some network environments, the large default
  packet size (1500 bytes) for video can choke out
  voice traffic in the routers
• Useful for networks with IP at the edge and ATM
  in the backbone
• Can achieve reduced ATM overhead if the IP packet
  size is aligned with the ATM cell size

Configuration performed remotely from the M XM
server
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QoS - Lip Sync Delay Adjustment
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• User can select the amount of audio latency to
  control lip sync
• Affects the incoming stream from the remote site
• Corrects for poor lip sync in the remote endpoint

Lip Sync Delay
- 1000ms
1000ms
Video
Video
Delay Adjustment
Audio
Audio
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End-to-End IP Video Policy and QoS Architecture
Bandwidth limits Class of service Policy
services Least cost routing
MXM
IP Precedenceor DiffServ
IP Network/Internet
Firewall port synchronization NAT IP address mask
Adaptive B/W adjustment Packet ordering Packet
duplication control Jitter correction Lip sync on
RTP timestamp Lip sync delay adjustment Overhead
prediction Max packet size adjustment
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Asymmetric Network Transmission

• Examples
• xDSL
• Cable Modem
• Satellite
• UnbalancedIP Network

Upstream - 400 kbps
Downstream - 1.5 Mbps

• Automatically adjusts the upstream and downstream
  data rates independently
• Ideal for new last mile network topologies or
  complex IP networks

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Thank You!