![]() ![]() Problem: Not all Live Communications Server functionality works through ISA Server 2004.Ĭommunication between two clients on the same side of the ISA Server computer should work in a simple internal network configuration. Live Communications Server Has Limited Functionality through ISA Server Relevant part of the article quoted below Live Communications Server used SIP and it became a problem. Troubleshooting Unsupported Configurations The article was for ISA2004 but it continued to be a problem all the way to TMG2010. SIP being the example here, but was true for any complex protocol that carries connection information inside the payload where the NAT process is left "unaware" of it and hence cannot manage the connection properly. This is a link to the material using ISA Server as an example to show the issue with complex protocols. People from the product team back then even admit to that to us (the MVPs), but never changed the documentation or the wording in the GUI. Even MS does in the ISA/TMG product when they refer to Application Layer Filters which are actually Application Layer "proxys". This will ensure that traffic will be forwarded within the internal network with the correct priorities assigned to it.I am saying that Watchguard does that in how they use terminology in their documentation. That traffic must therefore be re-marked immediately by the enterprise network border device. Inbound direction: Internet traffic may arrive at an enterprise site incorrectly marked.Outbound direction: Traffic often arrives at the unified communication services cloud with improper marking.Such re-marking has the following implications: Internet service providers - Internet Service Providers frequently re-mark DSCP priority values to different (lower) values.Mobile applications mark traffic with a DSCP value according to Table 4.1.1.Media servers - Cloud media servers mark UDP media traffic as DSCP 46 (voice) or DSCP 34 (video).▪ Configure the first Layer-3 device away from the soft endpoint to re-mark traffic appropriately.▪ Configure an operating system policy (group policy) to override this behavior.To prevent packet reset, you have two options: However, the operating system may reset the packets to a DSCP value of 0. Soft endpoints (softphones, video client, MVP, and Google Chrome clients) mark UDP media packets according to the proper priority marking.This configuration lets routers in an enterprise network prioritize VoIP media traffic over Best Effort data traffic. Deskphones use IP Differentiated Services Code Point 46 (Expedited Forwarding, or EF) marking for UDP media (RTP) packets.Depending on the quality of the satellite connection, such delays may cause excessive jitter and packet loss. Satellite connections can introduce delays greater than 150 ms in each direction.This capability may cause intermittent signaling and media traffic issues. ![]() The Green Ethernet setting saves energy by automatically setting switch ports to low-power mode after a period of inactivity.Use of Auto-QoS may cause voice-quality issues (e.g., distortion or incorrect volume levels) with older Poly speakerphones and older deskphones.Signaling and media for a single session must originate from the same IP address. Packet-by-packet load balancing across multiple internet connections is not supported.Port filtering, such as UDP flood protection, may limit bandwidth, which can cause intermittent voice-quality issues during simultaneous calls.Web proxies do not typically support QoS, so any VoIP or video traffic that passes through these proxies may suffer excessive latency and jitter.WAN accelerators use header compression to reduce bandwidth consumption, which can cause increased jitter in VoIP traffic.IDS/IPS functions may limit packet streams to a specific bandwidth, causing intermittent audio problems when the number of calls exceeds a certain limit.You must disable SIP inspection, which may cause intermittent call-control or media-transport problems.Enabling SIP ALG may cause signaling issues that can result in nonfunctional or partially functional call features, and/or one-way audio or lack of audio.(The effect will likely be minimal if you use advanced networking devices.). If you use SMB or SoHo devices, this configuration could result in substantial problems. For some of the functionalities listed in the Application row of Table 2.1, packet content may traverse a separate processing engine, resulting in signaling and/or media traffic impairments. ![]()
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