Polycom V2IU 4350 How the ToS Byte Setting Works, Viewing or Changing the ToS Byte Setting

User Manual V2IU 4350 Converged Network Appliance

ToS Byte Setting

Since the Internet itself has no direct knowledge of how to optimize the path for a particular application or user, the IP protocol provides a limited facility for upper layer protocols to convey hints to the Internet Layer about how the trade-offs should be made for the particular packet. This facility is the “Type of Service” or ToS facility.

ToS settings allow the service provider to prioritize time sensitive traffic, such as voice plus video to ensure minimized packet loss and delay through their network. When providing end-to-end QOS, it is important that the voice plus video traffic be placed in the correct queues to deliver a higher QOS than regular traffic. Regular traffic, that is not time sensitive, can be delayed with little or no indication to the user, while the slightest delay in voice plus video can cause auditable differences. The ToS byte setting helps prioritize traffic going to the WAN so a provider can prioritize the traffic correctly in its network.

Although the ToS facility has been a part of the IP specification since the beginning, it has been little used in the past. However, the Internet host specification now mandates that hosts use the ToS facility. Additionally, routing protocols (including OSPF and Integrated IS-IS) have been developed which can compute routes separately for each type of service. These new routing protocols make it practical for routers to consider the requested type of service when making routing decisions.

How the ToS Byte Setting Works

For all RTP traffic (voice and video), the Polycom V2IU 4350 marks the ToS byte in the IP header as “High Priority,” and strips (set to 0) the ToS byte for all other traffic. Unchecking the “Enable ToS Byte Stripping” option means that the ToS byte will not be stripped from non-RTP traffic, but will remain unchanged.

Note: For most situations, you should leave this setting as it is. Only change it if your provider indicates that you should do so.

Viewing or Changing the ToS Byte Setting

To view or change the ToS byte setting, use the following steps:

1.Using the configuration graphical user interface, from the Configuration Menu on the left-hand side, click Traffic Shaper.

2.Scroll down the area of the screen shown below.

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