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SoftPhone only on PC connected to Cat 6000?

Unanswered Question
Dec 15th, 2000
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I found this article on CCO which seems to say that a PC running SoftPhone needs to be connected to a Cat 6000 with PFC. If this correct? Can the PC be connected to a 3524, for example, in the closet which in turn is connected to a 6000 with PFC?


Installing SoftPhone

Some enterprises are deploying IP telephony using the Cisco SoftPhone application. In addition, there are many more enterprises that wish to evaluate the viability of using PC-based VoIP applications. Many PC network interface cards (NICs) do not currently set 802.1P CoS bits for Layer 2 classification. Even if the PCs did set Layer 2 frame markings, the vast majority of enterprise administrators would resist "trusting" a user's PC. Because of these factors, Cisco SoftPhone currently classifies voice packets only at the Layer 3 IP header. In fact, all voice bearer packets originating from the Cisco SoftPhone application are marked with an IP Precedence value of 5. Of course, this marking requires a wiring closet Ethernet switch that is Layer 3 enabled, with multiple queues, to correctly queue these voice packets. Currently, this limits Cisco SoftPhone designs to PCs connected to Catalyst 6000 switches with a Policy Feature Card (PFC) installed.

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snoop-09 Sun, 12/17/2000 - 10:54
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You can connect the SoftPhone to anything. All they are saying is that to improve the Quality of Service (QoS), it would be best if only Layer 3 enabled switches were to "route" the voice traffic within the LAN. Layer 2 only switches cannot give a priority to voice traffic, because the only distinguishing factor is the Precedence bit in the IP (layer 3) header.


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